Every week, we post ScienceShots, short news items where the picture is often as stunning as the story itself. Below is a collection of all of the “Shot” images we’ve run this year. Click the image for a larger version and to read the story behind the art. See also our Top 10 ScienceNOWs of 2011.
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Solar Wind Stifles Mercury's Magnetic Field
Ever since NASA's Mariner 10 spacecraft zipped past Mercury in 1974, scientists have wondered why the planet's magnetic field is so much wimpier than
expected. Now, a new study led by researchers at Braunschweig University of Technology in Germany suggests that the solar wind—the incessant flow of
charged particles boiling off the sun's surface—suppresses the field generated by the flow of molten iron in the planet's outer core. On the sunward
side of Mercury, the magnetopause—the protective shield created by the planet's magnetic field—sits just 1200 kilometers above the planet's
surface. That's so close, the team's computer models indicate, that magnetic fields created by particles flowing along the magnetopause reach deep into
Mercury itself, counteracting the internally-generated field. Without the external fields generated by the solar wind,
Mercury's magnetic field might be about 30 times stronger than it actually is, the researchers report today in Science. NASA's MESSENGER probe (artist's concept above) has been orbiting Mercury since mid-March and will
provide unprecedented measurements of the strength and direction of the planet's magnetic field, revealing more about how such fields are generated in
the first place.
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Performing Surgery on Your Christmas Turkey
If you're having turkey for Christmas dinner, be sure to invite a veterinarian. A group of European vets has figured out the best way to sew up a
deboned bird. After taking the major bones out of a handful of turkeys and filling them with stuffing, the group tried out four different stitch
patterns—arrangements that they use professionally to fix a horse's intestines or sew up a cat after surgery. A fifth turkey got skin staples
(shown). The turkey sewed with the simple stitch, akin to that a home cook might try (poking the needle into the skin on one side, then up through the
other side) had the most torn skin before cooking. The other three stitch patterns still looked decent after cooking, but when the sutures were
removed, a lot of skin and meat came with them. The best-looking turkey, it turned out, was the one that had been stapled. "You will finally be able to
impress family and friends with your surgical skills at a Christmas or Thanksgiving dinner," the authors conclude in a paper published online today in Veterinary Record. Although they also warn that, while absorbable sutures will be digested if you accidentally leave one behind, a forgotten
skin staple could cause problems for your guests' teeth or innards.
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Giant Dino Lived in Antarctica
Before penguins ruled Antarctica, dinosaurs roamed across what was then a forested continent, migrating over from Australia and other land masses that
were connected to it at the time. Several Antarctic dinosaurs have already been found, including an armored ankylosaur and a handful of birdlike
dinosaurs. But researchers working on James Ross Island off the Antarctic Peninsula have now reported the discovery of what may be the biggest dino yet: a fossil (inset) from the tailbone of a sauropod, a giant, four-legged dinosaur with a long neck and
tail. As they write in Naturwissenschaften this week, the researchers believe this plant-eating beast lived during the Cretaceous period, which
lasted until about 65 million years ago. The team can't identify which of the 150 sauropod species the dinosaur belonged to, but it hopes to find some
of his friends still buried in the frozen wasteland.
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Future of Frankincense Not So Sweet
The mythical gifts of the Magi—gold, frankincense, and myrrh—represented the rarest and most precious tributes one could give a king.
Unfortunately, frankincense, a sweet-scented resin from the desert tree Boswellia, has become even rarer and will continue to do so, researchers
report today in the Journal of Applied Ecology. Boswellia trees have had trouble reproducing in recent years, and ecologists believed
that they were weakened when traders tapped them for resin. Working in Ethiopia over a period of 2 years, the researchers monitored 12 copses of B. papyrifera: six that had been tapped and six that had not. They found that the tapped trees were able to reproduce as well as the
untapped, ruling out human interference as the major killer. Instead, the biggest threats seemed to be grazing livestock, fires, and the longhorn
beetle, which burrows into trees' bark, kills them, and leaves them as ready fuel for forest fires. If these problems aren't remedied soon, the team's
models suggest that frankincense production could drop by 50% in the next 15 years: a tough blow to the economies of Ethiopia and Eritrea who
export it.
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Probing a Black Hole
How do you probe a supermassive black hole? Take a look at the pulsars that orbit it. These rapidly spinning neutron stars flash regular radio pulses,
and in an upcoming issue of The Astrophysical Journal astronomers say that the timing of such pulses could provide a new understanding of the 4 million solar mass black hole at the center of the Milky Way.
Scientists
have speculated that physics as we know it could break down in the presence of
such a strong gravitational force. If
that's the case, any flashes from nearby pulsars would appear to speed up or slow down when viewed from Earth, with their clocklike arrival times
running early or late and likely dependent on where their orbits were in relation to the black hole. In the process, the astronomers also hope to
determine Sagittarius A*'s spin rate and true mass down to an accuracy of about 1 part in a million. First, though, they have to find pulsars close
enough to this gravitational monstrosity to be useful. And that's not expected to happen until the Square Kilometer Array comes online early next
decade.
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A Bar at the Center of the Milky Way
Believe it or not, there's a bar in space. But you wouldn't want to order drinks there. New observations led by astronomers at the Cerro Tololo
Inter-American Observatory in northern Chile confirm that about 10,000 red giant stars—which are much older and brighter than our sun—orbit the
center of the Milky Way, creating what looks like a large cylindrical bar (artist's impression,
shown). Other stars in that region of space presumably orbit the galactic center in a similar fashion. The research also suggests that the axis of the
bar is pointed almost directly at our solar system, with our sun (which sits in a spiral arm of the Milky Way between one-half and two-thirds of the
distance from the galaxy's center toward its edge) lying about 20° off the bar's axis. Perhaps the results will inspire a new drink: The Red Giant.
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A Shirt That Cleans Itself
Tired of washing your clothes? In the future, the chore might be as easy as hanging them in the sun, according to researchers who have developed a type
of self-cleaning cotton. The idea is not totally new: Coatings such as titanium dioxide have long been known to have self-cleaning properties. When
light strikes, the compound emits oppositely charged particles known as electron-hole pairs, which encourage so-called oxidation reactions, breaking
down organic material such as dirt. But the light has to be ultraviolet, which makes up only a small percentage of sunlight and which, therefore, makes
this process inefficient for everyday use. Now, however, the researchers have tried coating cotton with nitrogen-doped titanium-dioxide (N-TiO2) and an extra layer of silver-iodide (AgI). In visible light, the N-TiO2 and AgI seem to work together, forcing any generated
electrons and holes to separate so that they stand less chance of recombining—ultimately making them more efficient at oxidation. In their report,
due to be published later this month in Applied Materials & Interfaces, the researchers describe how
a piece of treated cotton stained with orange dye self-cleaned when exposed to a 1000 Watt lamp for 2 hours. But what if you do actually want to wash this special cotton? It's OK: the self-cleaning coating stays put.
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Celestial Snow Angel
Just in time for the holidays, the folks at the Space Telescope Science Institute in Baltimore, Maryland, give us a glimpse of a heavenly angel—not
literally one of the seraphim, of course, but an astronomical delight nonetheless. The two-lobed star-forming region, dubbed Sharpless 2-106, is
located in an isolated part of our Milky Way galaxy nearly 2000 light-years from Earth. The bluish "wings" are lobes of super-hot gas illuminated by a
monster star—dozens of times the mass of our sun—forming in the center of the still-expanding nebula. A dark ring of dust and gas circling the star
(dark bands, center), material that may one day coalesce into a planetary system, acts like a belt, cinching the nebula into an hourglass shape.
Observations of the nebula at purely infrared wavelengths reveal more than 600 brown dwarfs, so-called "failed stars" that each gives off more heat
than it receives but lacks enough mass to ignite and produce nuclear fusion on its own.
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Ant 'Gas Gun' Paralyzes Prey
Some ants don't fight fair. Scientists have discovered that a common African ant deploys a powerful venom to kill termites—at long range. At the
edge of forests in Cameroon, researchers saw gangs of up to 15 ants (Crematogaster striatula) waft a venomous vapor from their stingers at a
termite. The ants then watched from a safe distance as the much-larger victim became paralyzed, died, and later dragged back to their nest (seen in
picture), the researchers report today in PLoS ONE. The remote-action poison allows the ants to kill prey without exposing themselves to harm. Even the threat of the poison seemed to scare off enemies, including other species of ants, which abandoned drops of honey when confronted with a
loaded C. striatula stinger. The researchers hope that once the paralyzing molecule is identified, their discovery will lead to new insecticides
effective against pests that shrug off older products.
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Hairy Men Make Good Bedbug Catchers
When it creeps into your bed at night and crawls across your skin, the bedbug (inset) has to navigate a forest of body
hair before plunging its proboscis into your flesh for a meal. One wrong step, and it could get smushed. Tickled by the question of how people detect
such microscopic pests, researchers recruited 19 volunteers with various amounts of body hair and shaved one of each of their arms. They then asked the
subjects to look away while they dropped bedbugs onto their arms. The volunteers hit a button as soon as they felt something crawling on them.
Participants, especially men, with more hair follicles per square inch and whose body hairs were longer, tended to be
several seconds quicker than less hirsute individuals to notice the bugs on their unshaven arms, the researchers report online today in Biology Letters. And everyone took a long time to notice the bedbugs on the shaved arm. That might
explain why humans still have hair on their bodies, the researchers conclude, since we no longer need it for keeping warm.
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Light Me Up, Buttercup
Not sure you like butter? The buttercup knows, casting a yellow spot on the chin of all butter-lovers, or so says childhood lore. Now researchers have
illuminated the flower's ability to ferret out butter fans. Armed with microscopes and a spectrometer, which analyzes the wavelengths of reflected
light, the team found that the petals of the buttercup (Ranunculus repens) have a transparent outer coating that reflects light, enhancing the
blossom's shine. Beneath that coating, a layer of yellow pigment rests on a layer of air. Light passes through the pigment, bounces off the air and
zips back through the pigment before reaching a viewer's eye, according to a study published online today in The Journal of the Royal Society Interface.
The light's double passage through the pigment creates an intense yellow. The buttercup is so glossy that if held at the right angle, it reflects sunlight onto human skin, like a mirror. Thanks to its pigment, the flower
reflects yellow light—even onto the chins of butter-haters.
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Don't Worry, Little Planet
How often do stars eat their young? Almost never, according to a paper submitted to The Astrophysical Journal. While planets typically
migrate inward due to the torque (or gravitational push) of the pancake-like proto-planetary disks of dust and gas in which they form (seen in this
picture), what hasn't been clear until now is what causes them to stop. In the new study, researchers ran computer simulations on 126 confirmed
extrasolar planets detected by ground observatories and 649 candidate extrasolar planets detected by NASA's Kepler spacecraft. Their results indicate that planetary migration is actually stopped by a gap that is created by the star's accretion of material from
the disk. There, the disk's torque driving the planet's inward migration disappears and the planet stabilizes in roughly a 4-day orbit (about 10 times
the radius of a solar-type star). Based on their findings, the scientists conclude that cannibalized planets are extremely rare.
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Standing Tall to Beat the Heat?
Stand upright, cool off. That's long been touted as one of the benefits of our ancestors becoming bipedal in a hot and sunny world. But now researchers
have poured cold water on the idea. A team examined how our ancient relatives, who were most likely covered with a thick pelt of hair, would fare while
walking briskly in a sizzling place like the African savanna. The body dimensions used in the model—30 kg for females, 55 kg for males—were based
on a group of early human ancestors, or hominins, such as Australopithicus afarensis, the species that includes the famous Ethiopian fossil "Lucy." The models showed that
a 30-minute trek put hairy hominins at risk of heat stroke whether they were four-legged or erect
, according paper published online today in the Proceedings of the National Academy of Sciences. Earlier models supporting the connection
between bipedalism and heat loss examined ancient humans standing still in the sun, which the new paper's authors argue is less realistic.
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*This item has been corrected. Lucy was found in Ethiopia, not Kenya.
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'Burgeroids' Cause Double Rainbows
Red and yellow and pink and green—for scientists, a rainbow isn't much of a mystery. Sunlight bounces off raindrops, splitting into its constituent
colors and heading backwards at a precise angle, which makes a rainbow appear as a semicircle wherever you stand. But what about two rainbows at once?
Now, researchers performing computer simulations think they have an explanation for this odd phenomenon. The key are what the researchers call
burgeroids—big raindrops that have been flattened by the buffeting of air. The simulations (pictured) showed that
this irregular shape causes the light to bounce off the raindrops at two different angles, producing a colorful, double rainbow in the sky. The researchers hope that their study, which is due to be published later this month in ACM Transactions on Graphics, could make computer graphics more lifelike for use in animated movies and computer games.
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Grand Canyon Too Crowded in Spring? Blame Climate Change
Climate change has already altered the timing of plants blooming, insects hatching, and birds migrating and breeding. Now, researchers have found that it may be altering human vacation plans as well. A team analyzed attendance data at U.S. national parks from 1979 through 2008. Of the 27 national parks that had seasonal variations in attendance, at least 100,000 visitors in 1979, and for which long-term attendance data were available, nine parks showed increases in average temperatures in spring, according to weather data collected there or nearby. And at seven of those nine parks, peak attendance moved forward an average of 4 days over the 30-year period, the researchers report in an upcoming issue of International Journal of Biometeorology. At Grand Canyon National Park (shown), for example, peak attendance shifted from 4 July in 1979 to 24 June in 2008. At the 18 parks analyzed that didn't experience climate change, only three showed shifts in peak attendance. The researchers blame climate change for the shifts: A warmer and longer spring allows tourists to visit parks earlier, which nudges peak attendance earlier in the year, they contend. Other major factors likely to influence park visitations—including population growth, economic trends, and travel costs—would tend to affect the total number of park visits but not their timing within the year, the researchers say.
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Sniffing Out the One in a Quadrillion
Detecting tiny amounts of gases might seem dull, but when it comes to spotting traces of toxic substances that are intended for chemical attacks, it can make the difference between life and death. Now, scientists have improved the sensitivity of gas detection almost 1000 times over, paving the way for more-rigorous security operations and even a novel way of performing carbon dating. The method requires a gas mixture—perhaps sampled from a suspect area—to be injected via a tube into a cavity with parallel mirrors on each side. When laser light is shone into the gas mixture, it bounces back and forth between the mirrors so many times that it clocks up about 10 kilometers. Over this distance some of the light is absorbed, and the wavelength at which it is absorbed reveals what types of molecules are present. Tested on a carbon dioxide mixture, the method detected a minuscule component—just 43 parts in every quadrillion—that contained radioactive carbon atoms rather than normal carbon atoms, the team will report later this month in Physical Review Letters. Aside from more sensitive detection of chemical-warfare agents, the technique offers a cheaper and simpler way to age artifacts via carbon dating, which usually requires huge particle accelerators to extract radiocarbon atoms from a sample.
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Measles Transmission—As Seen From Space
Light punctuates the darkness in this satellite image of Niger and northern Nigeria. In a new paper in Science, scientists show that such pictures can help them explain and predict outbreaks of measles in the area. Researchers suspected that the seasonal surges in measles—a major childhood killer—were caused by people moving into Niger's cities at the start of the dry season, but they didn't have an easy way to quantify those movements. Researchers at Princeton University and Pennsylvania State University, State College, wondered whether they could use changes in nighttime light, both from electrical lights and fires, as a proxy for population density. It was an "off-the-wall idea," says Matthew Ferrari, one of the scientists, but it worked. In the paper, the team shows that upswings in brightness correlate well with measles outbreaks. Nighttime shots could find much wider use as an indicator of population density, the researchers say, for instance, in studies of economic development or during refugee crises.
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Polar Bear Cannibalism on the Sea Ice
On 24 August 2008, a photographer observed a polar bear guarding its kill out on the sea ice in Svalbard, Norway. Not an unusual event—except that the prey it held in its mouth was another polar bear, a 2- to 3-year-old juvenile. Even that was not unheard of: Inuit hunters in Greenland and Canada have long known that polar bears—usually adult males—might kill younger polar bears for food. But such events have only been reported on land, not on sea ice, and no one had photographed it before. Since then, says the photographer, Jenny Ross, there have been two other documented sightings of adult male polar bears on sea ice feeding on their younger bear kills, one in September 2009 and one in July 2010. Given the dwindling sea ice and the scarcity of seals nearby at that time of year, young polar bears may simply be the most available prey, Ross and Arctic biologist Ian Stirling of Environment Canada in Edmonton note in the December issue of Arctic. But, they add, it might also be a sign of things to come: A warming climate and less and less sea ice will send seals northward even earlier in the summer, and the frequency of intraspecies predation could increase.
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The Brain of a Cabbie
London taxi drivers aren't like the rest of us. Researchers have known for more than a decade that these elite cabbies—who train for years to master "the Knowledge," a mental map of 25,000 streets—have a larger than average rear hippocampus, a brain region linked to learning and navigation. What scientists didn't know was whether the drivers grew bigger hippocampi as they trained or whether they had big ones (and thus an innate navigation advantage) to begin with. So a team followed three groups—trainees who successfully acquired the Knowledge and became cabbies, trainees who failed to qualify, and a control group of non-taxi drivers—over 4 years, testing them and scanning their brains before, during, and after training. They found that the brains of qualifying trainees were no different from those of nonqualifying trainees or non-taxi drivers before beginning training. But as the cabbies learned the Knowledge, their hippocampi grew (see the progression from left to right), literally changing their minds, the researchers report online today in Current Biology. The hippocampi of unsuccessful trainees stayed the same throughout, which could suggest that successful cabbies really do have an innate advantage—their brains are more malleable than others'.
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Lessons from the Mississippi Floods
SAN FRANCISCO, CALIFORNIA—The April and May 2011 floods along the Mississippi River were among the most damaging of the last century. But scientists hoped for a silver lining:
evidence that floodwaters would inject a much-needed supply of sediments into to the region's rapidly eroding wetlands. Research presented here
yesterday at the American Geophysical Union's fall meeting here, however, suggests mixed results from this "natural experiment."
On the downside, satellite analyses, boat surveys, and sediment sampling revealed that the Mississippi River injected its sediment directly into the
Gulf of Mexico, bypassing the wetlands. However, a plume of floodwaters diverted through the shallower, slower Atchafalaya Basin, a wetland connected
to the Mississippi through the Morganza Spillway, distributed its sediments more widely among the coastal marshes. Although that's cause for hope, the
mixed results suggest managers wishing to rebuild the wetlands by diverting the river's flow will need to think carefully about where to divert the
waters.
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Hide and Seek in the Cambrian
About 515 million years ago the Cambrian seas were home to the weirdly wonderful predator Anomalocaris. The creature, seen in this artist's
impression, was a distant cousin of arthropods, with eyes on stalks and a circular mouth containing interlocking plates that might be best described as
a camera shutter of doom. These features have led paleontologists to think that Anomalocaris was a formidable predator of creatures like worms
and trilobites, but, until now, exactly how this animal saw its prey has been a mystery. In a new study, published online today in Nature,
paleontologists report that they have found a unique specimen of Anomalocaris with exceptionally-preserved fossil impressions of the animals'
eyes.
The creature apparently had at least 16,000 hexagon-shaped lenses in each eye that would have given it hi-res vision similar to the visual abilities of living dragonflies. The fact that Anomalocaris had such keen eyesight
may have been part of an early evolutionary arms race, the authors suggest. As predators evolved better vision, their prey must have developed better
armor or other defenses. Hide and seek with Anomalocaris was certainly a dangerous game.
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Frog Songs Advertise Real Estate
Singing in the shower isn't a turn on—unless you're a frog. Male Emei music frogs (Babina daunchina) advertise their home-making skills by serenading females from inside their muddy burrows, researchers
report online today in Biology Letters. These small Chinese natives, which attract females by belting out quick chirps, dig deep caverns near
ponds for shelter and raising tadpoles. Males sing both inside and outside of their soggy abodes, but the tunes
aren't created equal. (Listen to examples of each below.)When males belt out solos from safe inside their burrows, their calls tend to be deeper and longer, giving females a good sense
of how deep the holes are and how wide their entrances may be. And the females seem to prefer studs that can keep house. The team played back recorded
calls to would-be mates and found that about 70% of females hopped toward songs taken from inside a burrow rather than out.
Frog Songs
Listen to Emei music frogs try to court females.
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A Sense for Supper
Scientists have long thought that many of the tiny marine crustaceans called copepods find their supper by colliding with it. Now new research shows
the truth is less painful. Scientists unleashed Metridia longa, a copepod of the northern seas, into tanks of algae and found that an algal cell
didn't have to bump into a copepod to be detected. Instead,
algae that merely floated close to a copepod's antennae set off an "attack response," in which the copepod creates suction to draw in its prey, the team reports online today in Biology Letters. Researchers think the crustacean is
responding to either chemical signals or the touch of an algal cell on its antennae. Either way, this detection method, which has never been described
before, could help explain how copepods survive in the ocean, where food is so scarce that it's inefficient to rely for meals on things that go bump in
the night.
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Insect Invader Rubs Shoulders With Ants
Talk about being embedded in enemy territory. A newly described species of silverfish (Malayatelura ponerophila)—a 6-millimeter-long
golden-brown insect with spikes on its tail—spends its entire life among a colony of army ants (Leptogenys distinguenda). So how does it
avoid be spotted? By rubbing against baby ants to pick up their scent, researchers
report online this month in BMC Ecology. The ants rely mostly on chemical cues to identify their nest mates, and as long as the odor doesn't
fade away, the silverfish gets free food and shelter. The silverfish can't get too lazy, however. If it doesn't continually replenish the scent, the
ants grow wise and attack their uninvited guest.
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Do Presidents Age Faster Than the Rest of Us?
Three years into his presidency, Barack Obama has far more wrinkles and grayer hair than when he was a senator from Illinois. And Bill Clinton left the
White House looking more than 8 years older. It seems like presidents age faster than people with normal jobs—one physician has suggested that they age twice as fast. But a new study, published today in the Journal of the American Medical Association, finds that it's not all bad for American leaders. By comparing presidents to other men of their
eras, researchers discovered that commanders in chief die at about the same age as their peers. They certainly don't
age at double the speed. Many live longer, probably because most have been wealthy, college-educated, and able to get good medical care. So why does
being in office wrinkle presidents? Probably, the researchers say, because they're just getting older like the rest of us.
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Insomnia Linked to Punctuality
Insomniacs have one thing going for them: They're punctual. New research finds that
people who snooze for the shortest, most fitful intervals arrive more promptly for appointments than sounder sleepers. In the study, reported in a forthcoming issue of the Journal of Sleep Research, scientists scheduled volunteers for overnight observation at a
sleep clinic, noting the time they arrived for their appointments and swiped their insurance cards. Those who showed up earliest also slept the worst. Previous
studies have linked insomnia to perfectionism, and because excessive punctuality is a form of perfectionism, the new work supports that link. Whether
it's perfectionist traits that cause insomnia—or vice versa—warrants further study, however. The researchers next plan to explore whether
psychotherapy aimed at reducing obsessive behavior may help curb insomnia—though patients may start coming late to their appointments.
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Human Hearts Beat Together
It's not always easy to follow your heart. But for human babies and their mothers, following each other's hearts may be as simple as sharing a
smile. A new study shows that 3-month-old infants and their mothers can synchronize their heartbeats to mere milliseconds. Researchers sat 40
pairs of mothers and infants face-to-face, equipped with sticky skin electrodes on either side of their hearts. Beat for beat, mother-and-child hearts
thumped together almost instantly as they shared loving looks or contented coos. This cardiac coupling worked only for moms with their own babies, and
only when the duos synchronized smiles and other cheerful social behaviors, researchers report in this month's issue of Infant Behavior and Development. When humans mirror each other's facial expressions, they may switch on specific areas in the brain that tell
the heart when to thump, the researchers suspect. Melding with mom lasts longer than just a few beats, however. Babies who don't tune in with their
mothers are less empathetic as teenagers, according to previous
work from the same lab. Premature infants or those whose mothers have postpartum depression may be most at risk for losing this social skill because
they miss out on early opportunities to interact with mom.
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The Ultraviolet Glow of Newborn Stars
Sometimes your own star gets in the way of understanding the birth of others. In particular, astronomers would like to see the Milky Way's star-forming
regions emit ultraviolet radiation known as Lyman alpha because it's expected to be both strong and a key diagnostic of conditions in stellar
nurseries. Lyman alpha arises from hydrogen at a wavelength of 1216 angstroms (121.6 nanometers), but sunlight with the same wavelength illuminates gas
that streams into the solar system from beyond, obscuring the view. Fortunately, in 1977, NASA launched the twin Voyager spacecraft—their paths are shown here—and both are escaping
the sun's glow: in mid-November, Voyager 1 was 118.9 times farther from the sun than Earth is; for Voyager 2, the comparable figure was 96.9, still
more than twice as far out as Pluto. As astronomers report online today in Science,
the Voyager spacecraft have now spied Lyman-alpha emission from star-forming regions in the Milky Way. Because the properties of these nearby nurseries are known, the feat will help astronomers better understand conditions in far-off star-forming
galaxies—where, ironically enough, Lyman alpha is easier to detect because the expanding universe redshifts the radiation to longer wavelengths
so that sunlight doesn't muck up the view.
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Wasps Spot Familiar Faces
Wasps can recognize faces much like many apes do, researchers report online today in Science. The team taught paper wasps (Polistes fuscatus), whose faces sport distinctive brown and
creamy markings, to associate certain wasp mugshots with safety and others with danger in an electrified maze. The buzzers flew to safety quicker and
with fewer errors when a kind face led the way, the team found. Closely related, but much less social, wasp species couldn't achieve that same feat of
recognition. Still, the paper wasps weren't flawless. When the team plucked the antennae off the heads of photographed bugs, the ability of the wasps
to distinguish one insect from another dropped—as if the critters had been missing a nose.
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Urban Bird Behavior May Divide a Species
Humans aren't the only species to rapidly adapt to urban hustle and bustle. A new study reveals that when European blackbirds (Turdus merula) move from their native forest into the city, they migrate shorter distances than their country cousins—a
behavioral change that could eventually split the populations into separate species. Researchers studied 168 blackbirds along a 2800-kilometer
path in and around seven cities from Spain to Estonia. When blackbirds eat and drink throughout Europe, different atomic varieties of hydrogen become
incorporated into their beaks and feathers, which give clues to their migration patterns. The data revealed that urban blackbirds in northern Europe,
which started moving into cities in the 1930s, stay closest to home during the winter. Meanwhile, their forest-dwelling counterparts still take to the
wing each year for warmer climes, traveling to southern Europe or as far as northern Africa, the team reports online this month in Oikos. Cities
tend to stay warmer than the countryside and there's lots of food within easy reach -- factors that may keep urban birds lazing about town. The
migratory divide could explain genetic differences that have already arisen among the urban and rural blackbird populations -- a possible first step to
a species split.
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Short Chromosomes Linked to Fatigue in Elderly
Short of breath? Short chromosomes may be to blame. A new study of elderly twins finds that those with longer DNA than their
siblings retained more strength and physical endurance past age 70.
Those with the longest chromosomes compared to their twin showed the biggest advantage in self-reported ability to climb stairs, run, and lift weights.
Chromosomes shrink naturally with age as cell division chips away tiny DNA fragments from the tips of chromosomes, called telomeres. Genetics may
determine telomere lengths at birth, but each person loses DNA at a different rate. Environmental risks such as smoking and stress appear to accelerate
the process. Previous studies have linked shorter telomeres with age-related diseases and mortality. The new work, published in an upcoming issue of Mechanisms of Ageing and Development, suggests that telomere length tracks the subtle decline of fitness with age—well before disease
strikes. Whether telomere shrinkage causes or merely reflects bodily aging, however, remains a mystery.
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She Just Lights Up
The great Andromeda Galaxy owes a bit of its beauty to a dalliance with another galaxy billions of years ago, according to new data gathered with
NASA's orbiting Hubble Space Telescope. Lying 2.5 million light-years from Earth, the Andromeda Galaxy is the closest giant spiral to our own and the
largest member of the Local Group, the collection of several dozen nearby galaxies that includes our Milky Way, which ranks number second largest. The
new observations reveal that Andromeda—shown here in infrared (yellow and orange) and x-rays (blue and white)—experienced a rash of star formation in its outermost disk 1.5 to 3 billion years ago, as reported in a
paper in press at Monthly Notices of the Royal Astronomical Society. The likely trigger? Spiral galaxy M33—the Local Group's third largest galaxy, 2.8 million
light-years from us—which swung by Andromeda at the time and experienced its own starburst, suggesting each galaxy's gravity caused gas in the other
to collapse and create new stars.
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More Than a Pretty Face?
Ralph Lauren model Filippa Hamilton is glamorous, but is it physiologically possible for her
hips to be smaller than her head, as a recent ad showed? And how can
62-year-old supermodel Twiggy still look so fabulous? Digital touch-ups of celeb photos might fool someone quickly glancing at Cosmopolitan, or convince teen girls that Hamilton's 17-inch hips are
feasible. When pressed, however, humans are pretty good at telling when a body looks unnatural. To see if a computer could do the same, researchers
recruited 390 volunteers and asked them to look at 468 pairs of original and touched-up photos they had found online and rate each pair on a scale of
one to five on how altered they thought it was. The researchers then created a computer metric that measured parameters like color, blur, and cutting
of unsightly areas in the doctored photos. When they compared their metric's assessment of the photos against the volunteers' assessments, the two were
statistically similar, the researchers report in the Proceedings of the National Academy of Sciences today. A metric like this one, the
researchers hope, might help publishers weed out false advertisers.
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Whirlybirds
City pigeons may be jeered as flying rats, but aloft they're more like helicopters. That's the upshot of a new study of pigeons making aerial turns.
The investigators netted common pigeons, Columba livia, in a parking garage, and aimed high-speed cameras at them as they slowly turned a
corner. From the videos, the researchers then calculated the aerodynamic forces the birds produced to keep themselves aloft and moving. Unlike a rocket
that simply swivels its jets, a pigeon doesn't turn by redirecting the forces it generates relative to its body. Instead, the bird realigns those
forces by rotating its entire body, primarily by tipping its wings into the turn. A helicopter uses the same tipping strategy, lowering its nose to
accelerate forward, for example. The study, posted today in the Proceedings of the National Academy of Sciences, also found that the
turning pigeon's upstroke generates lift comparable to that produced by that super-aerialist the hummingbird—not bad for a laughingstock of the avian world.
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Virgin Lizards Get Picky
Female common lizards (Zootoca vivipara) get pickier with experience. Virgins will mate with almost any male. But the second time around, some favor males with more diverse genes, according to a study in this
month's issue of Behavioural Processes. This "trading up" helps moms gather a diversity of DNA, raising their chances of producing healthy
offspring. Most only birth young two or three times during their lives. So, to make good on the costs of pregnancy, female lizards need to choose the
father's genes wisely. At first, they may gamble on a male with less diverse genes to increase the chance of pregnancy. But after some of her eggs have
been fertilized, she can look around for better males. The researchers think the females may recognize genetic variation by sniffing out males' body
odor, a technique other species—including humans—use.
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How to Make a Tank Disappear
For several years, researchers have known that carbon nanotubes are one of the blackest known materials. These tiny scaffolds—which have a structure
like rolled-up chicken wire—barely scatter light. Indeed, some believe the nanotubes are so black that they might make a new type of camouflage—one that conceals anything as a flat black blob. To test the idea, scientists etched a picture of a tank onto a silicon surface (inset). On its own,
the three-dimensional object was clearly visible because light scattered and reflected off the tank's features, as it does with all everyday objects,
black or otherwise. However, when the researchers coated the tank with nanotubes, the etching appeared to vanish, as though the surface was
perfectly flat. Such camouflage, described in a paper published this week in Applied Physics Letters, wouldn't actually blend an object into its
surroundings. But it would turn anything into a spooky silhouette, like a black cut-out.
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The World's First 'Invisible' Couple
It's easy to spot a committed pair of gibbons or swans: Both halves of the couple frequently hang out together. But good luck finding a twosome in a
school of 2500 Xenotilapia rotundiventralis cichlid fish, a 50-millimeter-long, plankton-eating species that swims the tropical waters of Lake
Tanganyika in Zambia. Now, however, researchers say they've hit upon out a way to figure out who's in a steady relationship with whom. The trick has to
do with the fact that females brood young in their mouths, then transfer young to the mouths of males. By studying the DNA of adults and young, the
researchers determined that the female cichlids are probably passing the kids off to their dads. That means, the researchers report online today in Biology Letters, that males and females form the first known "invisible" pair bond—well, invisible to us
at least.
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Toxic Spider Webs Keep Ants at Bay
Spiders are superb artisans, weaving ethereal webs from silk finer than human hair. Now it appears that arachnids also excel at making chemical
weapons. Researchers have found that the golden orb-web spider (Nephila antipodiana), a species common in tropical Asia, coats its silk with a toxic substance to deter hungry ants. The
secret ingredient is a compound known as 2-pyrrolidinone, which is also made by gypsy-moth caterpillars to ward off predatory ants. When the
researchers presented three types of ants with spider-silk "bridges," the insects refused to cross those soaked in 2-pyrrolidinone, the team reports
online today in the Proceedings of the Royal Society. The chemical is probably physically unpleasant to the ants' antennae, which helps the
spiders keep their meals to themselves.
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How Ink Flows
"True ease in writing comes from art," wrote Alexander Pope in the early 18th century. Three hundred years on, however, we might get a little extra help from science—thanks to researchers who have been studying how ink flows from pen to paper. Performing theoretical calculations first, the team devised equations for predicting the spreading of ink from a moving pen. The calculations indicated that there is a balancing act between the roughness of paper, which determines the attraction or "surface tension" driving ink flow, and the ink's friction, or viscosity. To confirm that the math held up in the real world, the researchers performed experiments using an idealized, ink-filled tube as a pen and a fine grid of silicon micropillars as a writing surface. The results, due to be published later this month in Physical Review Letters, could be used in the design of better quality paper—or even surfaces that repel ink altogether. Graffiti artists, watch out.
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Horse Variety Predates Domestication
Today's horses come in a variety of colors and sizes, but don't credit humans. According to a new study, most of these traits existed long before we
domesticated them. As researchers report online this month in BMC Evolutionary Biology, they analyzed the complete mitochondrial genome—the DNA found within cell's energy powerhouses—of 45 diverse horse breeds, looking for clues to the timing of horse domestication. They found that modern horses arose nearly 7000 years ago, a result that agrees with previous studies. The data also show that the ancestor of all domestic horses—which some scientists believed lived as long as 1 million years ago—roamed much more recently, between 38,000 and 93,000 years ago. In addition, more than 70% of today's horse lineages already existed before domestication, suggesting that a large number of wild founder mothers were used to build up the modern horse population.
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Amoeba-Sized Insect Is Missing Some Pieces
You can't shrink down to the size of an amoeba without losing parts of yourself. That's the lesson one researcher is taking away from a microscopic
analysis of the fairy wasp (Megaphragma mymaripenne), which at a mere 200 micrometers in length is one of the world's smallest animals (shown
compared to a paramecium and amoeba above). When the scientist compared the neurons of adult and pupae fairy wasps, he discovered that more than 95% of adult neurons lack a nucleus. The findings, reported online
this month in Arthropod Structure & Development, suggest that while a complete set of neurons is needed to grow, far less are required to
live. And that helps the wasp shrink so small that it can avoid most predators and invade the eggs of other insects.
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Avoid the Blinking Light
Fireflies flash their lights to attract mates, but this bioluminescence is also a magnet for predators. A new study published online this month in Animal Behaviour, however, reveals that, if a meal tastes bad, predators learn to avoid the blinking.
Researchers placed faux fireflies (a flashing green LED) next to either tasty crickets or a toxic firefly species (Ellychnia corrusca), and then
released a jumping spider. Though the spiders initially attacked both insects, those that went after the fireflies quickly learned to avoid the
flashing LED. In the wild, both palatable and unpalatable firefly species often share the same habitat, so if a spider or other predator gets a bad
taste in its mouth, it will begin to shun all flashing lights, to the benefit of both species.
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Icy Europa Looking More Inviting
Scientists analyzing decades-old images with new eyes are seeing signs that Jupiter's radiation-blasted moon Europa may harbor giant under-ice "lakes"
that could sustain life. Europa doesn't lack for the prime ingredient for life: liquid water. The moon has a global ocean hundreds of kilometers deep
that is covered by a layer of ice perhaps 10 or 20 kilometers thick. But a team of glaciologists and planetary scientists report online today in Nature that—judging by the way erupting volcanoes on Earth disrupt their ice caps—huge pools of water must lie as little as 3 kilometers beneath the surface. On Europa, rather than
a volcano, a rising plume of warmer but still solid ice would drive ice melting a few kilometers beneath the surface. And then a briny slush of ice
would rise from the resulting lake and disrupt the surface to form Europa's long-known chaotic terrains of jumbled ice blocks. Direct confirmation of
giant Europan lakes each holding the combined volume of North America's Great Lakes must await radar probing by a multibillion-dollar spacecraft that is
still stuck on planetary scientists' wish list.
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May the (Magnetic) Force Be With You
A spiral galaxy's magnetic field is global, but it likely acts locally to assemble huge clouds of gas and dust that then spawn stars. That's the upshot
of a new study of M33, a nearby spiral galaxy located 2.8 million light-years away in the constellation Triangulum. As astronomers report online today
in Nature, magnetic fields inside M33's six most massive giant molecular clouds—large concentrations of dense gas and dust that give birth to
stars—line up with the spiral arms, suggesting the magnetic fields helped create the huge clouds
and that they regulate how the clouds fragment to form new stars. Although this finding pertains to M33, it likely extends to other spiral galaxies,
too—including our own, which we'll never get to see from the outside.
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Flexible Ears Help Bats Tune In
Bats navigate by bouncing sounds off of objects (an ability known as echolocation), so perhaps it's no surprise that
their ears work a lot like mini-radar dishes. Using a high-speed camera (tracking reflective landmarks on the bat's ear, as seen above) and 3D digital modeling, researchers have shown that bats bend their ears in various directions to listen for the echoes of their ultrasonic
calls. Upright ears capture high-quality echoes from objects ahead, while ears bent downward and backward hear echoes from more directions but not as
well. Reporting online this week in Physical Review Letters, the team suggests that bats tune their hearing to specific tasks. Bent ears are
better for sweeping the area for potential prey, such as moths, or for predators like owls, while upright ears could zero in on prey when bats dive for
an attack.
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The Fastest Spinning Normal Star
How fast can a star spin? Our sun rotates at a leisurely 2 kilometers per second, but now astronomers have discovered that a star in another galaxy spins 300 times faster—with a record-breaking speed of 600 kilometers per second. At that velocity, an airplane could circle Earth in little more than a minute. The star, named VFTS 102, is hot, blue, and young, residing in the Tarantula Nebula, a huge star-forming cloud of gas and dust 160,000 light-years away in the Large Magellanic Cloud, the brightest galaxy that orbits our own. As the astronomers will report in a future issue of The Astrophysical Journal Letters, VFTS 102 spins faster than any other normal star ever measured; the only stars known to spin faster are dead ones called pulsars. In fact, a pulsar seems to be fleeing from the fast-spinning star, suggesting the two were once a pair that split up when a companion star exploded and became the pulsar we see today. Before the explosion, the companion star may have dumped gas onto VFTS 102, spinning it up to extreme speed the way falling water makes a water wheel turn. If the star spun just 20% faster, the centrifugal force would fling it apart.
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Shrimp Massacre at Coral Point
Call them the Bonnie and Clyde of crustaceans. Put three or four cleaner shrimp (Lysmata amboinensis) in a tank together and after a month only
two will remain, the survivors having killed the others off during the night. According to a study published today in Frontiers in Zoology, the
shrimpicide happens because the crustaceans—which feed on fish parasites and dead skin cells near coral reefs in the Indo-Pacific region and the Red
Sea—grow slowly if there's too many of them in a tank. The more shrimp, the less likely they are to molt, as molting makes them more vulnerable to
attack. By killing off the others, a mating pair frees itself up to molt—and thus grow—as frequently as possible. And in shrimp, larger body size means more eggs laid, and a higher number of offspring. Who may then grow up to do some
killing of their own.
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Blue Light Turns an Octopus Red
One thousand meters under the sea, where the red wavelength of sunlight doesn't penetrate, red organisms are effectively invisible. But things are
trickier in the middle ocean depths, between 600 and 1000 meters, where sunlight can still reveal the silhouettes of colorful sea creatures. So a
couple of mid-ocean-dwelling cephalopods—the animal class including octopuses and squids—have come up with a flexible strategy: Start out
transparent, but change colors when certain predators come around.
In a new study reported online today in Current Biology, researchers witnessed this behavior in the octopus Japetella heathi (shown) and
the squid Onychoteuthis banksii. They exposed the creatures to a beam of directed blue light, as might come from certain bioluminescent
predators, as well as to other stimuli such as passing shadows. When the blue light hit them, the cephalopods contracted muscles that stretched their
pigment-containing cells, turning their skin red. In the wild, this quick blush hides the cephalopods from their predators, as red objects are
imperceptible under blue light. Thus, J. heathi and O. banksii stay invisible, even though they're no longer transparent.
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How to Tame Lightning
Who at school didn't like to play with a Van de Graaff generator? Wind it up, put a finger close to the metal shell and—zap!—a spark jolts across
the gap. Now imagine the length of that electrical discharge isn't a few millimeters, but 60 meters. That's the accomplishment of a team of electrical
engineers, which has developed a new way to create electrical discharges, or "arcs." As they will report in an upcoming issue of the Journal of Applied Physics, the researchers hooked up a thin, 60-meter-long copper wire to the terminals of a 270-kilovolt electrical supply. When
they turned it on, the wire exploded into several short sections, forming beads of plasma, or conductive gas. These plasma beads grew rapidly until
they formed a channel, allowing the discharge of a striking white arc. The researchers believe this "exploding wire" method, which needs less than 5%
of the electric field required for an arc without an initial wire, could be used to make record-breaking arcs, hundreds of meters long. One application
might be to capture lightning from thunderclouds, to save it from striking manmade objects on the ground.
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Bigger Birds Flee Human Noise
It's no secret that loud human sounds—the roar of traffic and hum of heavy machinery—is bad for birds, since fewer are found near such noisy
areas. But some species, particularly larger birds that sing low-pitched songs, such as western tanagers, especially suffer from man-made cacophony,
scientists report in today's PLoS One. Researchers counted birds and nests in the Rattlesnake Canyon Wildlife Area of northern New Mexico, which
is close to thousands of natural gas wells, many of which are coupled with constantly roaring compressors—think of listening to a motorcycle that's
about 15 meters away. After surveying some 30 species of birds, ranging from black-chinned hummingbirds to mourning doves, the researchers discovered
that it was the larger birds, like the mourning doves and western tanagers that kept away from the noise. Such large birds may be forced out of the
loud areas because the roaring machinery drowns out their lower-pitched songs, making it difficult for them to hear each other, the scientists say.
Smaller birds, such as chipping sparrows, sing in a higher-pitch, and these species weren't as affected, presumably because their melodies can still
rise above the din.
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Nano Car Is World's Tiniest
Sure, nature created motor proteins used in synthesizing chemical energy and flexing muscles. And scientists have come up with synthetic molecules that
do everything from walk down a prelaid path to spin a metal whisker like a helicopter blade. But now researchers from the
Netherlands and Switzerland have outpaced them all. The group fashioned what looks like a molecule-sized car, made of a few dozen atoms, with four-wheel drive. The wheels work like
molecular ratchets to all spin in a common direction when fed a fuel of energized electrons from a scanning tunneling microscope. The only difficulty
is that lots of the cars don't actually work because when deposited on a copper surface they land on their roofs or sides. That, and even the ones
that do drive, don't have much room for groceries.
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A 44-Million-Year-Old Hitchhiker
Talk about a ride gone wrong. This tiny mite climbed onto a spider's back at least 44 million years ago, but the spider stumbled into a glob of sticky
tree sap. That makes the duo the oldest known fossil evidence of hitch-hiking behavior, or
phoresy, in a large group of mites called the Astigmata. Immature mites still use the method to migrate to new habitats—although today, they usually
ride on insects, not spiders. Researchers had tried to study the fossilized mite before, but they couldn't see it clearly through the amber. (It's a
small bump on the center of the spider's back in the color photo above.) To make matters worse, its underside was hidden against the spider. So a team
of biologists, paleontologists, and materials scientists used a method known as high-resolution phase-contrast computed tomography to take thousands of
x-ray images and compile them into a digital model of the two arachnids. At less than two-tenths of a millimeter long, the mite (left image) pushed the
limits of the method. But the resulting images, published online today in Biology Letters, provide enough detail to tentatively identify the
mite and even see the suckers it used to hold onto its ride.
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Millipede of the Seas
What has at least 25 pairs of legs and can turn on a dime? That's a question researchers have been asking themselves ever since they uncovered a
strange set of footprints in the Burgess Shale, a 500-million-year-old fossil field in the western Canadian Rockies. The first analysis of the
comma-shaped and elliptical tracks, reported online today in the Proceedings of the Royal Society B, indicates that they belonged to a marine arthropod called Tegopelte (artist's
impression above), a relation of an extinct group of hard-shelled critters known as trilobites. The size of a loaf of bread, Tegopelte was the biggest
bottom-dweller known from the Burgess Shale. The tracks show that the creature was also speedy and nimble, adding to evidence that it was either a
predator or a scavenger—and therefore a possible rival in importance to free-swimming predators such as the segmented arthropod Anomalocaris, which
were known to have thrived in ancient seas.
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Why Some Male Marsh Harriers Dress in Drag
All's fair in love and war, even among marsh harriers, a bird of prey found in western France. Some male harriers are colored almost exactly like
females, with mainly brown plumage and white heads and shoulders, instead of the overall gray of adult males. It's not because they are immature, as is
the case in many bird species, but because they spend their life in drag, a type of permanent mimicry known in
only one other species of bird. Since some 40% of males in one population of the raptors "dress" like females, scientists surmised that there must be
an advantage. And indeed, true males aren't as aggressive toward these female-mimics, the researchers discovered after setting out decoys in breeding
males' territories. Since they don't have to worry about serious fights with their male neighbors, the female-like males can horn in on the breeding
males' territories and their mates, the scientists report online today in Biology Letters. Intriguingly, the female-plumage-mimics not only look
like females—they even behave like them, too: They attacked the female decoys the scientists set out, while largely ignoring male decoys. They also
attacked the decoys of female-mimics as the female-colored male is doing in the photo above.
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Supercharging the Hubble
An international team of astronomers has turbocharged the Hubble Space Telescope, enabling
it to observe a brightly glowing disc of matter that is being sucked into its galaxy's central black hole. Such discs, known as quasar accretion disks,
are typically about 100 billion kilometers across, and most lay billions of light-years away. So how was Hubble able to observe it? Through a technique
called gravitational microlensing in which the light from a background object is bent by gravity around a foreground object. If scientists can line up
a quasar almost exactly behind a much closer galaxy, they are able to see not one quasar but two or four magnified images of the same quasar—a gravitational lens. (In the image above the more distant
quasar HE 1104-1805 is seen as the two larger images on either side of the smaller yet closer lens galaxy [WKK93] G.) The stars in that lens galaxy
then act like ultra-high resolution telescopes (see the NASA video). The level of detail
involved is equivalent to being able to study individual grains of sand on the surface of the moon while standing on Earth. This enabled the
astronomers to measure the diameter of the accretion disc and plot its various temperatures, providing a new experimental confirmation of how quasars
work.
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Meet the Saber-Toothed Squirrel
Scrat, the fictional saber-toothed squirrel from the Ice Age films, may not be so fictional after all. Researchers have discovered the fossil
remains of a 94-million-year-old squirrel-like critter with a long, narrow snout and a pair of curved saber-fangs that it would have likely used to pierce its
insect prey. The creature, pieced together from skull fragments unearthed in Argentina and dubbed Cronopio dentiacutus, was not ancestral to us
or any living mammal. Instead, researchers report online today in Nature, it belonged to an extinct group called dryolestoids, a cadre of fuzzy
mammals that scurried about in the shadow of long-necked dinosaurs, as in the artist's impression above. The new discovery extends the known record of
the dryolestoid mammals in South America back 60 million years from what was previously known. There were no acorns around at the time though, so Cronopio—like Scrat—would have had to do without them.
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Spider Foreplay
Call it the insect version of foreplay. Like humans, tangle-web spiders (Anelosimus studiosus) engage in playful sexual behaviors that include
courting and mock copulation, usually before the females are mature enough to mate. Researchers have found that the activity keeps females happy;
they're more likely to mate and less likely to attack males when they're finally ready for sex. But
foreplay may come with a cost for males. As the team reports online this month in Ethology, males that invest a lot of effort in fooling around with females may end up exhausted and
thus less competitive when they need to fight rivals for a mate. So, at least for male spiders, foreplay doesn't always pay off.
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First Solar System Leftover
Planetary scientists weren't sure what sort of asteroid they were looking at when the European Space Agency's Rosetta spacecraft flew close by Lutetia
on 10 July 2010. But online today in Science, they report that the 121-kilometer-long asteroid is most likely the first object among the 10,000-plus
known asteroids to be recognized as an intact planetesimal of the sort that glommed together to form the planets 4.6 billion years ago. The tip-off was
its high density, as gauged by the way Lutetia's gravity deflected the passing spacecraft. The rocky body—the largest yet to get a close flyby—seems
to have been just large enough to avoid being reduced to a flying pile of rubble by eons of collisions with other asteroids. The quick look has left
researchers still scratching their heads over the planetesimal's mineralogical makeup, but Rosetta has moved on to bigger things: a 2014 landing on
comet Churyumov-Gerasimenko.
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Cool Reindeer Heads Prevail at the North Pole
Prancing around in fluffy fur coats, reindeer stay plenty warm when temperatures plummet below -50°C, but they can't exactly unzip to cool off after
exercise. To study how reindeer avoid overheating, researchers rounded up nine of the friendliest animals they could find and implanted probes into
major blood vessels in their heads that measured blood flow and brain temperature. Then they let the reindeer run on a specially designed treadmill. At
first the reindeer breathed through their noses, allowing the Arctic air to cool the blood in their sinuses before sending it on to the rest of the
body. But once they started breathing faster, up to 260 breaths per minute, they opened their mouths and panted like dogs, letting the air flow over
their big tongues to cool that blood. When their brain temperature reached a critical limit of 39°C, researchers report today in December issue of The Journal of Experimental Biology, the reindeer switched the blood flow pattern in their noses so that the coolest blood
would go to their heads and cool the brain, a strategy similar to their very distant relative: the African antelope.
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Case Closed on Bat Fungus
A potential bat killer is guilty as charged. Scientists say they've finally fingered the culprit behind the deadly bat disease known as white nose syndrome: the fungus Geomyces destructans. Disease experts had previously cultured the fungus from the white dustings that cover the noses and wings of infected bats
(shown). But it wasn't clear whether the potential pathogen was the main cause of the epidemic, which has spread plaguelike throughout the northeastern
United States, or just a side effect. In a study
published online today in Nature, researchers spread G. destructans samples onto healthy little brown bats (Myotis lucifugus), and all developed tell-tale lesions within
several months. The fungus also seems to pass from bat-to-bat on contact: Close to 90% of healthy bats mixed in with sick cohorts in the lab developed
white nose syndrome in just about 100 days. Effective treatments for this rapidly spreading contagion are a long way off, the group says. Still,
unveiling the killer may make this Halloween a little less frightful for North American bats.
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Killer Whale Spa Vacation
Just as winterbound humans head for tropical spas to get away from the cold, killer whales living off the coast of Antarctica sometimes take a break from their frigid home waters. The first satellite tagging of these 6-meter-long cetaceans at the southern tip of the globe has revealed that all five whales whose tags lasted more than 3 weeks left their normal 2°C waters and headed east of the Falkland Islands to 20°C seas off Uruguay and Brazil. One whale completed a 9400-kilometer roundtrip in 42 days. The whales swam at an ever slower rate the farther north they got, yet they never really slowed down to the speeds they swim at when hunting or taking care of young, suggesting that these trips were not for foraging or reproduction as is typical for whale migrations. Instead, the researchers suggest online today in Biology Letters, the whales go to warmer waters to rejuvenate their skin—something they can't afford to do in colder waters because the process draws warm blood away from their interiors. Seals solve the problem by climbing onto land to molt, but killer whales, lacking that ability, may need to take a trip to the spa.
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Crabs Fist Pump Their Way to Romance
Like ecstatic fans at a baseball game, fiddler crabs (Uca annulipes) do the wave. To attract sparse females (right), small male scuttlers (left) gather in large clumps, frantically shaking their oversized claws—similar to the novelty foam fingers popular at sporting events. But when competition between studs peaks, these spurts of friendly greetings can turn into downright wave-a-thons, a new study suggests. Males tend to wave enthusiastically in big crowds, presumably to stand out from their rivals, but they slow their gesticulating by about 30% when alone, researchers report online today in Biology Letters. Big waves nab females, but they can come at a price: The exertion saps a fiddler crab's energy and can catch the eye of predators, such as small shorebirds like rust-colored ruddy turnstones. Still, it could be worse: Unlike South African soccer fans, these beach invertebrates have yet to discover vuvuzelas.
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An Anti-Aphrodisiac
Think of it as the anti-"Axe effect." Unlike the fragrant body spray some guys douse themselves with to attract women, male plant bugs (Lygus hesperus) deposit something on females that keeps members of the opposite sex away. Now researchers say they've figured out the secret of this sexual deterrent. In the November issue of Animal Behaviour, a team reports the identification of a chemical compound known as myristyl acetate in the male plant bug spermatophore, a capsule containing sperm that is transferred to the female during copulation. When the scientists applied this compound on virgin females, males fled. The "anti-aphrodisiac" doesn't just help the male keep the female to himself; it also prevents other males from wasting their time courting a female that's not going to mate with him. And because plant bugs damage crops across North America, the researchers hope the discovery will lead to new ways to combat the insects without the need for nasty pesticides.
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Humpbacks Make a Comeback
In 1966, at the end of the commercial whaling era, humpback whales in the North Pacific numbered only 1400. But now thanks to the international whaling
ban, researchers say there are at least 21,000 humpbacks,
and possibly even more, according to numbers reported in this month's Marine Mammal Science. The whales were counted during a special 3-year
project, known as Structure of Populations, Levels of Abundance and Status of Humpbacks (SPLASH), which was launched in 2004. An international team of
hundreds of scientists photographed more than 18,000 humpback whale tails, or flukes, from Alaska to Guatemala and from the Philippines to Russia. Each
humpback's fluke is as unique as a human's fingerprint, and bears a one-of-a-kind pigmentation pattern. Researchers determined the whales' current
population numbers by comparing photographic shots of humpbacks in their North Pacific feeding grounds (around the Pacific Rim from California to
Kamchatka) to images taken of the whales in their southern, tropical breeding areas—some as far as 3000 miles away. They derived the 21,000 figure
via further statistical analysis of the photographic data. The humpbacks' strong numbers show that they have largely recovered from whaling, though it
will still take some time for them to reach their estimated historical number of 125,000 individuals worldwide.
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First Look at Marijuana's Genetic Code
Attendees at Burning Man, the famously free-wheeling yearly Nevada art gathering, don't usually take note of new genomic sequences, but they may want to check out a paper published today in Genome Biology. In it, scientists report that they've sequenced most of the genetic code of the fibrous plant species Cannabis sativa. The team's specimen of choice: a marijuana cultivar called Purple Kush. The genome may give researchers new insight into what makes the pot plant so, ahem, popular at folk festivals. Comparing Purple Kush with another popular form of the same plant—the hemp-fiber producing Finola varietal—the group found that one gene critical for churning out the precursors to the chemical that gives pot its kick, tetrahydrocannabinol or THC, had been turned off. Purple Kush plants, in turn, produced little to no cannabidiolic acid, a similar compound found in hemp plants, possibly because these molecules suck up the building blocks needed for THC. Far-out news, even for those who don't inhale.
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Songbirds Stay Cool for Their Kids
Call it the bird version of yoga. Red crossbills (Loxia curvirostra), small, yellow-breasted songbirds hailing from the western United States, keep mellow for the sake of their offspring. During chilly
months when the living gets tough, reproductively active crossbills tend to have fewer stress hormones—or corticosterones—churning through their
veins than their nonrambunctious counterparts, researchers report online today in Biology Letters. This absence makes sense: Stress hormones can
give critters a survival edge by, for instance, helping birds and other animals tap their sugar stores. But this stress response is also inherently
selfish. Birds with too much corticosterone often abandon their nests, leaving offspring to the elements. Crossbills may thus dampen the flow of stress
hormones to ensure that their chicks survive, risking their own health in the process. If only they could learn the warrior pose.
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The Physiology of Piranha War Cries
When Jaws swims in for the kill, it's to the foreboding music of John Williams. But piranhas sound their own drumbeats. Red-bellied piranhas (Pygocentrus nattereri), for example, make barking noises when caught. To figure out how the fish vocalize underwater, researchers observed them
in a tank. The fierce predators made three types of angry grunts: First, when fish stare down their rivals face-to-face, they utter rapid calls, much like those same barks. During full fish-on-fish fights, the piranhas tend to emit two low thuds. The scrappy fish
achieved both noises using ultra-fast muscles that beat against their swim bladders, air-filled chambers that aid in flotation, the group reports today
in The Journal of Experimental Biology. The third call is the nastiest; piranhas gnash their teeth while chasing another fish away
from their dinner.
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Europe's Black Death Spawned Modern Plague Strains
These skeletons—excavated in the 1980s from a 14th century graveyard in London—belonged to six of the estimated 30 million people who died from
the Black Death, the plague epidemic that swept Europe between 1347 and 1351. Researchers have now used teeth from the same graveyard—home to some
2500 plague victims—to reconstruct 99% of the genome of Yersinia pestis, the bacterium that causes plague. An analysis of that microbial DNA, published online today in Nature, suggests that Y. pestis strains currently circulating around the world are all descendents of the
medieval strain, which is believed to have killed 30% to 60% of Europe's population. The 14th century genome closely resembled those of modern strains
and did not have any obvious unique mutations that might explain its unprecedented virulence. Other factors—such as the population's susceptibility
or the ecology of rodents and fleas, which help spread the disease—were probably responsible for the medieval massacre, the team concludes.
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Doggie Doolittles
Young children often misinterpret a dog's snarling face as a smile, which may be one reason why kids suffer a high number of dog bite injuries. But youngsters 6 to 10 years of age have no trouble understanding the threat in a dog's aggressive bark, researchers report in the current issue of Applied Animal Behaviour Science. The scientists tested 30 children and ten adults, asking them to judge a dog's emotions by listening to its barks in three different situations: alone, facing a stranger at a gate, and when playing. Lonely barks are high-pitched and slowly repetitive, aggressive ones are deeper and fast, and happy barks are slow and rough. Only adults and 10-year-old children correctly understood the playful bark, and only adults and children ages 8 through 10 had no trouble recognizing barks that were lonely. But adults and children of all ages (and even kids whose families did not own dogs) scored correctly on the aggressive barks. Thus, children encountering strange dogs should ignore their facial expressions, the scientists say, and instead listen to what they have to say.
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Crickets Risk Their Lives for Mates
In the insect equivalent of fighting a duel to protect a lady's honor, male crickets risk their lives to safeguard their mates from danger. Field
crickets (Gryllus campestris) snuggle down in burrows either on their own or with a mate. When pairs hang out outside their holes, males tend to
sit farther away from the entrance, letting females stay closer in. That makes it easier for the buzzing females to duck away from oncoming predators
like magpies; males, however, become an easy lunch. Still, the bugs are no knights in shining armor, researchers report
online today in Current Biology. Males that stick close to females are savvy guards, chasing away other would-be suitors, claiming more mating
opportunities for themselves. So for crickets, at least, it pays to be a gentleman.
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Whisper While You Lurk
If you want to upset a rival, try whispering. That's a piece of advice that seems to work for dark-eyed juncos, a small, grayish sparrow common in
North American forests. Males of this species are more likely to tick off other males when they chirp a soft, complex song than when they blast a loud, territorial song, according to research published this month in The American Naturalist. Males that heard a recording of the quiet song actively searched for the offending male, an encounter
that could lead to a fight in the wild, especially during breeding season. Males that heard the loud song, meanwhile, often ignored it. Whispered songs
are usually meant for females during courtship, the researchers say, so when another male hears it, he thinks someone is trying to steal his mate right
from under his beak.
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Dark Ice on a Hot Planet
NANTES, FRANCE—Despite basking in the sun's fiery glow, tiny Mercury, the innermost planet in our solar system, is probably home to extensive ice fields. Twenty
years ago, radar observations from Earth revealed small, highly reflective areas close to Mercury's poles, suggesting the presence of ice. Now, NASA's
MESSENGER spacecraft, which has orbited Mercury since March, has confirmed that these radar-bright patches neatly coincide with deep crater floors near
the poles that never receive any sunlight at all. This new color-coded photo mosaic of Mercury's south polar region, presented here today at a joint
meeting of the European Planetary Science Congress and the Division for Planetary Sciences of the American Astronomical Society, shows these "freezer"
areas as dark blotches. According to MESSENGER instrument scientist Nancy Chabot of the Johns Hopkins University's Applied Physics Laboratory in
Laurel, Maryland, a full one-fifth of the region within 200 kilometers of Mercury's south pole is in permanent shadow. "It's all consistent with there
being water ice," she says.
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Why Female Lemurs Sleep Around
Researchers have turned the tables in the battle of the sexes. In an attempt to figure out why female mouse lemurs (Microcebus murinus)—a tiny nocturnal species native to Madagascar—mate with multiple males, scientists overfed some females from birth, causing them to plump up larger than the males. The team assumed that the females bred with several partners because they were being sexually harassed, but even though the plus-size ladies were able to defend themselves from unwanted amorous advances, they still shacked up with multiple males every night. In fact, they had more encounters with males than did females who were unusually small, the researchers report online today in the Proceedings of the Royal Society B. Either a polygamous lifestyle confers some unknown evolutionary advantage for females, the team concludes, or girls really do just want to have fun.
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Irrigation Raises Sea Levels
Melting glaciers and icecaps aren't the only things raising sea levels—so is watering your lawn. According to a study published in Geophysical Research Letters, irrigation and other ground water extractions pull immense volumes of water from deep underground and dump it into
the oceans via runoff into streams, rivers, and other waterways. Using information gathered worldwide and then extrapolating known trends to regions
where data is sparse or missing altogether, one researcher estimates that, over the last century, humans pumped more than 4500 cubic kilometers of
water from the ground—enough to boost sea level by 12.6 millimeters, or more
than 6% of the overall increase measured during that period. In recent years, when ground water extractions have skyrocketed, the contribution was even
larger: From 2000 to 2008, humans pumped on average about 145 cubic kilometers of ground water from aquifers each year—enough to raise sea levels by
about 0.4 millimeters annually, or about 13% of the measured amount during that interval. Of the remaining 87% of sea level rise, some studies suggest
that about half results from the melting and runoff of land-based ice, with the other half stemming from the thermal expansion of the oceans due to an
increase in their temperature, particularly in their surface waters.
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Asteroid Vesta Exceeds Expectations
The 529-kilometer-diameter asteroid Vesta is
revealing even more geologic diversity than scientists had expected. They knew that a collision with another asteroid had splashed off three kinds of
rock that still land on Earth as meteorites. And Vesta's overall spectral color, as returned by NASA's orbiting Dawn spacecraft, matches that of these
Vesta meteorites, Dawn team members reported today at a planetary science meeting in Nantes, France. But rather than a monotonously uniform surface
homogenized by impact cratering over the eons, the first up-close look at the asteroid reveals a full palette of mineral "colors" (mapped here in false
color reflecting the wide range of rock compositions). Researchers will now have to sort out how more than 4 billion years of impacts—including one at
the south pole that nearly destroyed the asteroid—reshaped Vesta after it developed a crust, mantle, and core much like Earth's.
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Aspen in Space
NANTES, FRANCE—For an extraterrestrial skiing experience, Enceladus is the place to go. Parts of this small, icy Saturnian moon are covered with a thick layer of
extremely powdery snow, according to a presentation here today at a joint meeting of the European Planetary Science Congress and the Division for
Planetary Sciences of the American Astronomical Society. Consisting of particles just a few micrometers in size (creating the halo in this artist's
impression), the snow has been accumulating over millions or even tens of millions of years. Last year, scientists predicted that some of the material
spewed out into space by the icy geysers at Enceladus's
south pole would slowly fall down to certain areas on the surface. Detailed measurements by NASA's planetary probe Cassini, presented at the meeting,
have now revealed the predicted snow fields, which measure up to 100 meters thick. They betray their presence by their conspicuous bluish color and by
softening the outlines of buried craters and canyons (inset). But prospective skiers should take care not to launch themselves into space: the gravity
on tiny Enceladus is just 1% that of Earth.
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Finger Drawings From a Prehistoric Preschool
Most preschoolers get scolded for writing on walls, but kids living 13,000 years ago were encouraged to scribble, at least in caves. Among the prolific
paintings and other art in the 8 kilometer-long Rouffignac cave system in southwestern France are a number of unusual markings known as finger flutings, which are
made by people dragging their hands through the soft silt that lines the cave's walls. By analyzing the finger flutings of modern humans, researchers
discovered that the ratio of the distance between the three middle fingers indicate that
many of the cave artists were very young children, one as young as 2 or 3 years old. The researchers were also able to tell the children's genders from the shape of the fingers. Some of these flutings were too steady for a toddler,
suggesting that an adult guided the child's hand while teaching him or her, the researchers will report this weekend at the archaeology of childhood
conference in Cambridge, U.K. Since the children's drawings seemed to be concentrated in one chamber, the researchers believe that the alcove may have
been a sort of art school. And some of the drawings were high on the walls and on the ceiling, suggesting that the children were lifted.
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NASA Mission Finds Fewer Near-Earth Asteroids Than Expected
Bad news for little princes—there may be fewer Earth-neighboring asteroids for them to live on than thought. According to results released today by NASA's Wide-Field Infrared Survey Explorer mission, an infrared satellite that's been keeping its eye on asteroids zipping within 200 million kilometers of Earth's orbit, there are close to 20,000 near-Earth asteroids between 100 meters and 1 kilometer in diameter (shown on left). That's down from old guesses of about 35,000 (right). And nearly 15,000 of those rocks, which are big enough to crush an entire city, have yet to be discovered. The researchers also confirmed that astronomers have identified more than 90% of the nearly 1000 big asteroids of the dino-extinction variety. That's too late for Tyrannosaurus rex but perhaps not too late for us.
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Freeloading Wolves
The wolf pack is often pictured as the model of cooperative hunting, but not all gray wolves (Canis lupus) work together to bring down their
prey. Some are freeloaders, according to a paper published today in Behavioral Ecology. Researchers studying wolf packs in Yellowstone National
Park have found that the group's kill success rate does not increase as the number of wolves grows; instead, it levels off once there are more than
four wolves. That seems to be because larger packs include freeloaders, which are
almost always those wolves that aren't breeding and thus don't need to risk their lives to feed pups. The freeloading wolves may appear to be
cooperating, but they actually do very little until the kill is made, say the authors. In that way, they're like members of a large family joining
together for a Sunday dinner—most of whom show up to eat, but don't bring home the bacon.
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Coloring in Prehistoric Bugs
Fans of prehistoric sketches can now color in their favorite ancient bugs with less guesswork. Modern insects from beetles to butterflies are famous
for their metallic hues. These intricate and often iridescent color patterns stem from tiny structural tweaks along the critter's outer exoskeletons,
such as alternating layers of ultra-thin tissue that bounce light in different directions. Many fossil beetles are similarly colorful, but scientists
weren't sure how the fossilization process may have changed their tints. To get at this color conundrum, researchers examined the nanostructures of old
bugs, dating from about 15 million to 50 million years ago, under the microscope. Sure enough, many of the beetles
had different colors than their exoskeleton structure seemed to indicate, the group reports online this week in the Proceedings of the Royal Society B. They conclude that molecular changes during fossilization likely
pushed the beetles' coloring toward the red end of the color spectrum, turning a normally yellow beetle more orange, for example.
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In a Scrape
Icebergs are scraping the sea floor of Antarctic waters more than ever, much to the detriment of bottom-dwelling creatures. The change comes because
seasonal ice in the Antarctic doesn't last as long. Icebergs that break off from glaciers onshore are driven by winds and currents into shallow waters.
At Rothera station on the West Antarctic Peninsula,
the so-called "fast ice" that forms each winter lasts, on average, about 5 days less per year than it did a quarter-century ago, researchers from the British Antarctic Survey report online today in Nature Climate Change. Accordingly, the number of iceberg scrapes (see image) on
the sea floor there has increased substantially. Only half as many colonies of Fenestrulina rugula, a filter-feeder that lives on rocks on the
sea floor, survive to sexual maturity—the first demonstrable effect of climate change on the Antarctic seabed, the researchers
say. Because about 80% of all marine species found around Antarctica live on or just beneath the sea floor, and because many reach sexual maturity more
slowly than F. rugula does, the new finding bodes ill for ecosystems in the Antarctic shallows.
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Place Your Bets on the Falling Satellite!
Sometime on Friday, a 6.5-ton satellite the length of a small bus will plunge back to Earth. Deployed from the space
shuttle Discovery in September 1991 and decommissioned in December 2005, the Upper Atmosphere Research Satellite (artist's concept in image) measured chemical
compounds found in the ozone layer, wind and temperature in the stratosphere, and energy streaming from the sun. According to NASA analyses, as many as
26 components weighing a total of 532 kilograms could survive reentry and strike Earth at scattered sites from 500 kilometers to nearly 1300 kilometers
downrange of where the satellite first enters the atmosphere. Potential crash sites lie anywhere between 57° N (about the latitude of Sitka, Alaska,
and Aberdeen, Scotland) and 57° S (a little more than 100 kilometers south of the southern tip of South America). Because Ireland lies beneath the
flight path of the satellite, bookmakers there are getting in on the action: the most likely spot for the craft to crash is the Pacific Ocean, but odds
are about 66-to-1 that any space debris lands on the Emerald Isle. If any pieces strike land, the most likely continents to be slammed are Africa
(9-to-4 odds) and South America (11-to-4 odds), both of which lie fully within the danger zone. Because significant swaths of Asia and North America
lie outside the danger zone, odds of debris landing there are lower, at 3-to-1.
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A Whale Tête-à-Tête in the Northwest Passage
The impassable glaciers of the Northwest Passage through Canada drove 19th century European explorers to madness,
but decades of global warming have created a nice passageway for whales to rush in where adventurers feared to tread. Researchers studying bowhead
whale migration patterns searched through 10 years of data from 122 whales they had tagged with satellite transmitters. They spotted one adventurous
young whale entering the passage from the east in 2002, and another from the west in 2006. But each time, sea ice blocked both whales from crossing
entirely. Then in September 2010, a summer when sea ice was extremely low, two male whales entered the passage from opposite directions, and for a
short time their paths overlapped. For about 2 weeks,
they were within 130 km of each other, only 48 hours of swimming for a whale, the researchers report today in Biology Letters. Although their rendezvous shows that it's possible for a whale to cross the passage some
summers, both of these intrepid explorers went home soon after. Apparently they were just saying hello to a population they hadn't seen for millennia.
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A Shield Made of Eggs
Beetles and Lego castle builders both know that stacking is the key to a strong fortress. The seed beetle (Mimosestes amicus) plops its shiny
eggs one on top of the other to protect the bottommost eggs from parasitic wasps, which drill inside to the yolk and lay their own offspring. The
strategy works: lab studies show that shielded eggs get cannibalized much less often, researchers
report online this week in the Proceedings of the Royal Society B. Wasps, instead, tend to go for the top-most eggs. And they're welcome to
them: As far as the beetles are concerned, these outer shield eggs are duds, good only, perhaps, for protection. In fact, the beetles pump so few
nutrients into these outer eggs that many of the wasps infesting them wind up starving. Try building a Lego castle that can do that.
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A Crystal a Million Years in the Making
First discovered about a decade ago, the largest known cave crystals—single hunks of gypsum as much as 11 meters long, 1 meter thick, and weighing
55 tons—could have taken up to 1 million years to grow, a new study suggests. The cavern in the Mexican silver and lead mine where the crystals were
found was filled with mineral-rich waters until 1975, when it was drained to provide miners with access to new ore veins. Lab tests indicate that the
gypsum hunks crystallized at temperatures between 54°C and 58°C, researchers report online today in the Proceedings of the National Academy of Sciences. By immersing a hunk of gypsum in a sample of the cave's waters and using a microscopic imaging
technique that allowed the scientists to directly measure crystal growth, the team found that at 55°C, near the temperature at which the crystals would
have grown most slowly, it would take around 990,000 years for a gypsum crystal 1 meter in diameter to form.
At water temperatures of 56°C, the same crystal could have formed in about 500,000 years.
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Massive Storm on Alien World
Extreme and irregular variations in the brightness of a nearby brown dwarf suggest the star's atmosphere is wracked with storms. Using data gathered by an infrared camera during a
survey of such stars, astronomers have found that the brightness of a brown dwarf—dubbed 2MASS 2139, which lies about 47 light-years from Earth—varied as much as 30% in less than 8 hours. That radical variation could be best explained by brighter and darker patches of its cloudy atmosphere (see
image) rotating into view as the star spins on its axis, the researchers contend. Or, as they will report later this week at the Extreme Solar Systems II conference in Jackson Lake, Wyoming, it's possible that bright spots
represent brief glimpses of deep, hot layers of atmosphere through dark clouds composed of silicate and metallic dust grains. If the variations are
caused by massive storms similar to those that occasionally rage on Jupiter and Saturn, then the storms are larger than any yet discovered on a planet.
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King Crab Invasion
The king crab Neolithodes yaldwyni is invading. Once confined to the deep ocean surrounding Antarctica, the crustacean has begun to creep up the
continental shelf. Using a remotely operated vehicle, scientists have found
large numbers of the crabs hundreds of meters higher than previously known, the team reports online this week in the Proceedings of the Royal Society B. As the crabs encroach into new territory, they're wreaking havoc on
other sea life, wiping out up to three-quarters of the local species of sea floor dwellers. Because waters in and around the sea floor basin where the
crabs were spotted have been warming about 0.01°C per year in recent decades, the basin's crabs—which now number more than 1.5 million—and their
progeny are poised to climb even higher in the next 10 to 20 years, the team estimates. If the crabs indeed proliferate and move to shallower waters,
their effect on sea floor ecosystems around Antarctica—which have evolved for millions of years without shell-crushing predators such as crabs, sharks,
and bony fish—could be devastating.
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Meteorites Brought Gold to Earth
Gold and platinum shouldn't be rare on Earth—they shouldn't be here at all. Or at least, they shouldn't be in Earth's crust. These elements, along
with iridium and similar metals, love iron, and thus they were sucked into our planet's molten iron core soon after Earth formed. So where did all of
the material for our fancy jewelry come from? According to high-precision measurements of two isotopes, or atomic variants, of tungsten in
4-billion-old rocks from Greenland published online today in Nature, precious-metal-bearing meteorites struck Earth around this time,
coating the planet in a veneer containing gold, platinum, and other elements long after their native counterparts had disappeared into the planet's
core. Proof positive that your bling really is out of this world.
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Brittle Gold
Gold wire thick is enough to hold in your hand bends and stretches, making it useful in electronics equipment. But
stretch gold too thin—to less than 20 nanometers in diameter—and it becomes brittle, researchers report this month in Advanced Functional Materials. When the team zoomed in for a closer look at the single-crystal gold wires it
had been stretching, it found that the brittle-broken single crystals hadn't been so single when they snapped. They had spontaneously "twinned." Twin
crystals share some atoms but their overall crystal structures are offset from each other (as shown by the yellow lines in the picture above). When the
gold wires stretch, entire groups of atoms slip into different positions to relieve the stress and create twins. As the gold wire stretches more and
more, it twins again and again. It eventually breaks, in a brittle way, along a plane between twins. This discovery may force engineers to treat gold
wires in nanoelectronics more gingerly, or substitute a different material entirely.
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The Invisible Mouse
What goes on inside a mouse's brain? Even though researchers have developed ways to make neurons fluoresce, they have a hard time observing them in an
intact animal. Enter a new chemical cocktail named Scale. Researchers serendipitously discovered that a mixture of urea, glycerol, and soap
makes synthetic membranes transparent. When they tried the mixture on a developing mouse fetus, they found that it removed all of the pigment from the
cells, rendering them completely transparent (right). The technique,
described online this week in Nature Neuroscience, allows scientists to see fluorescent neurons buried several millimeters in the brain (inset).
But no need to worry about invisible mice creeping into your kitchen; Scale is too strong to use on a living animal.
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Cane Toad Carnage
The biggest danger for a cane toad (Rhinella marina) egg isn't a predator of a different species; it's a cane toad tadpole. The tadpoles not
only seek out and eat eggs, they also release chemicals into the water that stunt the growth of developing cane toad embryos, new research reveals.
It's all part of an intense competition for resources. To study this phenomenon, scientists kept cane toad eggs with tadpoles in tanks and
separated them with a mesh divider. When the eggs hatched, the new tadpoles were 11% shorter and 45% lighter than their siblings that
developed in eggs that were kept alone. Additionally, the survival rate of the tadpole-exposed eggs was 40% lower, the
team reports today in Biology Letters. The researchers haven't isolated the chemical responsible for dwarfing and killing the cane toads, but
that's their next step. Such a compound could help control populations of cane toads in Australia, where they are
considered an invasive species and threaten the diversity of native reptiles.
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Brad Pitt Is Not an Animal
The amygdala is a brain region best known for regulating emotion. But a new study reveals a previously unknown talent: recognizing animals. Researchers
asked 41 epilepsy patients who'd had electrodes implanted in their brains in preparation for surgery to watch a computer monitor as 100 photos of
people, animals, landmarks, and objects flashed onscreen. After analyzing the responses of 1445 neurons in the amygdala and neighboring regions, the
team reports today in Nature Neuroscience that the right amygdala (but no other region) contains neurons that respond specifically to photos of animals. These neurons
fired in response to animals but not people (not even a young Brad Pitt, as shown above), regardless of the angle or distance from which the shot was taken, and as a
group they showed no preference for any particular category of animal, be it bird or mammal, dangerous, or potentially delicious. The researchers
speculate that these responses reflect the importance of animals as both predators and prey in our evolutionary past.
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The 'I' in Ant
Ants are renowned for their hive mind: most decisions are made by the colony as a whole and not by individuals. But when an ant colony's nest is
destroyed, the insects rely on the advice of individuals, according to a study
published online this week in The Journal of Experimental Biology. Researchers created artificial nests and foraging areas for ten colonies of Temnothorax albipennis ants. After a week, the team destroyed the original nest, forcing the ants to relocate. As the researchers watched the
ants on their house hunt, they noticed that the ants that scouted for good locations to find food headed straight for an alternate nest site that they
had discovered earlier in their travels. The scout ants then recruited other members of the colony to the new nest site. The study, says the
researchers, shows that individuals play a much larger role in ant society than previously thought.
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Diamond Planet Orbits a Pulsar
Astronomers have discovered the densest extrasolar planet yet: A Jupiter-mass remnant of a carbon- and oxygen-rich star that measures no more than
55,000 kilometers across. The odd world, whose density is on average at least 23 grams per cubic centimeter (or about twice that of lead), is probably
crystalline and possibly largely composed of ultradense diamond. The
planet orbits its parent sun—a pulsar, or a rapidly-spinning neutron star that emits an intense beam of radio waves, dubbed PSR J1719-1438—once
every 2 hours and 10 minutes, the researchers report online today in Science. The planet’s orbit measures about 600,000 kilometers across,
only 50% more than the average distance from Earth to the moon. How such a dense planet formed is unclear, the researchers say, but it’s probably
the crystalline vestige of a white dwarf star whose atmosphere was stripped away by the parent pulsar. Most of the pulsars that spin faster than once
per 20 milliseconds are part of a binary star system, but about 30% have no companions whatsoever, the scientists note. Only one other rapidly-spinning
pulsar is known to be orbited by Earth-mass planets—a sign that exotic planets such as this megadiamond are, like their Earthly counterparts, rare
indeed.
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Breathless Caterpillars Await Molting
Four or five times along its road to moth- or butterfly-hood, a caterpillar molts to make room for a larger exoskeleton. How does the bug know when the
moment has arrived? A stressed respiratory system seems to be the cue, according to a study published this week in the Proceedings of the National Academy of Sciences. Researchers measured tracheal tube sizes in tobacco hornworm caterpillars (Manduca sexta
) throughout their development and found that, while the rest of the organisms' bodies grow between molts, the tubes do not. So, at some point in each
stage the caterpillar's body becomes too big for its respiratory system, the bug starts suffocating, and
the resultant low oxygen levels spur exoskeleton shedding. After repeating the process a few times, the larvae eventually reach metamorphosis.
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Star Gulp Gives Black Hole Indigestion
A giant black hole in the constellation Draco bit off more than it could chew. On 25 March, NASA's Swift satellite detected an
x-ray flare when a black hole 3.9 billion light-years from Earth tore a passing star to shreds. The flare arose because friction and gravity roasted the star's
remains and made them glow brilliantly before the black hole swallowed them. Now, as astronomers report online today in Nature, the x-ray data as well as radio observations indicate the fireworks caused a narrow jet of
material to shoot away from the black hole's outskirts. Similar jets emerge from other black holes, but this is the first time that astronomers have
witnessed the birth of one. The black hole in Draco resides at the center of a far-off galaxy and is about the same size as the 4-million-solar-mass
black hole marking the Milky Way's heart. Although our galaxy's black hole is currently quiet, this discovery means just one wayward star can spark a
spectacle.
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Warmer Eggs, Better Ducks
All that time ducks spend sitting on their nests pays off, and not just by protecting their eggs from hungry foxes.
The warmer a duck egg stays, the stronger the immune system of the duckling that hatches, according to a new study. Researchers incubated the eggs of wood ducks (Aix sponsa) at 35˚, 35.9˚, and 37˚C, temperatures within the normal
range for eggs in the wild. When the eggs hatched, the scientists challenged the immune system of each duckling by injecting it with foreign cells. The
birds that had been incubated at the lowest temperature had the least swelling at the injection site and the fewest antibodies in their blood. That
indicates that their bodies were not as robustly attacking the foreign cells, the team reports today in Biology Letters. In the wild, ducklings
are exposed to pathogens and parasites as soon as they hatch, and small differences in immune function could determine whether the hatchling survives
or not.
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The Secret to Sticky Feet
A faint, fatty residue found in gecko footprints may finally solve the riddle of these lizards' ability to stick to walls and ceilings. Researchers
believed that molecular interactions between the microscopic branching hairs on the gecko's
footpads and the surface to which they clung were responsible for the gravity-defying feats. A team of researchers, however, noticed that the geckos
had footprints; that is, they left behind a slight residue as they walked. Analysis of the residue, published today in the Journal of the Royal Society Interface, showed that it consisted primarily of fats known as phospholipids. These compounds may help protect the
delicate hairs on the gecko's toes, as the hairs never showed any signs of wear. The
lipids might also provide a liquid-like layer that makes the lizard's toes cling better. And that could help materials scientists trying to create an adhesive-free, reusable tape that mimics the geckos' sticky skills.
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Iberian Lynx Not Jinxed by Genetics
A study of ancient DNA has given scientists more hope that the world's most endangered cat species can be salvaged. Habitat destruction and the decline of its main prey, the European rabbit, have caused the population of the Iberian lynx (Lynx pardinus) to plummet below 300 individuals in two isolated areas in Spain. Scientists are trying to help with a breeding program, but some believe a lack of genetic diversity—which leads to inbreeding problems and an inability to adapt to change—may doom the species. Now, a study of DNA found in fossil bones shows that the Iberian lynx has had very low genetic diversity, and presumably small populations, for at least 50,000 years. For reasons that are unclear, it always got by, the researchers conclude in their paper in Molecular Ecology. So if the lynx is lost, they say, don't blame its genes; blame the lack of political will to save it.
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Old Sparrows Are Mocking Birds
If you get too close to an old song sparrow (Melospiza melodia), prepare to be mocked. The birds mimic elements of the songs of those who encroach on their territory—a taunt known as song sharing that says, "I've got my eye on you." Young birds don't take part in this parody, however, according to a study to be published in a forthcoming issue of Behavioral Ecology and Sociobiology. Instead, audio recordings reveal that they sing a random tune. Song sharing often leads to a fight, and the researchers suspect that the youngsters don't do it because they're insecure about their battle prowess. The old timers, on the other hand, know that they can hold their own.
Sounds of Old Song Sparrows
Song 1
Song 2
Song 3
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Tracking Space Weather
Using a newly developed technique that can separate the dim light of a solar flare from the blaze of stars in the background, researchers have, for the
first time, tracked a massive solar flare from the sun all the way to Earth,
they reported at a NASA press briefing today. That coronal mass ejection—or CME, a type of solar flare that hurls prodigious amounts of charged
particles into space—erupted from the sun in December 2008, and only now have scientists developed a way to spot material in a flare throughout its
lifetime. Solar flares are bright as they erupt from the sun, but after the first few hours they diffuse to near invisibility. By the time a typical
CME crosses the orbit of Venus, its material glows only 1 billionth as brightly as the full moon, yet it's still strong enough to damage power grids
and satellites. The new analytical tool, which dissects data gathered by five cameras on a probe orbiting the sun far from Earth, provides scientists
with the ability to track CMEs from the time they burst from the solar atmosphere (top) to the point at which they near Earth (bottom). That capability
will allow researchers to better observe the evolving size, shape, speed, and magnetic field of massive flares and therefore better predict when the
CME will slam Earth and what its effects might be.
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CO2 Makes Fish Dumb
To survive the complex, often-dangerous environment of a coral reef, the colorful reef fish Neopomacentrus azysron has to be a clever fish. Like many intelligent animals, it uses the right and left hemispheres of its brain for different purposes, which allows for quick problem-solving. But this reef fish could be in danger of losing its smarts as levels of CO2 in the ocean continue to rise due to human activity, according to a new study. Researchers raised one set of reef fish larvae in normal seawater and one set in water containing twice as much CO2—the level that the Pacific Ocean is expected to reach by 2100. When the fish grew up, the team put them in a maze. Each fish that had been spawned in the normal water consistently preferred to turn either right or left every time it reached the barrier, a sign of "handedness." But fish that had been spawned in high CO2 didn't have a favorite hand: they turned right or left at random each time they hit the barrier. This loss of handedness, the researchers report today in Biology Letters, may be a sign of other, more subtle developmental brain dysfunctions that might hurt the ability of this fish, and other marine species that could be similarly affected by CO2, to survive in a high-carbon future.
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Baby Penguins Know How to Chill Out
Human babies scream when their meal is a few minutes late, but baby penguins are better at keeping their cool—literally. As almost perfectly round
balls of fluff, king penguin chicks are well-adapted to their cold climate, but when their parents leave to go forage, the babies are left alone
without food for up to 5 months at a time. To study how chicks conserve their energy during this period, researchers surgically implanted data-loggers
into 10 king penguins between 3 to 4 months of age, monitoring the temperature in their stomachs, chest cavity, and fat over a period of about 7
months. The chicks' internal body temperature dropped by up to 15˚C while fasting in cold or rainy weather,
the researchers report online today in Nature Communications. That's a surprisingly large dip for such a big baby bird (10 kilograms); the
Australian tawny frogmouth, the biggest bird previously found to drop its body temperature in response to winter weather, weighs only 500 grams. The
temperature of penguin chicks even seems to drop when they eat a chilly meal: When their parents come back and give them a mouthful of cold,
already-been-chewed fish, the chick's body temp plummets 15˚C.
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Worms Enter the Synthetic Age
Designer proteins aren't just for bacteria anymore. For the first time, scientists have engineered a whole animal to build its proteins with a synthetic amino acid. The early adopter is a microscopic worm known as Caenorhabditis elegans. Researchers had previously tweaked the genome of the Escherichia coli bacterium to code for 21 amino acids instead of the typical 20, and now another group has done the same with C. elegans. To track which of the worm's cells made proteins that utilized this extra, artificial building block, the team tagged it with a glowing cherry-red dye. And sure enough, cells that went synthetic glowed red, the researchers report this week in the Journal of the American Chemical Society. They now hope to create worms with artificial amino acids that can be controlled by light or specific chemicals: a toolkit that would allow researchers to switch specific cells or molecules on and off.
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World's Oldest Wood
Talk about an old-growth forest. Newly described fossils push back the appearance of wood by at least 10 million years. The fossils, including one from 407-million-years-old rocks in France, preserve the remains of stems about 12 centimeters long. The size and arrangement of cells in the cores of the stems, and particularly the presence of long, thin cells (arrows) that span several rings of cells and extend like rays from the center toward the outer rims, are characteristic of wood, researchers report online today in Science. The plants' small size, as well as the presence of thick-walled cells elsewhere in the stems, suggests that wood evolved to efficiently transport water from the soil into the plant. At the time these plants lived, atmospheric concentrations of carbon dioxide were decreasing, which in turn decreased the water-use efficiency of the plants and boosted their need for water, the scientists say. Although the first plants sporting wood were small, subsequent species quickly took advantage of wood's structural strength: In just a few million years, some had attained treelike stature.
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Rover Takes a Deep Look Into Mars
Yesterday, after a 3-year, 21-kilometer journey at top speeds of less than 0.2 kilometer per hour, the Opportunity rover finally arrived at Mars's Endeavour crater. The intrepid explorer had already poked into 11 craters, the largest 750-meter-wide, 70-meter-deep Victoria, and analyzed rocks and soil along 33 kilometers of track. But the geologic story it read there always spoke of an ancient martian wasteland of windblown dunes pocked by the occasional acid-laced puddle. Now that it has arrived at 22-kilometer-wide, 300-meter-deep Endeavour, Opportunity may be on the brink of rock from earlier, more hospitable times in martian history. NASA's Mars Reconnaissance Orbiter has detected clay in rock of the crater rim exposed by the far larger impact explosion that created Endeavour. And the presence of clay tells geologists that water altered the rock under far milder, presumably more habitable conditions than those that produced the rock Opportunity or any other rover has analyzed to date. NASA's $2.5 billion Curiosity rover scheduled to launch this November, if successful, will not likely reach its clay-bearing target in Gale crater until 2013.
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Small Male Squid Pack Big Sperm
Small male squid can't beat their bigger rivals when courting a female, so they resort to a sneakier tactic: deploying their sperm at the last moment.
After a female chooses a large male, he places his sperm packet inside her oviduct and stays with her until she spawns so that no other male has a
chance to mate with her. But smaller males hang out close to the nuptial pair and rush in to mate with her just as she releases her eggs. These
diminutive Romeos place packages of sperm on the outside of the female's body, close to her sperm storage organ, just below her mouth. The sperm thus
fertilize some of her eggs as she deposits them on the sea floor. Although the sneakier males don't inseminate as many eggs as their rivals do, it is
still an effective tactic, researchers report today in BMC Evolutionary Biology. Lab studies also reveal that, despite their size, small squid
make bigger sperm than large squid. That's not because the bigger sperm outcompete the smaller ones; instead, they're large because they have to
withstand the harsh environment outside of a female's body.
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Squawking With Dinosaurs
What was toothless, may have been the size of an ostrich, and lived alongside the dinosaurs? According to a paper published today in Biology Letters, the answer is Samrukia nessovi—an
enormous bird discovered in the 83-million to 70-million-year old strata of southern Kazakhstan. Very little is known about the creature. Paleontologists have only a pair of lower jaw fragments to go on, the larger of which (pictured above) is
almost 11 inches long. Nevertheless, the size and anatomy of the bones identify Samrukia as a unique species of archaic bird which would have
weighed at least 25 pounds—far larger than any of its known contemporaries. That overturns the previously held idea that birds stayed small until
the nonavian dinosaurs died out. In life, Samrukia may have resembled an albatross if it could fly, and an ostrich if it was flightless (two
possibilities envisioned in silhouette in this speculative restoration) though paleontologists have a few more bones to pick before they can be sure.
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Is Mars Weeping Salty Tears?
"I'm going to hear from my colleagues: 'So, you've discovered water on Mars for the thousandth time?' " says planetary scientist Alfred McEwen of the University of Arizona in Tucson. Actually, it's much better than that. Using the most powerful camera ever to orbit Mars, McEwen and his colleagues are reporting the strongest evidence yet for water on Mars that's flowing, not frozen—and the water is flowing today, not a millennium or an eon ago.
At a few spots, the meager warmth of martian summer seems able to coax enough liquid water out of the ground to darken the soil in streaks. The marks, which sometimes number in the hundreds, grow downhill hundreds of meters only to fade with the winter cold. And where there is liquid water, as they say, there could be life.
The newly recognized seasonal streaks are like nothing else on Mars, McEwen and his colleagues reported last March at the Lunar and Planetary Science Conference—a finding that they also publish online today in Science. That's because nothing else—no other streaks or gullies—behaves as if flowing water is forming it today, they say. Seasonal streaks act as if elevated temperatures around the melting point of water ice unleash liquid water. By monitoring the same areas using the HiRISE camera aboard Mars Reconnaissance Orbiter, the team watched the shapes cycle with the seasons. Dark streaks a few meters wide grew from rocky outcrops down steep, equator-facing slopes beginning in the martian spring and continuing until the early fall (as in the animated HiRISE imagery above). In the colder seasons, the streaks faded away.
Measurements made by another orbiter show that areas marked by seasonal streaks are basking in solar warmth like sunbathers trying to catch the maximum rays on a cool spring day. As a result, surface temperatures rise to within 20°C to 30°C of the melting point of ice when seasonal streaks are forming. Given that the Phoenix lander found abundant salts in martian soil that can lower the freezing point of any water present, the observed near-freezing temperatures look sufficient to allow flowing, briny water on or just beneath the martian surface.
"This may be our best evidence yet of liquid water emerging on the surface of Mars," says planetary scientist Oded Aharonson of the California Institute of Technology in Pasadena. Flowing water is not yet proven, he says, but "I would bet my bike on this, and probably my car, but I wouldn't bet my house on it."
"It's exciting," says planetary scientist Joseph Levy of Portland State University in Oregon. "Mars looks more like the Dry Valleys of Antarctica every
day." That's the largely ice-free part of the continent where trickles of summertime meltwater can dampen slopes and support a hardscrabble microbial
population, including algae, just beneath the surface. A damp subsurface is where life is most likely to be found today on Mars, notes McEwen. "Now we
see perhaps some groundwater is coming to the surface. It gives us a location to focus on" as NASA continues to "follow the water" in search of martian
life, past or present.
*This article has been changed to reflect that Alfred McEwen is at the University of Arizona.
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One Ribbit Too Many
Female animals flock to the ridiculous: the gangly antlered moose, the blue-bottomed baboon, and the garish peacock. But a new study suggests that
túngara frog (Physalaemus pustulosus) females from Latin America keep that machismo posturing from turning too bizarre. Males of this species
serenade their would-be mates late into the night, mixing high-pitched "whines" with short "clucks." Females, in turn, prefer the suitors that cluck
the most but only up to a point. Males, it seems, overdo their arias during long song-a-thons by continuously trying to one-up rivals, and their
amphibian Aphrodites aren't able to follow along.
The more complex the songs get, in fact, the less the ladies can distinguish good from poor singers, researchers report online today in Science. That limitation may stop the frog princes from evolving increasingly elaborate songs, preventing
the inevitable all-frog review of Madame Butterfly. Shortcomings in female perception may similarly slow the ambitious displays of males in a
host of other species, the team suggests, although moose haven't seen to have gotten the message.
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Miniature Radiation Meter
A wee sensor flight-tested onboard the Lunar Reconnaissance Orbiter offers a light, low-power option for measuring radiation from cosmic rays and other
sources that can damage both astronauts' health and space-based hardware, a new study suggests. The device is barely larger than a dime, weighs less
than a paperclip, and requires only 3 bits per second to transfer the data it collects. Yet its radiation measurements fall within a few percent of
those made by a much larger instrument installed on the same probe that is 300 times as heavy and consumes 25 times more power, a team led by
researchers at The Aerospace Corporation in El Segundo, California, reported 14 July in Space Weather. Spacecraft designers could incorporate
the sensor into probes where size, power, and bandwidth are at a premium, the researchers say.
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Science Shot: Dawn Spies a Messed-Up Vesta
Two weeks after settling into orbit around Vesta, the ion-propelled Dawn spacecraft is returning stunning images of the 530-kilometer-wide asteroid.
And boy is it in rough shape. An image presented today at a NASA press conference is the first whole-asteroid portrait returned from a distance of 5200
kilometers. The broad, relatively smooth expanse covering much of Vesta in this view is part of the 460-kilometer-wide crater blown into the south pole
region when the impact of an 80-kilometer asteroid nearly shattered Vesta. Having been created relatively recently in solar system history, this impact
basin has accumulated fewer of the smaller craters that roughen the surface to the north (top of image and in this video). More mysteriously, the region in the north is banded by parallel grooves running
like lines of latitude around Vesta's equatorial region. Planetary scientists modeling a huge impact on Vesta had warned that rocky debris could pile
up in some odd shapes, but nothing like this showed up in their models. Dawn will be dipping to lower and lower altitudes in coming months until it is
just 200 kilometers above the surface.
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Golf Is All About the X (and S) Factor
Golfers can spend years honing their swings, but now it seems there are just a few key traits that separate amateurs from the pros. Researchers used
eight digital cameras to record 3D videos of 10 professional and five amateur male golfers in action. Then, they measured several parameters, including
the "S factor" (tilt of the shoulders) and the elusive "X factor" (rotation of hips relative to the shoulders), which is considered vital for power
generation. Compared with the amateurs, the pros had S and X factors that were greater—often by as much as 10 degrees—and more consistent. Although
previous studies have examined the biomechanics of golf, this latest study, published online today in the Journal of Applied Biomechanics, is
thought to be the first to analyze rotational biomechanics throughout the swing. According to the researchers, the results could help golfers strike
balls harder, with less risk of injury.
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Tree Gliders Are Energy Wasters
Gliding from tree to tree may not be as relaxing as it looks. A number of small mammals, including the colugo—a flying lemur (Galeopterus variegates) native to southeast Asia and the Philippines—get around by climbing up trees and then gliding across the canopies an
average distance of 30 meters. But these animals could save more energy if they just ran on all fours, according to a
study published today in the Journal of Experimental Biology. By attaching small data-logging packs with motion sensors to the backs of four
colugos, researchers found that it takes one-and-a-half times more energy for the animals to climb up a tree and glide from point A to B than it does
for them to move the same distance through the trees. So why do they do it? Perhaps, the researchers suggest, gliding in mammals evolved for survival
reasons: since they feed on canopy leaves, gliding may have protected them if they fell from the branches. It also may have helped them escape from
predators, giving a new meaning to the phrase "fight or flight."
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Juno Takes on Solar System's Heavyweight
At 318 times the mass of Earth and more than twice the mass of all the other planets combined, Jupiter is the undisputed master of the solar system.
But no spacecraft has ever gotten close enough to the gas giant to probe deep beneath its colorful cloud tops to decipher how the planet came together.
NASA's $1.1-billion Juno spacecraft, to be launched on 5 August, will go deep,
very deep. Coming as close as 5000 kilometers to the 140,000-kilometer-diameter gas ball, Juno and it's gravity-gauging system should measure the mass
of any rocky core at the center of Jupiter. Whether it has a core massive enough to have pulled in all its gas is the central question in the debate
over how Jupiter formed. Other instruments will measure water and different key chemical components, probe the inner workings of the powerful magnetic
field, monitor charged particles driving the solar system's brightest auroras, and, of course, return some stunning close-up color images. Planetary
scientists are going to have hold their breath a bit, however: Juno will not arrive at Jupiter until August 2016.
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Earth's Little Buddy
Earth has a new sidekick. Astronomers have spotted
a small asteroid traveling around our sun in the same general path as our planet. The 300-meter-wide rock, dubbed 2010 TK7, is Earth's first so-called "Trojan" asteroid, a class of bodies that gets its name from the
asteroids that orbit the sun at the gravitationally stable points 60° ahead of and 60° behind Jupiter—which, according to astronomical convention,
are individually named after prominent figures from the Trojan War (Brad Pitt excepted). Besides the thousands of Trojans that co-orbit the sun with
Jupiter, astronomers have discovered a handful that co-orbit the sun with Neptune and Mars. 2010 TK7 isn't a threat to Earth. For one thing
it's ahead of us, not behind us. And its current orbit brings it no closer than 20 million kilometers or so once every 395 years. Call it a partner for
life, or at least for the next 5000 years, the period for which astronomers can reliably predict its chaotic orbit (which, relative to earth, is
depicted in green loops).
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Brains Grow at Earth's Poles
Underneath those horned helmets, Vikings may have sported big brains. Like other residents of the dark north, however, the Scandinavian pillagers
would've needed the grandiose noggins to see, not to sack cities. Scientists have long known that polar days tend to be shorter and dimmer, on average,
than their equatorial counterparts. Northern and southern peoples seem to compensate much like owls do, scientists report online today in the Proceedings of the Royal Society B. The researchers examined 55 skulls dating back to the 1800s and taken from various parts of the world.
They discovered that
humans living along the tropics tend to have smaller eye sockets than people dwelling at higher and lower latitudes. Since bigger eyes absorb more light, large polar orbs could make up for the twilight conditions there. In fact, high- and low-latitude natives seem
to see just as well in low light as tropical people do in bright light, according to the study. Cerebral size seems to grow by a few milliliters with
increasing and decreasing latitude, probably because the brain's visual centers expand as peepers widen.
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A Buzz in the Dark
Even at night, some bees are still out there, watching you with their dark vision. Three genera of Central American bees—Megalopta, Megaloptidia, and Megommation—eschew the sunshine, colorful flora (and predatory birds), and prowl instead for the
few flowers that bloom in the moonlight. Researchers in Panama caught thousands of these bees, trapping them on a bedsheet hung over a bright lamp, and
collected their DNA. By comparing their genetic sequence to that of 15-million to 20-million-year-old bees encased in amber found in the Dominican
Republic, they tracked how a gene for a protein in the eye called an opsin, which detects different wavelengths of light, has changed over the
millennia.
Just a few small spelling differences in the genetic code for that opsin made it better at detecting contrast than color, allowing these bees to morph from sunlit flower-flitters to buzz-by-night foragers 22 million years ago, the researchers report today in the Proceedings of the Royal Society B. But one genus of bees, a modern relative of Megalopta called Xenochlora, came back to the
light 7.6 million years ago; maybe it was afraid of the dark.
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Like Daughter, Like Mother
Moms, your daughters don't want to be like you when they grow up—or at least, they don't want to dress like you. It's the other way around, according
to a forthcoming study in the Journal of Consumer Behaviour. Researchers polled 343 mother-daughter pairs (average ages 44 and 16, respectively)
and found that mothers intentionally mimic their daughters' style—an effect the authors call the "consumer's doppelganger effect." Subjects were asked
about their perceived age, fashion consciousness, expertise in clothing and cosmetics, and the extent to which their mothers or daughters influenced
their fashion tastes. If a mother thought her daughter was a style expert and perceived herself as youthful, she had a 25% chance, on average, of
copying her daughter's clothes and cosmetics. Daughters, on the other hand, even if they felt older than their actual age and thought that their
mothers were stylish, only had a 9% chance, on average, of mimicking them. While it has long been known that children influence their parents'
consumptive behavior when it comes to products the family consumes as a whole, such as cars or food, this is the first study to show that children can
influence their parents' purchase of goods they consume for themselves, suggesting that children's influence on their parents is much more profound
than previously thought.
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Coral Genome Reveals Tiny Helper
The first full sequencing of a coral genome has revealed that corals originated much earlier than previously thought, and at least one important species is far more fragile than environmentalists had feared. Today, scientists from Japan's Okinawa Institute of Science and Technology announced that they've sequenced the genome of Acropora digitifera, a spindly reef-building coral that populates much of the Indo-Pacific oceans. Researchers identified 23,688 protein-coding genes. Comparing the coral's genome with its cnidarian relatives—jellyfish, sea anemones, and hydras—they found that corals emerged some 500 million years ago, which is 250 million years earlier than their earliest known fossil records. The researchers also discovered that A. digitifera lacks the enzymes necessary to produce an essential amino acid, cysteine. That means the coral likely relies on microscopic symbiotic organisms called dinoflagellates to biosynthesize cysteine for it, making the coral particularly susceptible to changing climate conditions that endanger its tiny helpers.
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The Milky Way's Dimmest Star Cluster
Bright stars may dazzle us, but it's the faint ones that test an astronomer's skill. After all, they're the hardest to detect, making their discovery a greater achievement. Now researchers report that a newfound star cluster in the constellation Pegasus is the dimmest ever seen. Whereas the Milky Way's greatest star clusters radiate millions of times more light than the sun, Segue 3, shown here in an image spanning 64 light-years, ekes out a mere 90 suns' worth of light. As astronomers will report in a future issue of The Astronomical Journal, the dim cluster is ancient, having formed 12 billion years ago. Located 55,000 light-years from Earth and 22,000 light-years below our galaxy's plane, Segue 3 resides in the Milky Way's halo, the population of old stars that surrounds the spiral-sculpted disk housing the sun. The cluster has cast most of its original stars into the halo and is destined to disintegrate completely.
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Tall People More Likely to Develop Cancer
Most people would probably rather be tall than short. But there's a downside to height: tall people are more likely to develop cancer. A
study published online today in The Lancet Oncology finds that this relationship holds in women with many types of cancer and across socioeconomic levels. The researchers looked at the incidence of 17 cancer types, from breast cancer to leukemia, over 9 years among 1.3 million women
participating in a long-term U.K. health study. Cancer risk rose 16% with every added 10 centimeters in height. The risk was similar when these data
were pooled with ten previous studies of cancer and height in men and women in Europe, Asia, Australia, and North America. The adult height of European
populations has risen 1 centimeter per decade since 1900, and this could have increased cancer incidence 10% to 15%, the researchers say. Why being
taller makes people more vulnerable to cancer is not known, however. One possibility is that the hormones that cause children to grow taller also
stimulate the growth of cancer cells.
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Rock, Paper, Scissors Not So Random
Every kid has his or her own strategy for prevailing in rock, paper, scissors. But despite their best efforts,
contenders for the crown may unconsciously mimic their sibling or chum's hand movements, forcing draw after draw, researchers report online today in Proceeding of the Royal Society B. The team organized roshambo matches in which
either one or both of the competitors wore blindfolds. Draws, such as rock versus rock, became a lot more common when one of the participants could
see. These players seemed to be unconsciously mimicking their rivals' subtle hand gestures like uncurling the index finger to make the shape of a
scissors. Scientists have seen similar imitation—people often tap their feet along to a beat when someone else is—before but couldn't tell if it
was voluntary or not. In this case, the aping must be involuntary, researchers say, since players wanted to win, not tie. Of course, as any bickering
siblings could attest, heat-seeking missile beats everything.
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Sex and the Single Insect
The female scale insect (Icerya purchasi) is an independent woman. She carries her own sperm—harbored in tissue passed down through the generations—so she doesn't need a male to have her babies. Scientists have long believed that this unique procreation strategy—scale insects are the only hermaphroditic insects and the only animal in the world to employ such a sperm packet—is harmful to the female, as the "sperm packet" consumes resources in her body that she could otherwise devote to making more eggs. But a new analysis, to be published next month in The American Naturalist, suggests that there are advantages to being single. By using her own sperm instead of mating with a male, the female keeps all of her family's genes in her bloodline. The strategy, however, may not be so good for the few males left in scale insect populations: They're becoming obsolete and may eventually go extinct.
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'Lost' Frog Found on Borneo
For 87 long years the Bornean rainbow toad was known to science from only a few sightings and a black-and-white illustration dating to the early 20th century. Then at the end of last year, researchers found three of the brightly colored amphibians high in trees along the rugged ridges separating Malaysian and Indonesian Borneo. Also called the Sambas Stream Toad or Ansonia latidisca, the species is listed as endangered on the International Union for Conservation of Nature Red List, and it may warrant protection under local conservation laws. The area in which the individuals were found is not currently protected. The discovery was announced by Conservation International (CI), which had included the toad on its list of the world's top 10 most wanted lost frogs. Last August, CI launched a global search for lost amphibians to find these and other frogs not seen for a decade or more. The Bornean rainbow toad joins the Rio Pescado stubfoot toad (Atelopus balios) of Ecuador as the only two "Top 10 Most Wanted" frogs to be found.
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Anemones Have Personality
For gelatinous blobs, sea anemones have a lot of personality. Animals are considered to have personalities when individuals show consistent differences in behavior across time or situations. In a paper published online this month in PLoS ONE, researchers showed that over the course of 3 weeks, individual wild beadlet anemones, Actinia equina, were remarkably reliable in how long they kept their tentacles withdrawn after being surprised by squirts of water. Each anemone maintained its "startle response" for anywhere from about 3 to 20 minutes, but the duration was roughly the same in response to every squirt. And the trend held regardless of the temperature in the anemones' tide pool homes, a variable that can affect behavior. In fact, the anemones showed more consistency than most other animals tested for personality in the wild. A variety of vertebrates and a handful of invertebrates, including octopuses and spiders—even a bacterium—are members of the personality club, but the researchers say sea anemones set a new bar as the animal with the simplest nervous system.
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It's Lonely—And Stressful—At the Top
For savanna baboons (Papio cynocephalus), ruling a banana republic comes at a price. A new analysis of fecal samples reveals that these
alpha males have higher levels of stress hormones than their immediate underlings and similar levels to low-ranked monkey serfs. The findings, reported online today in Science, challenge the prevailing thinking among primate
scientists, who believe that—outside of times of social upheaval, during which cocky upstarts dispose more dominant males—alphas should live in
stress-free bliss. But savanna baboons may not have the time to sip cocktails. In these societies, the rank-and-file frequently topple their leaders,
so the top dogs scuffle much more than subordinates to hold onto power. Such constant stress can hamper the immune response and monkey health,
potentially holding these kings back from siring as many offspring as they should.
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Asteroid Vesta Emerges
With NASA's release today of the latest image from the approaching Dawn spacecraft, asteroid Vesta is no longer a fuzzy, nearly featureless ball; it's a surprisingly youthful world, geologically speaking, sporting still-mysterious features. Although Dawn will go into close orbit around 529-kilometer-diameter Vesta this weekend, the newly-released image of the asteroid—taken 9 July from a distance of 41,000 kilometers—already reveals never-before-seen detail that has planetary scientists scratching their heads. Hubble Space Telescope had already revealed the peak or mound in the left-center; it marks the heart of an enormous impact crater spanning 460 kilometers (apparently hard to see from this perspective). But there are also roughly parallel ridges, grooves, or who knows what that swirl across the lower part of the image. And then there is what's missing: innumerable smaller impact craters accumulated over the eons. Dawn's year-long visit could show whether the humongous impact obliterated them as it wiped Vesta's geological slate clean.
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Tropical Lizards Get Brainy
Tropical lizards may have tiny brains, but they're quick learners. In a new study, researchers placed a block containing two wells, one covered by a
blue disk, in front of the tropical arboreal lizard Anolis evermanni. The reptiles quickly learned that the blue disk covered a tasty fly larva,
and even when the team tried to confuse them by placing a yellow disk or a blue disk with a yellow perimeter on the second, empty well, only one lizard
out of four made a mistake over six trials. The lizards also needed at least three fewer practice runs to learn the task than did song sparrows and
other bird species performing comparable tasks in other studies, the researchers report online today in Biology Letters. What's more, the
lizards developed two strategies to dislodge the disk: They either bit the edge or used their snouts as levers. The team says this problem-solving
behavior was completely unexpected because lizards have never before been observed using these strategies in the wild. The findings suggest that the lizards may be as smart as birds and some mammals—at least
when it comes to snatching a snack.
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Female Crickets Hear Everything
Birds and monkeys aren't the only animals that have unique mating calls; crickets also croon when seeking a partner. But in the tiny tree cricket (Oecanthus henryi), males change their rhythm and pitch—from slow and low to fast and high—as the
temperature rises. So how does Ms. Tree Cricket find a hubby on a hot day? Using a beam of laser light, researchers looked into female crickets' ears
to see their response to a range of frequency levels and tones. Using vibration-analyzing software, the team found that, instead of attuning their ears
to track a male's chirrups, which range from 2.5 to 4.5 kHz, the females were listening to everything from 0.5 to 20 kHz. That helps them keep track of
potential mates, no matter how high the mercury rises.
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Scientists Sequence the Spud
Potatoes are the most important nongrain food crop in the world—and scientists are finally starting to learn a bit more about them. Researchers
report online today in Nature that they've completed the first high-quality genome sequencing of the potato, revealing key regions that could
help growers breed varieties with better resistance to disease and insect infestations, as well as potentially increase crop yields and potatoes'
nutritional value. The potato has about 39,000 protein-coding genes, the team found, slightly less than the soybean and a bit more than corn. The
researchers also discovered that the clade asterid—which potatoes belong to along with tomatoes, coffee, and tobacco—likely split off from
rosids (grapes, poplar trees, geraniums, etc.) around 89 million years ago. Now pass the sour cream.
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'Beehive Fences' Keep Elephants Out
African elephants are afraid of bees (they even have an alarm call for them), and scientists are now
using that fear to help protect the crops of Kenyan farmers. In previous studies, a team of researchers showed that the behemoths rapidly leave areas where they hear the sound of buzzing bees. Now these
same scientists have designed and tested a fence that incorporates beehives spaced 10 meters apart. The team installed 1700 meters of the fences along
the boundaries of 17 farms in Northern Kenya that are often raided by wild elephants; another 1700 meters of the same farms were protected only by
thorn tree fences. After two years, the beehive fences easily won the contest: only one bull elephant broke through this fence, while 31 elephants
managed to crash the thorn fence, the scientists report in the current issue of The African Journal of Ecology. Beehive fences can thus be used to help limit the number of human-elephant conflicts, a
growing problem as the human population in Africa increases, and farmers and elephants compete for land and water resources, the researchers say.
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Billion-Pixel Array Will Map the Milky Way
Technicians have assembled the largest digital camera ever built for a space mission. Completed last month, the so-called billion-pixel array (shown during assembly) is made up of 106 charge-coupled imaging devices, each slightly smaller than a credit card and thinner than a human hair. Part of the European Space Agency's Gaia probe, the camera is due to ride into space in 2013, the agency reported yesterday. During the 5-year mission, Gaia's instruments will repeatedly measure the position, color, intensity, and spectra of stars and other objects as dim as magnitude 20, about 400,000 times fainter than can be seen with the naked eye. The resulting 3D star map will include more than 1 billion stars in our galaxy and in nearby star clusters and should provide unprecedented insights into the composition, formation, and evolution of the Milky Way. Besides discovering thousands of distant, dim objects such as brown dwarfs, Gaia's sensors will likely detect hundreds of thousands of comets, asteroids, and other minor bodies in our solar system, the researchers say.
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A Planet-Wide Thunderstorm
A small, bright feature that suddenly appeared in Saturn's northern hemisphere late last year and grew to a diameter approaching Earth's in a matter of
weeks is a thunderstorm that's still raging. The day it was first observed in early December, the cloud measured only 2500 kilometers across, about the
distance from Boston to Dallas. Three weeks later (shown on 24 December 2010), the storm system measured 17,000 km across and sported a tail that
eventually stretched around the planet. Instruments on board the Cassini probe detected bursts of radio waves generated by lightning flashes that, at
their peak, occurred at least 10 times per second, an international team of researchers reports today in Nature. Thermal energy brought up from lower layers
of the atmosphere and released by the storm rivals that emitted by the entire planet in quiet times, the scientists note. Such storms, called "Great
White Spots" due to their size and brightness, can be seen by Earthbound astronomers and occur on average every 30 years or so—approximately the
length of a year on Saturn—but for some unknown reason this year's storm has appeared much earlier in the Saturnian spring than normal.
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The Rise of Jaws
A new analysis of the first fish with the ability to bite is giving paleontologists plenty to chew on. Gnathostomes—vertebrates with jaws, including
shark predecessors, the forebears of bony fish (including our own ancestors), and now-extinct lineages such as the armor-plated placoderms—originated between 444 million and 416 million years ago. As reported today in Nature, however, their rise to dominance was more complicated
than previously thought. Paleontologists had hypothesized that the evolution of different jaw types, from slicers to crushers, allowed the gnathostomes
to rapidly replace jawless fish. But, according to the new study, jawless fish coexisted with gnathostomes for millions of years. It was only after 400
million years ago, when all the major jaw types had been established, that gnathostomes began to take over. Biting may have given the gnathostomes an
evolutionary edge, but, like their blood-sucking relative the lamprey, jawless fish hung on for a long time.
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Why Fish Haul Around Extra Guts
Put a fish in a tank with unlimited food and it will gobble until it grows many times its size. This is possible because the fish has a much larger
digestive system than it actually needs. But why spend so much energy maintaining all of these guts when fish in the wild don't eat nearly as much? A
new analysis of 600 fish populations (including the bluegill, pictured), reported online today in Nature, suggests that
large guts help fish deal with feast or famine conditions in the wild. A digestive system that's two or three times bigger than needed helps these fish gorge on food when they find it and store the calories for times
when food is scarce. And, in the long run, that makes hauling around a bunch of guts worthwhile.
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How Tree Frogs Keep Their Feet Sticky
Trying to re-stick a piece of tape to a surface after it's become dusty is infuriating. So how do tree frogs pull it off? It turns out the arboreal
amphibians, which secrete gluey mucus from pads on their feet, refresh their stickiness with every step they take. Biologists presenting at the Society
for Experimental Biology annual conference in Glasgow found that the White's tree frog (Litoria caerulea) self-cleans as it climbs thanks to
special channels in its feet that slime away dirt and debris. When the frog moves its limbs forward, the mucus and any accumulated gunk slip through
the channels and stay behind while new sticky mucus is secreted in its place. The researchers say these findings could one day inspire such technology
as self-cleaning medical bandages and self-renewing adhesives.
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Old Spiders Weave Messy Webs
In humans, we associate getting older with cobwebs of the mind; in spiders, it's the cobwebs themselves that suffer. On Saturday, biologists will
present research at the Society for Experimental Biology annual conference in Glasgow showing that as spiders age, they build shabbier, less perfect
webs than they did in their youth. As a young creepy-crawly, the European house spider, Zygiella x-notata, weaves intricately patterned webs
with regular spacing and exact angles, like this one in the left photo, built by a 17-day-old spider. The web in the right photo was built by a 188-days-old spider nearing the end of its
life, and its web design is far more irregular and shows numerous gaps. Researchers suspect that, like in humans, the spider's central nervous system
breaks down in old age. If that's the case, studying how these spiders' weaving skills deteriorate with age could help scientists learn more about
aging's effect on human behavior, too.
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Tiny Bug Makes a Riot With Its Privates
The world's loudest animal relative to its size has been revealed to be a tiny bug with a big organ. Specifically, the water boatman, Micronecta scholtzi, rattles its penis along grooves in its abdomen to produce a chattering song—that registers at 99.2 decibels—about the volume of a loud orchestra heard from the front row. Scientists presenting at the Society for Experimental Biology annual conference in Glasgow recorded the bug and analyzed its volume compared to various other loud animals. Even though the water boatman does its "singing" from the bottom of rivers to attract mates, humans walking along the riverbank can clearly hear it. The area along its abdomen that the bug uses to make the noise is only about the width of a human hair, and researchers aren't sure exactly how it produces so loud a song.
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A Beetle With Screws for Legs
Nature is full of marvels of engineering that humans have co-opted for their own mechanical feats. Ball and socket joints let your arm bones rotate at
the shoulders and also allow the wheels of your car to be turned through the steering column. But it isn't often that a device engineered by humans is
later found to also exist in nature. Researchers now report just such a discovery: the joint of a beetle leg that turns inward and outward like a screw. The legs
of the beetle, which belong to a species known as the Papuan weevil, have circular threads covering 410 degrees—more than one full rotation around
the leg (right). The inside of the joint has corresponding threads (left). Muscles control how much the leg can turn on the screw threads, the
researchers report online today in Science. They suggest that the unique features of the joint, which they've now pinpointed in multiple species
of weevil, give the beetle extra flexibility when feeding on twigs and foliage, and extra stability when it's in a resting position. It's much harder,
they say, to dislocate a screw than a round-ball-and-socket joint.
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Why Wallabies Don't Pass Methane Gas
When cows digest food, they produce methane, a potent greenhouse gas, but when kangaroos chow down, their digestive tract is relatively methane-free.
The difference comes down to one group of bacteria, new research suggests. Scientists studying wallabies, a smaller relative of kangaroos, isolated gut
bacteria that they have now classified as Wallaby Group 1 (WG-1). When the researchers grew the bacteria in a nutrient broth, they found that
the microbes produce a compound called succinate instead of methane as an end product of digestion. As succinate is not a greenhouse gas, the scientists hope that further studies on the WG-1 bacteria will help researchers find a way to modify
livestock to produce less gas—methane gas, that is.
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Distant Quasar Is Early Universe's Brightest Object
The light from this cosmic beacon took 12.9 billion years to reach Earth, but the sight was worth the wait. Astronomers say it is the most distant
quasar, a massive black hole surrounded by luminous gas, that they have ever seen as well as the brightest object to be sighted in the early universe.
Its distance means
astronomers are seeing it blazing away at a time when the universe was merely 770 million years old, a team reports online today in Nature. The quasar's brilliance is powered by a monstrous black hole at its center that's 2 billion times more
massive than the sun. The energy radiating from it would have contributed to the last phase of reionization of the early universe, the
process that helped clear away the hydrogen fog shrouding the infant cosmos. More distant objects have been spotted in recent years, such as a gamma ray burst and a galaxy more than 13 billion light-years away, but this
quasar is hundreds of times more luminous.
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Happy Orangutans Live Longer
Happy humans tend to live longer, and the same appears to hold true for orangutans. In a new study, published online today in Biology Letters,
researchers surveyed the well-being of 184 zoo-housed orangutans by asking zookeepers to answer a four-item questionnaire. Keepers were asked to rate
the orangutans' general positive mood, social life, and ability to reach desired locations and objects.
Those orangutans judged to be the happiest were 42% less likely to pass away within 7 years after the survey was taken. The researchers suspect that, just like humans, happier apes tend to have less stress and health problems, which helps them to live longer.
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Right Whales, Finally Coming Home
After more than 100 years, right whales have returned to their calving grounds in New Zealand, scientists report. The 100-ton whales, known for their
social frolicking and impressive acrobatic displays, were hunted to extinction in these same waters during the 19th and 20th centuries' era of
industrial whaling. A small population managed to survive near remote, sub-Antarctic islands south of New Zealand. In recent years, a few dozen females
found their way back to the same bays their ancestors used for bearing their young. Normally, such cultural knowledge is passed from
mother-to-daughter, the researchers say. But the tradition had been lost, until these pioneering females began making the journeys once again.
Reporting today in Marine Ecology Progress Series, the scientists confirmed that some of the females had migrated from the southern islands to New Zealand by
comparing the DNA in tissue samples collected from seven whales at both sites. Now that the tradition has been restored, scientists expect more whales
to follow the pioneers.
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Contrails Warm the Globe
The white, cloudy contrails airplanes often leave in the sky may be full of ice crystals, but they're warming the globe, according to a new study. By
flying in the wake of various aircraft—ranging in size from the 47-metric-ton Airbus A319 to the 508-metric-ton Airbus A380 (contrails of two Airbus
A340s shown)—and analyzing their less-than-10-minute-old contrails, researchers have found that fresh contrails tend to trap outbound infrared
radiation, slightly heating Earth. Based on 2005 air traffic figures such contrails, if their effect were to be evenly spread out across the globe,
would continuously trap 15.9 milliwatts of power per square meter, the researchers report this month in Geophysical Research Letters. That's
about 1% of the amount trapped by the carbon dioxide added to the atmosphere since the beginning of the Industrial Revolution.
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Dawn Closing In on Asteroid Vesta
On 16 July, NASA's Dawn spacecraft will
for the first time go into orbit around one of the asteroid belt's big "protoplanets," a rocky body so large that eons ago it began to evolve
geologically along the same path taken by Earth. At a press conference today, Dawn team members showed their latest image of the 529-kilometer-diameter
asteroid Vesta (left), which has more than twice the detail that the Hubble Space Telescope was ever able to muster from Earth orbit (right). From
154,000 kilometers—one-third the distance from Earth to the moon—scientists still can't say much about what they are looking at. Many of the
fuzzy features must be impact craters formed in collisions with smaller asteroids over more than 4 billion years. The largest impact, near the south
pole, is thought to have blown off bits and pieces of Vesta that ended up falling on Earth as meteorites. Instruments onboard Dawn should be able to
confirm the meteorite-Vesta link and let Dawn researchers better understand another body that melted and separated into crust, mantle, and metallic
core. After a year in Vesta's orbit, Dawn will spiral away on its ion engines to another, icier protoplanet, Ceres.
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ScienceShot: A Smashing Beauty
On Earth, collisions rarely lead to beauty. In space, it's a different story. Astronomers in Japan say one of the best-known nebulae—the Trifid, in
the constellation Sagittarius—owes its splendor to a smashup between two clouds of gas and dust. Lying
roughly 7000 light-years from Earth, the Trifid Nebula consists of a red region where three dark dust lanes resemble a peace sign; an adjoining region
is blue. By using telescopes in Chile, the astronomers measured Doppler shifts and thus velocities of gas in the Trifid. As the researchers will report
in a future issue of The Astrophysical Journal, two gas clouds likely collided in the Trifid's red region 1 million years ago, compressing gas
that collapsed to spawn new stars. One newborn star, named HD 164492, is so hot that its radiation tears electrons from protons. When the two rejoin,
the electrons emit the red glow seen here. Future fireworks are forthcoming, for the star will someday explode as a supernova.
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Young Monkeys Don't Pardon the Interruption
As human children learn to talk, they begin to pick up on the rule that interrupting is not allowed—although it may take some parental nagging for the
rule to sink in. Monkeys are no different, new research shows. The core of communication in Campbell's monkeys (Cercopithecus campbelli), which
are native to western Africa, revolves around alternating vocal calls. Researchers recorded spontaneous utterances of both young and adult monkeys and
tallied how often each broke the rules of alternating calls. The adults broke the rules--calling twice in a row instead of letting another monkey take
its turn—less than 1% of the time. The juveniles, however, were rule-breakers in 13% of their calls. Moreover, when played calls that either followed
conversational rules or didn't,
adults gave more attention to conversations with a clear alternating pattern, whereas juveniles didn't seem to differentiate. The findings, which appear today in Scientific Reports, could help scientists learn more about how language evolved in humans—just as long no
one cuts anyone else off.
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Darwin's Library, Just a Click Away
When Charles Darwin was done reading Charles Lyell's Principles of Geology, he scribbled on the last page, "if this were true[,] adios theory." Such comments appear in the margins of about half of the famed naturalist's 1480 books, revealing an avid, thoughtful reader constantly evaluating his ideas and those of other authors. Now anyone can peer into those pages to see how Darwin's thinking was evolving as he developed his theory of evolution. The 330 most heavily annotated titles—419 volumes in all from his personal library—are now digitized and online at the Biodiversity Heritage Library, a project to put natural history information on the Web. The image of each page comes with a window describing the locations of Darwin's notes and a transcription of his somewhat illegible scrawl. One can also search his scribblings by subject.
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'Cluster Flocking' Is No Energy Saver
When birds take to the air in a large group, they typically either fly in a V-formation or in a swarmlike cluster. Both have their benefits: the
V-shape is aerodynamically efficient, saving geese and other birds energy during flight, while cluster flocking can help birds like pigeons guard
against predators. But the cluster has one big disadvantage, according to a study published online today in Nature. When researchers followed 18
pigeons with GPS, they found that the birds gained neither an aerodynamic advantage nor added energy efficiency when flying in a cluster. In fact, the
team believes that it takes pigeons more energy to fly in a flock than to fly solo. So why do they do it? In addition to predator protection, the
researchers speculate that cluster flocking may help the birds navigate; a follow-the-crowd mentality.
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Life on Enceladus?
Spouting plumes of ice and water vapor certainly make Enceladus one of the solar system's liveliest places. But continuing studies of the composition
of those plumes are now making Saturn's icy moon the most promising place to look for extraterrestrial life. Researchers reported at a May meeting and online
today in Nature that the best sampling yet of the plumes by the Cassini spacecraft reveals strong evidence for liquid water beneath the deeply
frigid surface—an ocean, a sea, or at least water-filled cracks. Solid ice had been a contender to explain the gases and particles found in the
plumes. But Cassini observations, including ever-rising estimates of the amount of heat given off by the moon, were challenging the ice-only source.
Now analyses of Cassini data from a flyby through the heart of the plumes show that 99% of the mass of plume ice-particles is salt-rich. That alone
strongly implies that the water in plume ice came from salty liquid water somewhere beneath the surface, say the researchers. Direct proof of a watery
interior must likely await another mission, which may not come for decades.
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Ladybugs as Bodyguards
This ladybug may look like she's protecting her brood. But the cocoon perched between her legs is actually a parasite taking advantage of a safe space
to grow. The parasitic wasp Dinocampus coccinellae is known to lay its eggs in the circulatory system of ladybugs, where larvae feed on ladybug
tissues before pushing out of her abdomen. Then, the developing parasite spins a cocoon between the ladybug's legs. A new study, appearing online today in the Journal of the Royal Society Biology Letters, explains why the parasite doesn't kill the ladybug during this whole process. When scientists
setup an artificial ecosystem in the lab, complete with ladybugs, parasites, and lacewings, insects that like to make a meal of wasp cocoons, they
found that when the cocoons were between the legs of a living ladybug, only 35% were killed by predators, compared with 85% if the cocoon was attached
to a dead ladybug, and nearly 100% if it was free from any ladybug. So the ladybug above may not be protecting her offspring—but she is protecting
herself.
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ScienceShot: Mercury Reveals Some Surprises
The solar system’s innermost planet may look like a dead ringer for Earth’s moon, but the scientists getting the closest look ever at Mercury want you to know one thing: Mercury is not the moon. And it isn’t anything like the other rocky planets—Earth, Mars, or Venus—either. At a NASA press conference today, researchers reporting on the first three months that the MESSENGER spacecraft has been orbiting the sun’s closest neighbor emphasized many distinctive mercurian aspects. Perhaps the most fundamental is an abundance of elements that can be easily boiled out of hot rock. Team members have been gauging rock composition by measuring the x-rays and gamma-rays emitted by a surface bombarded by the sun’s x-rays and by cosmic rays. The latest analyses show ten times more sulfur than found in Earth’s or the moon’s surface rocks and as much or more potassium. That rules out some previously proposed ways of forming Mercury with its relatively huge molten iron core, such as having the nascent sun blasting away the outer rind of an Earthlike planet. Still in the running is a huge impact that blew away an outer layer of Mercury. With all systems go, MESSENGER has 9 months left in its planned mission.
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Powerful Jet Being Produced by Star-Eating Black Hole
On 28 March, NASA’s Swift satellite
observed a flash of gamma rays brighter than anything astronomers had seen before. It soon became evident that the event wasn’t a typical gamma ray burst, an emission of high-energy radiation that often accompanies a supernova
explosion. The flash didn’t die out but was sustained for weeks, and although it has faded in intensity, it is still going strong 2½ months later. Two
papers published online today in Science provide an explanation for this luminous surprise. The flare is in fact a high-energy jet of radiation produced by a star falling into a black
hole at the center of a galaxy 4 billion light-years away. The reason the flare is so bright is that the jet is pointed straight in the direction of
Earth. And it’s sustained because the black hole is consuming the star gradually. “That’s because as the
black hole rips the star apart, the mass swirls around like water going down a drain, and this swirling process releases a lot of energy,” says Joshua
Bloom, an astronomer at the University of California, Berkeley, and lead author of one of the two papers. Bloom expects the flare to fade out over the
next year.
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Police Dogs Can Distinguish Identical Twins
Being an identical twin might seem like a great way to fool a DNA test and get away with the perfect crime. But furry forensic experts can make sure
justice is served. In a new study, researchers instructed a group of children, including two sets of identical twins and two sets of fraternal twins,
to swab the insides of their cheeks and place the swabs in glass jars. Working with ten police German shepherds and their handlers from the Czech
Republic police, the researchers then ran a mock crime scene investigation. The handler presented one twin’s scent to the dog and then told it to go
find the matching scent in a lineup of seven jars, which included the other twin’s scent.
In twelve trials per dog, none of them ever identified the wrong twin as a match, the researchers report online this week in PLoS ONE, even though the children lived in the same home, ate the same food, and had identical
DNA. No word yet on whether these dogs will be getting their own CSI spinoff.
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Crocodile-Snouted Dinosaur Discovered Down Under
More than 100 million years ago, Australia was home to a unique blend of predatory dinosaurs. The latest to be added to the mix—thanks to a single
neck vertebra (pictured above) that was found in Victoria and described today in Biology Letters—is a bizarre class of crocodile-snouted
carnivores called spinosaurs. These peculiar dinosaurs have previously been found in South America, Europe, Africa, and Asia, and the Australian fossil
closely resembles a spinosaur known as Baryonyx from England. Combined with other fragmentary skeletons attributed to tyrannosaurs, raptors, and
allosaurs, this as-yet-unnamed spinosaur may help
paleontologists figure out when different dinosaur lineages arrived in Australia and, consequently, when and how the continent split from other land
masses 80 million years ago. Prior to that time, all the southern continents were merged in a supercontinent known as Gondwana, and the new find—combined with other dino discoveries that indicate that Australian dinosaurs more closely resemble their counterparts in South America rather than
Africa—suggests that Africa may have been the first to split off.
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Volcano CO2 Emissions No Match for Human Activity
A popular myth among climate change skeptics is that volcanic emissions of carbon dioxide dwarf those generated by humans. But a new report in today's
issue of Eos reveals precisely the opposite:
In a mere 2 to 5 days, smokestacks, tailpipes, and other human sources of CO2 spew a year's worth of volcanic emissions of that
greenhouse gas. According to the paper, five recent studies suggest that volcanoes worldwide (such as Alaska's Shishaldin, shown) emit, on average, between 130
million and 440 million metric tons of CO2 each year. But in 2010, anthropogenic emissions of the planet-warming gas were estimated to be a
whopping 35 billion metric tons. Individual events—such as Mount Pinatubo, whose major eruption in 1991 lasted about 9 hours—can produce CO 2 at the same rate that humans do, but they do so only for short periods of time. It would take more than 700 Mount Pinatubo-sized eruptions
over the course of a year to emit as much carbon dioxide as people do, the study notes.
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'Alzheimer's' in the Down Syndrome Brain
By the time they're older, most Down syndrome patients develop a distinct form of dementia that mimics Alzheimer's disease. And sure enough, autopsies
of Down syndrome patients have found proteins in their brains that build up between nerve cells, called amyloid plaques, and twisted fibers inside
neurons, called tau tangles. Both are known physical manifestations of Alzheimer's that keep neurons in the brain from functioning properly. When
researchers compared levels of plaques and tangles in healthy brains (center) with the brains of young and middle-aged, dementia-free Down syndrome
patients (left) and with the brains of Alzheimer's patients (right), they found similarly high levels of plaques and tangles in the Alzheimer's and
Down syndrome patients. But unlike in Alzheimer's,
the highest levels of amyloid and tau in Down syndrome brains were in the parietal and frontal regions of the brain, the team reports in the July issue of Archives of Neurology. These areas are associated not only with memory, but with behavior and reasoning.
This could explain the change in a patient's personality that happens earlier in Down-related dementia than in Alzheimer's, the team says, offering
researchers a new way to track dementia in those patients.
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A Tornado's Path of Destruction
The lengthy swath of destruction that a tornado plowed across Massachusetts earlier this month stands out starkly on satellite images. On 10 June, NASA
released images from a Landsat satellite taken before (top) and after (bottom) the 1 June tornado carved a 63-kilometer (39-mile) path from
Springfield to Sturbridge. In the image taken on 8 October, only cities, roads, and other signs of human development can be discerned. In the view
taken 5 June, however, part of the light-colored corridor of twister damage, which at its widest measured about 800 meters across, can easily be
recognized—largely because the peak winds of the EF3 tornado, which probably measured between 219 and 266 kilometers per hour, stripped trees bare of
vegetation, increasing the contrast between the damaged landscape and the intact trees nearby. A full satellite view of the tornado damage hasn't been
generated, because during the only Landsat pass over the area since the event the westernmost portion of the tornado's path was blocked by clouds
(white blotch at upper left of bottom image).
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What Makes a Finch Unfaithful?
Some birds chirp to show happiness, but when a male zebra finch sings to a female finch he's never met before, he's looking to have an affair. If she
sings back, she's probably willing to have one, too. But affairs make more sense for males than for females; when males mate outside of their typical
monogamous coupling, they spread their genes far and wide, but adulterous females don't spread their genes any further than they would otherwise and
additional fathers do not help raise offspring. So why do females do it? A new analysis of courtships from thousands of encounters between finches, as
well as genetic analyses of paternity, reveals that the
female offspring of more promiscuous males are more likely to mate with multiple males themselves. The reason, researchers report online today in the Proceedings of the National Academy of Sciences, may be that some males harbor a
"promiscuity gene" that they pass down to their offspring, both male and female.
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An Infectious Personality
Can a parasitic infection change your personality? It can if you're a mallard duckling. These birds typically avoid unfamiliar objects and prefer items
that are green and blue. But when researchers injected Anas platyrhynchos ducklings at 4, 9, or 14 weeks old with red blood cells from sheep to
simulate a parasitic infection, the birds—as adults—explored new items in their environment and approached small orange toys, a color they
typically avoid because they seem to associate it with toxic food. Reporting online today in the Proceedings of the Royal Society B, the
researchers hypothesize that these so-called personality changes may help adults explore a larger area and find more food. And this in turn may help
them make up for the energy they've lost fighting the infection.
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How Jellyfish Poop Fouls Up the Food Chain
April showers bring May flowers, but April pollution brings May jellyfish "blooms." The sudden, seasonal appearance of thousands of the creatures occurs in waters warmed by climate change and in areas where overfishing has removed the food competition for invasive jellies. To study how these blooms affect ocean food chains, researchers examined two species of jellyfish that bloom in the Chesapeake Bay every summer. When these jellyfish dine on zooplankton and other carbon-fixing organisms, they convert the food into a gelatinous, carbon-rich excretion. A few, normally rare species of bacteria quickly eat this waste and convert its carbon into CO2, the researchers report online in the Proceedings of the National Academy of Sciences today. This removes the carbon from the waters, preventing fish and other organisms from using it as a food source, ultimately starving out some sea life.
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Mount Rainier Has Lost One-Seventh of Its Ice and Snow
About 14% of the ice and permanent snow atop Washington's Mount Rainier melted in the last 4 decades, a new study suggests. Researchers arrived at that
figure by comparing the estimated thicknesses and extents of ice seen in a 1970 aerial survey with those measured by an airborne laser altimeter in
2007 and 2008. All but two of the 28 glaciers and snowfields have thinned and shortened at their lower edges, and the exceptions likely thickened only
because large amounts of rock fell upon the ice in recent years and insulated it from warming temperatures. Overall, the volcanic peak lost about 0.65 cubic kilometers of ice—enough to cover the entire state of Rhode Island to a depth of 20 centimeters—during the 38-year interval between surveys, the researchers report
online inGeology. Prior to the ongoing meltback, Mount Rainier's ice and snow coverage expanded from the late 1950s to around 1980 during a
wetter-than-normal phase of a multi-decadal climate cycle called the Pacific Decadal Oscillation. These recent trends indicate that Mount Rainier's
glaciers are very sensitive to warming and could grow again with modest changes in temperature or precipitation, the scientists say.
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A Galactic Hit and Run
Bad things can happen to good galaxies. The blue object in this image is a rare ring galaxy, 440 million light-years from Earth in the constellation
Cetus. The ring was once a normal giant galaxy like our own, but a smaller galaxy smashed right through its disk. The intruder's gravity first pulled
stars and gas toward the victim's center. Then, after the smaller galaxy plunged through the disk and came out the other side, the stars and gas rebounded
outward, creating an expanding ring that squeezed gas into new stars, the brightest of which shine hot and blue. The ring now measures 38,000
light-years across, about a third the diameter of the Milky Way's disk of stars. Recently astronomers at the University of Oxford used the 200-inch
telescope atop Palomar Mountain in California to measure velocities in the ring. These measurements, to be reported in Monthly Notices of the Royal Astronomical Society, reveal that the intruder galaxy struck at an angle of about 45˚ from the perpendicular some
50 million years ago. The guilty party isn't hard to find: it's the odd-looking galaxy left of the ring. Together the pair is known as Arp 147.
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You Are Here
BOSTON—Astronomers have produced the most complete 3D map of the nearby universe to date. Using telescopes in both hemispheres, they measured distances to a
whopping 45,000 galaxies out to a distance of 380 million light-years—for the astronomy buffs, a red shift of .07. Unlike the famous Sloan Digital Sky
Survey, which mapped only part of the sky, the new 2MASS Redshift Survey covers 95% of surrounding space, skipping over only the region near the plane
of our own galaxy, where the Milky Way's stars and dust block the view of remote objects. In the map, color codes for distance: purple dots are nearby
galaxies; red dots are distant ones. Among other things, the new map will help astronomers to understand and explain the motion of the Milky Way, which
is apparently being tugged by the gravity of neighboring groups and clusters of galaxies, says 2MASS team member Karen Masters of the University of
Portsmouth in the United Kingdom, who presented the it here at the summer meeting of the American Astronomical Society.
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Why Seabirds Say Smell You Later
Soaring over a throng of males who immediately inflate their throats like red balloons to show off their virility, a female frigatebird lands next to
the one with the biggest and reddest throat and offers him her companionship. But the chicken-sized seabird may abruptly dump her potential mate if he
smells too similar to herself. By examining the genes of a Hawaiian population of frigatebirds, researchers found that females prefer to mate with
males who have a set of proteins called major histocompatability complex (MHC) markers that are genetically different from their own, regardless of
whether the two love birds are related. Fish and mammals appear to distinguish different MHC proteins by smell, so the birds may as well, the
researchers argue today in Proceedings of the Royal Society B. As MHC proteins are involved in immune response, a diverse array of them from both parents might help
offspring avoid a wider range of pathogens, the researchers speculate, which is more important than a big, pretty throat.
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X-raying a Supernova Factory
Each of the 14,370 pinpricks of light in this x-ray image is a hot, young star in the Carina Nebula—a giant cloud of gas and dust some 7500
light-years from Earth where new stars are being born. Obtained by NASA's orbiting Chandra X-ray Observatory, the new mosaic image was presented today
at the summer meeting of the American Astronomical Society in Boston. Chandra doubled the number of massive stars that are known in the nebula, which
is only a few million years old. Such stars end their brief lives in titanic supernova explosions, so supernovae in Carina must also be twice as
frequent as had been assumed until now—and the same might be true for other star-forming regions in our galaxy. Moreover, Chandra has found six
neutron stars—the hot, dense remains of supernova explosions—in the stellar nursery. So the celestial fireworks must have already begun, and the next
star could detonate tomorrow.
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Perfumed Nightclubs Rock
In nightclubs, body odors and the stench of stale beer stand out. Most nightclubs now forbid smoking which, for better or worse, used to cover up those smells. Can giving patrons whiffs of something more fragrant make them happy and coax them into buying more drinks? A private company called MoodScent in Amsterdam, whose mission is to "revolutionize the nightclub experience," thinks so. Along with a pair of university researchers, they pumped orange, seawater, and peppermint scents into a set of three clubs in Germany and Holland over different nights. They filmed the clubbers and rated them on their dancing, and had them fill out questionnaires as they left. Online in Chemosensory Perception this month, the authors report that visitors were more cheerful, danced harder, and were more confident in approaching the opposite sex when there was a scent—it didn't matter which one. The clubs' alcohol sales were higher, too.
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How a Lizard Lost Its Legs
"Worm lizards," a group of mostly legless reptiles, have long puzzled zoologists. Are these animals (right)—also known as amphisbaenians—lizards that
lost their legs over time, or are they closer relatives of snakes? Thanks to an approximately 45-million-year-old worm lizard fossil found in Messel,
Germany's exquisite fossil deposits, the mystery has now been solved: Amphisbaenians are truly lizards, after all. As reported online today in Nature, the nearly complete skeleton of the small fossil lizard Cryptolacerta hassiaca (left) had a thick skull characteristic of modern
worm lizards, yet the reptile retained arms and legs. Although this animal was about 20 million years too late to be a direct ancestor of other worm
lizards, the researchers propose that it retained the form of worm lizard ancestors and is therefore useful in tracking the group's origins. Not only
does the find indicate that these peculiar lizards independently paralleled snakes by losing their limbs, but that a sturdy skull adapted to burrowing
and rooting through the leaf litter preceded the loss of limbs in these lizards. Once the lizards began burrowing, their arms and legs gradually became
reduced in size and they eventually took on a superficially snakelike appearance.
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How the Snail Picked Its Poison
It's frustrating to be a predatory snail: everybody can outrun you. To make that annoying meal hold still, the cone snail, a giant marine mollusk,
evolved a mouthful of hollow harpoon teeth, which it loads with venom, lobs at prey to paralyze them, then retracts into its mouth. But the poison
gland itself, which is anatomically unique in its spaghetti shape, has mystified scientists for over a century. Revisiting a strange observation by a
19th century French naturalist who believed that the venom glands developed from tissue stripped away from the esophagus, a researcher cut up baby
snails and studied their throat anatomy. She found that a very small structural change in the esophagus, which would have been too small to disrupt an
ancestral snail's herbivorous habits, becomes a venom gland after the snail becomes an adult. Reporting online today in the Proceedings of the Royal Society B today, the researcher says that this smooth transition may explain how these snails developed their complex arsenal and became carnivorous over a short evolutionary
timeframe.
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Spiders' Silk Slippers Help Them Stick
By all laws of physics, spiders as big and heavy as tarantulas shouldn't be able to climb walls or hang upside down—they should fall on their heads.
But tarantulas do climb, albeit with difficulty, and researchers decided to find out how. So they collected the molted skins of several species of
tarantulas, including the lead author's own dearly departed pet, Fluffy (pictured above). The bottoms of their fuzzy feet, it turns out, are covered
with microscopic hairs, some of which serve as "spigots" for a sticky silk, which they only
turn on when they start to fall. Since most spiders produce silk from spinnerets on their abdomens, the finding might help explain how spiders evolved
so many uses for their silk, the researchers report in the June issue of The Journal of Experimental Biology. It also explains why tarantulas leave
little silky footprints wherever they walk.
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A Moon on Fire
The jovian moon Io harbors a globe-girdling pool of molten rock beneath its volcano-riddled surface. That’s the conclusion of a reanalysis of decade-old data from the Galileo spacecraft that once orbited Jupiter, reported online today in Science. Theoreticians had long predicted that Jupiter’s massive gravity must raise tides in Io that knead its solid but still malleable rock to produce heat until at least part of the interior melts. And planetary geologists had seen signs in the moon’s surface lavas that indicate that its 100 known volcanic hot spots are fed by a deep magma “ocean.” But high-flying volcanic debris frustrated space physicists’ attempts to use Jupiter’s powerful magnetic field as a probe of Io’s interior. Now researchers report that they have finally sorted through the interference to reveal a magnetic signature that Io could only produce if it contains an electrically conductive layer of magma—or crystal-laden magma mush—50 kilometers or more thick (thin orange layer) beneath its rocky crust. The find is reminiscent of the solar system’s earliest days, when most large, rocky bodies sported a magma ocean until they cooled down.
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Lizards Lounge in Their Labyrinthine Lairs
The great desert skink is the homebody of the lizard world. The Australian reptiles (Liopholis kintorei) dig elaborate burrows, which, scientists have now discovered, shelter closely related family members and can be occupied for up to seven consecutive years. These complex tunnel networks, which measure up to 13 meters across, feature multiple entrances and designated outside latrine areas where the lizards go to defecate. By trapping lizards and snipping off a tiny portion of their tails for DNA analysis, researchers found that adult desert skinks live in the same burrow with multiple generations of their children. Both parents and siblings pitch in to build and maintain their home, the team reports online today in the journal PLoS One. Although many species of birds and mammals exhibit such cooperative behavior, this is the first report of lizards constructing a family house. Desert skinks are fairly faithful lovers, which could help explain why families stick together. The finding may bolster the hypothesis that cooperation evolved in groups of genetically related individuals.
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Loving Life at a Hydrocarbon Seep
A 5-meter-wide chunk of carbonate minerals embedded in a seaside cliff in northern New Zealand has yielded fossils of a shelled microorganism that may have thrived only around the small, isolated, and far-flung sites where hydrocarbons such as methane or natural asphalt seep through the ocean floor, researchers say. Although the lump is a few meters above sea level today, analyses suggest that about 20 million years ago, the minerals formed at a seafloor site, then between 600 and 2000 meters deep, where methane seeped up through the ocean bottom. Most creatures inhabiting such seeps, including microscopic ones, also live in nearby waters. But at this site, more than 95% of the foraminifera, or shelled amoebas, entombed in the carbonates were Amphimorphinella butonensis, a species now apparently extinct that has been found at only one other site—a small, asphalt-infused patch of limestone in central Indonesia. The presence of this rare species at a second site associated with deep-sea hydrocarbon seeps suggests that the creatures were specifically adapted to live in the unusual environmental conditions at such sites—the first such species to be limited to such ecosystems, the researchers reported online May in Geology.
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T. rex as a Kid
Even the most terrifying meat-eating dinosaurs were children once, and now scientists have uncovered one of Tyrannosaurs rex's most immature
relatives—a 2 or 3 year old (7 or 8 in equivalent human years) whose skeleton is nearly intact. According to a paper published today in The Journal of Vertebrate Paleontology, the 70 million year old fossil belongs to Tarbosaurus bataar, an enormous carnivorous dinosaur of
the tyrannosaurid family that was the length of a four-story building from head to tail. Following an exhaustive anatomical analysis (see video of skull), the researchers
say this juvenile, which was about the size of an adult human, was not able to crush bone or exert strong bite and twisting forces with its jaw like
its parents. Thus, unlike adults who probably did not travel with them and dined on other large dinosaurs,
young Tarbosaurus likely hunted small reptiles. Such large dietary differences between a juvenile well past infancy and an adult are rare in the animal kingdom and unprecedented in the world of
dinosaurs, the researchers say. If paleontoloists didn't know as much as they do about Tarbosaurus, say the authors, they would think this
youngster belonged to a separate species.
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How Natural Is Your Cola?
Water, sugar, and caramel coloring are the main ingredients in most soft drinks, but some "natural" beverage makers add cola nut extract to the recipe—and extra cents to the price tag. Now, researchers in Italy have developed a method to test whether these premium colas live up to their billing. The team took 1 liter
of a particular naturally flavored soda brand and dumped in millions of tiny beads, each coated with a different sequence of amino acids. Some of the
amino acid combinations latched onto the cola nut proteins in the soft drink. The researchers then separated out the captured proteins and identified
them. When the team followed the same procedure with a liter of Coca-Cola, which does not claim to use cola nuts in its recipe, they found no protein
signature. The technique, published today in the Journal of Proteome Research, could help consumer groups test the authenticity of naturally
flavored sodas or other beverages, the researchers write.
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Why Is This Galaxy Lopsided?
A new image of the distant Meathook Galaxy, which gets its name from its dramatically warped profile, reveals widespread patches of glowing gas that
betray bursts of star formation. The pinkish and reddish clumps of glowing hydrogen, ionized by the powerful radiation of newborn stars nearby, can be
seen across most of the galaxy but are particularly prominent in the longer of the galaxy's two spiral arms, researchers report online today.
Astronomers previously have suggested that the asymmetrical shape of the Meathook Galaxy, dubbed NGC 2442 and located about 50 million light-years away
in the constellation Volans (also known as the Flying Fish), stems from gravitational interactions with another, as-yet-unidentified galaxy that passed
nearby. The same tidal forces that deformed the mass of stars probably disrupted clouds of gas in the galaxy, causing them to collapse and triggering
the spate of star birth, the researchers say.
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Why Bats Don't Like Rain
Some bats keep flying in a light drizzle, but they take shelter when there's serious rain. A new study published online today in Biology Letters
finds one reason why: Bats have to work harder to fly when their fur and wings are wet. In a series of trials in Costa Rica, scientists studied
Sowell's short-tailed fruit bats as they flew around a large octagonal cage. Sometimes they first dampened the bats with tap water; sometimes the bats
flew wet and in the rain.
Bats used about twice as much energy when they were wet as when they were dry, the team found. Flying in the rain didn't make a difference, which ruled out some kind of mechanical problem caused by raindrops hitting wings, nor
did the actual weight of the water. The scientists think that wet bats, like most wet mammals, are cold, so they have to work harder to stay warm. And
with water mussing their silky fur and dampening their wings, bedraggled bats might also be less aerodynamic.
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Smart Birds Live in the City
Now there's a scientific explanation for why Big Bird chooses to live in downtown Manhattan. For the first time, researchers have found evidence that the most successful urban bird species have bigger brains than
exclusively rural species, suggesting a greater adaptability to unnatural environments. By measuring the brain volumes of 82 different bird species
(corrected for body size) and comparing them against each group's ability to breed in 12 different urban centers in Europe, the researchers found a
strong correlation between large brains and city-dwelling. In their paper published in Biology Letters today, the authors suggest that this
phenomenon likely holds true for other vertebrates as well: street smarts help birds find innovative solutions to problems such as a lack of trees,
ubiquitous plate glass windows, and deciding whether or not to eat streetcart hot dogs off the sidewalk.
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Laser-Enabled CSI
Take note, crime scene investigators: Researchers may have found a way to figure out where a person has been—and even hints about what they've been
eating—simply by zapping their hair with
an ultraviolet laser. In one demonstration of the new set-up, reported online this month in Rapid Communications in Mass Spectrometry, the team
burned three 50-micrometer holes in a horse hair (above). Subsequent analyses of the vaporized material revealed variations in the carbon isotope
ratios incorporated into the hair as it grew. Those changes were caused by subtle changes in the horse's diet—for instance, the isotope ratio in
oats the horse ate 1 week ago may be quite different from the ratio in alfalfa it consumed last month, when the follicle was producing a different
segment of the same hair. Besides providing insights into dietary changes, analyses of the ratios of carbon, nitrogen, and oxygen isotopes in hair
samples from animals can provide hints about their migratory habits. For humans, such techniques could help discern changes in the recent travel habits
of a criminal suspect or help identify the place of origin for an unidentified set of remains.
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Cave Formations Reveal Dramatic Growth of Northern Alps
The Alps have grown substantially during the past 2 million years, but in some locales about two-thirds of that growth has been carved away by glacial erosion, according to a
new study which will be published next month in Geology. The evidence is locked in a stalagmite pulled from a cave (main image) in western
Austria. First, researchers used uranium-lead dating to determine the age of the 36-centimeter-tall cave formation (right image), which grew between 2.0
million and 2.16 million years ago. Then, they analyzed the ratios of oxygen isotopes in the stalagmite, which indicate that mineral-rich water seeping
into the ancient cave fell on a landscape several hundred meters lower than that overlying the cave today. Finally, they measured the ratios of carbon
isotopes in the formation's carbonate minerals, which hint that the cave, now near Earth's surface, was located about 1 kilometer underground when the
stalagmite was growing. Altogether, data suggest that the mountains have, on average, grown about 7.5 centimeters each century for the last 2 million
years, with erosion trimming about 5 centimeters off the top each century. Most current techniques for assessing uplift and erosion of mountains don't
work if the peaks are composed of carbonate-rich rocks, so analyzing ancient cave formations offers hope to scientists seeking to estimate such trends.
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Jurassic Spider Not So Itsy Bitsy
A new fossil discovered in the Daohugou Beds of northeastern China shows that a modern group of spiders, called golden orb-weavers or Nephila,
were on Earth during the Jurassic period about 165 million years ago. The fossil, Nephila jurassica, is a female, and if modern spiders are any
guide, was probably much larger than her male counterpart. With a 15-centimeter-plus leg-span, she's the largest fossilized spider ever found, researchers report online
today in Biology Letters. She appears to be closely related to the modern web-weaving Nephila spider of the same size. Well-preserved
spinnerets on the fossil's abdomen suggest that it, too, spun large, permanent webs: a weapon in an arms race that could have influenced the evolution of
insects and small birds that got caught in them.
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Worlds With Two Suns May Sport Black Plants
Plants that evolve on planets in a multisun solar system might look quite different from Earth’s mostly green foliage, researchers will report tomorrow at a meeting of the Royal Astronomical Society in Llandudno in the United Kingdom. To maximize energy absorption for photosynthesis, especially when the suns have vastly different colors or if at least one of the suns is dim, plants—or, more correctly, their extraterrestrial analogs—may use one or more types of light-absorbing pigments that absorb across a broad range of wavelengths, which would tend to make the plant appear black or gray (main image). Although the idea that planets that could host such life may sound far-fetched, such orbs may not be so rare: The team’s computer simulations indicate that Earth-like planets can exist in several types of stable orbits in multistar systems (inset). More than one-fourth of the sunlike stars in our galaxy and about half of the long-lived but dim, cool stars called red dwarfs are found in solar systems containing two or more stars, the researchers note.
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Some Dinos Liked a Midnight Snack
Some species of dinosaurs and ancient flying reptiles probably foraged at night, suggests
a new fossil study of bony structures found in the eyes of many reptiles and birds. In modern creatures that have such structures, the sizes and
proportions of these so-called scleral rings which reinforce the eye's outer tissues and surround the pupil, are reliable indicators of whether the
animals are active during the day, night, or both. The relatively small size and internal diameter of the scleral ring in the falcon-sized pterosaur Scaphognathus crassirostris (depicted in purple, main image), compared to the size of the creature's eye socket, indicate that this flying
reptile could see well only in bright light, researchers report online today in Science. However, the large internal and external diameters of
the scleral ring in the toothy, retriever-sized Velociraptor mongoliensis (top image) suggest that the predator hunted at night.
Although most flying reptiles analyzed for the study were active in daytime, four of the pterosaurs were apparently nocturnal and occupied ecological
niches similar to those of today's bats. The findings defy the common wisdom that ancient mammals skulked about unbothered by predators presumed to
have been active only in the daytime.
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A Vase Made From DNA
Scientists have fashioned perhaps the most elaborate piece of DNA origami
yet: a tiny three-dimensional vase just 70 nanometers tall. For 5 years, researchers have been able to create nanostructures out of DNA, but until now
most of the shapes have been fairly boring, like boxes or polygons, because they needed to be folded around a grid of DNA pegs or "pixels." In their
paper published online today in Science, researchers describe a new origami technique, in which they begin by forming rings of different radii
with DNA strands. They stack these rings on top of one another to form the basic 3D shape, and then insert "crossover points" to blend the DNA strands
into adjacent rings, holding the structure together. They hope that their vase, pictured above in an atomic force microscope image and a computer-generated image, could be used in
medicine to deliver drugs or enzymes to specific parts of the body.
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Dark Matter? Keep Looking
Once again, physicists have not found particles of dark matter—the mysterious stuff whose gravity holds galaxies together. Researchers working with
the XENON100 particle detector in the subterranean Gran Sasso National Laboratory in central Italy report today that 100 days' worth of data taking
turned up three events that could be dark matter particles smacking nuclei in the 62 kilograms of liquid xenon in their detector. But the scientists
expect roughly two false positives from ordinary particles, so the chances are that all three events are "background," the team explains in a paper
submitted to Physical Review Letters. The results show that other claimed dark-matter sightings were also spurious, the authors say. Physicists
remain hopeful that bigger detectors will provide proof positive of dark-matter particles within the next few years.
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Toads Keep Their Brains Germ-Free
Handling toads won't give you warts; in fact, it just might clean your hands. Although scientists have long known that the skin of fire-bellied toads
contains a variety of small antimicrobial proteins, or peptides, researchers have now found that the amphibians' brains harbor a vast array of these
germ killers as well. By performing genetic analyses and mass spectrometry on ground-up toad brains, the researchers found 79 different antimicrobial
peptides—the widest variety ever seen in the brain of any animal. When the researchers tested the peptides out on bacteria, viruses, and fungi, some
of them turned out to be very powerful germ killers. Their purpose, the researchers propose in the Journal of Proteome Research this month, is
to protect toads from any pathogens that can get through the blood-brain barrier. No word yet on whether a toad-brain based hand soap is in the works.
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Safe Sex, Duck Style
Male mallard ducks (Anas platyrhynchos) are famous for their long, spiraling genitalia. Now scientists have
discovered that they have something else to crow about. Mixing duck ejaculate with a common bacteria, Escherichia coli, researchers have found
that mallard duck semen kills bacteria. Semen from males with
more colorful bills harbored the greatest antibacterial activity, killing up to three times more bacteria than those with duller bills, the team
reports online today in Biology Letters. The finding suggests that female ducks may be drawn to brightly colored males not just because they're
more flashy, but because they spread fewer germs through sexual intercourse.
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Yellowstone Gets a CT Scan
Yellowstone National Park is indeed an electrifying place. Researchers have used observations of Earth's electromagnetic field collected at more than
100 sites surrounding the park to create a CT scan-like image of the plume of hot rock responsible for today's geysers and hot springs (main image) as
well as past volcanic activity in the region. Variations in the conductivity of rock underlying the region—which conducts electricity in some places
as well as seawater does (dark red, inset)—reveal zones rich in molten silicate rocks and hot briny fluids, the researchers report
in a forthcoming issue of Geophysical Research Letters. The plume may stretch more than 600 kilometers westward of the Yellowstone basin, the
new report suggests. In the past decade or so, several other teams of geoscientists, including one with one of the researchers making the new report,
have spotted the plume using seismic waves. The electromagnetic image of the plume is broader than the one derived from seismic data but doesn't extend
as deep, largely because the electromagnetic waves the study analyzed can penetrate only 300 kilometers or so of Earth's crust.
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Newfound Asteroid on Earth's Tail
Don't panic, but Earth has a celestial stalker. An asteroid discovered last fall moves in roughly the same orbit as Earth does. However, there's no
need for a restraining order. Computer models indicate that for the foreseeable future, the object (denoted with an arrow in the photo) will stay at
least 19 million kilometers away from our planet and, therefore, doesn't threaten a collision. Right now, the asteroid, dubbed 2010 SO16, is making one
of its closest approaches to Earth, researchers at the Armagh Observatory in the United Kingdom report in April's Monthly Notices of the Royal Astronomical Society. Relative to
Earth, the asteroid, which likely ranges between 200 meters and 400 meters across, moves in a horseshoe-shaped path that sometimes carries it to the
far side of the sun. Simulations suggest that unlike the paths followed by three other known asteroids in such orbits, 2010 SO16's orbit has been
stable for at least 250,000 years and will likely remain so for at least 200,000 years into the future.
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Kepler Watches Stellar Throbbing
Launched in March 2009, NASA's Kepler observatory has become synonymous with the search for extra-solar planets. But that's not all it's been doing up
in space. The spacecraft has also been recording the gentle pulsations of stars—the small variations in their brightness caused by sound waves
throbbing outward from the stellar core to the surface (seen in the yellow star in illustration). In the latest issue of Science, researchers
report measuring these pulsations for some 500 sun-like stars, which is
enabling statistical studies of stellar characteristics like mass, radius and age and test models of stellar evolution. In another paper in the same
issue, a different research team reports using Kepler data to detect a system of three stars, which includes a red giant star and two red dwarfs.
Although astronomers thought that the red giant would show sun-like oscillations caused by waves from within, they found that the star's pulsations
were being driven by the waxing and waning of gravity from the orbital motion of the two red dwarfs. Researchers hope to use these observations to gain
new insights into the formation of stellar systems, as well as the evolution of stars.
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Now That's a Big Number
Worried about having enough hard drive space to store all of your holiday pictures? Just be glad you don't have to cope with the 9.57 zettabytes—that's 9,570,000,000,000,000,000,000 bytes—of information that the world's 27 million business computer servers process each year. If you divided
9.57 zettabytes among the 3.18 billion workers that make up today's global labor force, then each person would receive around 3 terabytes of
information per year. That's enough to fill the largest external hard drive three times over. What's most worrying is that this number will likely
double every 2 years, according to researchers who presented their estimates at a
conference for data storage professionals in the United States in Santa Clara, California, today. Might be time for a reformat.
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Martian Mud Volcanoes
Mars-orbiting probes have spied hundreds of mounds, some up to 500 meters across and dozens of meters tall, inside an ancient crater near the planet's
equator. In the 15 April issue of Earth and Planetary Science Letters, researchers make the case that these enigmatic features (depicted in blue
in the main image) are
mud volcanoes. For one thing, the near-circular mounds weren't formed by molten-rock volcanoes because there are no deposits of volcanic ash or lava nearby.
Instead, the mounds contain boulders and other chunks of material apparently stripped from underlying layers of sediments (depicted in yellow-green),
which range from 200 to 500 meters thick. Also, most of the mounds inside the 90-kilometer-wide Firsoff crater (inset) are found on slopes inside the
crater rim and were likely created when mud under high pressure—which likely formed during a warmer, wetter phase on the Red Planet—oozed to the
surface through a network of cracks there. Other teams have claimed finding mud volcanoes elsewhere on Mars, but the researchers contend that the new
finds are the first that definitively link material in the mounds to underlying sediments.
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Green Eggs and Salamanders
It might sound like something out of a Dr. Seuss story, but biologists have long told tales of the green eggs of the spotted salamander. Ambystoma maculatum lays its brood in ponds each spring up and down North America. These marble-sized gelatinous sacs quickly turn green (bottom
left and top right images) as photosynthesizing algae grow around the developing embryo and feast on its waste. In turn, the embryo enjoys the oxygen
produced by the algae. Now scientists have discovered that the algae gets a little closer than they thought. Using long-exposure imaging, the
researchers detected algal fluorescence (main image) inside the developing salamander. This is the first case of an algae living symbiotically within a vertebrate, the team reports
online today in the Proceedings of National Academy of Sciences. How the photosynthesizing algae gets there, and how it survives inside the
tissues and cells of this predominantly nocturnal amphibian is still baffling to scientists. But one thing's for sure, the discovery means rewriting
textbooks to add salamanders to a short list of organisms, including coral and bacteria, that form symbiotic relationships with plants.
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The Earliest Touchdown
Three hundred million years ago, a flying insect skidded to a landing on a muddy patch of earth and preserved a 3.5-centimeter-long imprint for eternity. From the position of the legs, the curve of the abdomen, and the lack of wing marks, the researchers suspect that the imprint was made by an ancient mayfly that held its wings upright when at rest. Collected in southeastern Massachusetts, the fossil is the oldest known full-body impression of a flying insect, the team reports online today in the Proceedings of National Academy of Sciences. The ability of today's insects to skim the surface of water is thought to be a modern invention. But the discovery of tiny drag marks (see inset) that suggest that mayflies likely slide before stopping is at least enough to prompt some paleontologists to keep an open mind on the matter.
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Impacts Leave Marks on Rings of Saturn and Jupiter
Whizzing asteroids and comets have battered Earth and all the other solid bodies of our solar system over the eons, but the ethereal rings of the giant
planets seemed immune. No longer. In two papers published online today in Science, researchers report that comet impacts in recent decades have
left their mark on the rings of both Saturn and Jupiter. In August 2009, the orbiting Cassini spacecraft caught sight of 20-meter-high corrugations
rippling across 1500 kilometers of Saturn's inner C ring (regular, narrow
bright bands, above), which is only about 10 meters thick. The corrugations turn out to be one continuous wave spiraling outward like the groove in a
vinyl LP record. And in 2007, the New Horizons spacecraft on its way to Pluto imaged two wave sets spiraling through each other in the faint, dusty ring of Jupiter. One Jovian wave appears to be still on the
move 13 years after fragments from comet Shoemaker-Levy 9 hit the ring on their way
to pummeling Jupiter in 1994. But for any impacting object to hit a tenuous ring hard enough to tilt it and set off such reverberations, both teams
agree, it would first have to disintegrate into a cloud of fine debris that can hit a broad area of ring. That's just what Jupiter's gravity did to
Shoemaker-Levy 9.
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The Oldest Buttercup Yet
Darwin called the origin of flowering plants an "abominable mystery." They appear in the fossil record and immediately grow abundant and varied,
creating a problem for his theory of slow but continuous change. The unearthing of a new fossil in northeast China, described online
today in Nature, could explain the apparent contradiction. The ancient flowering plant, Archaefructus liaoningensis, resembles a
modern-day buttercup, with slender stems and three-lobed leaves. Its discovery pushes back the date of when flowering plants diversified to around 127
million years ago, during the early Cretaceous period. That's a couple of million years earlier than Darwin had previously thought, suggesting that
these ancient blooms had longer to evolve than he suspected.
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Some Aggressive Akitas Are Roid Ragers
If you want to know whether your new fluffy puppy will be a cuddly friend or snarl at and bite anything that moves, you might want to check out the
length of its genes. Researchers at the University of Tokyo in Japan asked 100 Akita owners to fill out questionnaires about whether their pooches were
naughty or nice. When they looked at the doggies' DNA, the scientists found that the meanest males more often had a shortened gene for a receptor that
responds to various male hormones. The gene variant produces a form of the protein that has previously been shown to respond more strongly to
testosterone. This is the first time that canine aggression has been associated with genetic differences in the male hormone receptor, the researchers report in Biology Letters this week. Over half of the
Akitas they studied had this variant. Yet mean female dogs weren't more likely to have the short variant than the gentle dogs, suggesting that females
respond differently to these hormones.
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Jet Contrails a Big Global Warmer
The white, cloudlike trails left in the wake of high-altitude jets are warming the earth more than the planes' carbon-dioxide emissions, a new study
suggests. Although some so-called contrails, which are simply clouds of tiny ice crystals condensed from the moisture in aircraft exhaust, evaporate
quickly, many linger for hours and spread across the sky. A new model that can estimate the formation and persistence of contrails suggests that as
much as 6% of eastern North America can be covered with these humanmade clouds. In central Europe, coverage can reach 10%, researchers report today in Nature Climate Change.
Just like natural cirrus clouds, contrails block infrared radiation emitted from Earth's surface, and the increased coverage provided by contrails
boosts cloud-induced warming. On a worldwide average, contrail-induced cloudiness traps an extra 31 milliwatts of energy per square meter. Previous
analyses suggest that the carbon dioxide emitted by aircraft since the beginning of the jet age traps 28 milliwatts per square meter.
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Black Holes Are Messy Eaters
Intense magnetic fields near a black hole known as Cygnus X-1 may be stripping electrons from infalling material just milliseconds before it passes a point of no return and disappears within the black hole, according to new observations by the INTEGRAL gamma-ray observatory. The fields then channel these electrons away, allowing them to escape via powerful jets of material and radiation. The key evidence—the polarization of gamma rays emitted by material just before it is swept into the black hole—is reported online this week in Science. Because gamma-ray photons form only a small part of the radiation emitted by the black hole, researchers had to stitch together dozens of observations made by an Earth-orbiting telescope over the past 8 years to discern the polarized radiation. Although scientists still aren't sure how the jets spewing from the poles of black holes (see image) originate, the new image—one equivalent to taking a single time-lapse photo more than 5 million seconds, or more than 2 months, long—indicates that the magnetic fields near Cygnus X-1 may be hundreds of thousands of times stronger than Earth's.
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Ancient Creature Was a Saber-Toothed Vegan
Saber-toothed predators are rare, but vegetarians sporting such fangs are members of an even more exclusive club. Scientists have now described one
such creature, a short-snouted, tapir-sized animal known as Tiarajudens eccentricus. The so-called therapsid, a close relative of the creatures
that eventually gave rise to mammals, lived about 260 million years ago in an arid region of what is now Brazil. It had molarlike teeth suitable for
grinding a fibrous diet of ferns, leaves, and stems. But unlike most of its vegetarian kin, Tiarajudens also sported sturdy saber-like teeth that measured at least 12 centimeters long (part of
the species’ name translates as “unusual tooth.”) Those fangs didn’t have serrations along their edges and likely weren’t
used for chewing, say the paleontologists who describe Tiarajudens fossils online today in Science. Instead, they suggest, the
distinctive teeth could have been used to deter predators, to spar with rivals, or as a way for individuals of the species to easily recognize their
cohorts.
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Cold 'Star' No Hotter Than a Summer's Day
Stars are stars, and planets are planets, and never the twain shall meet, right? Not quite. Brown dwarfs—so-called failed stars that are too small to sustain the stable burning of hydrogen—fall somewhere in between stars and planets when it comes to mass and temperature. Now, researchers have found two brown dwarfs that are colder than any previously seen—so cold and so small that they are almost like giant planets. In a paper published 20 March in The Astrophysical Journal Letters, a team reports on a brown dwarf about 63 light-years away whose temperature is barely 300 kelvin. That's 200 K cooler than the previous record holder and about as warm as a bright summer day on Earth. In a second study, to be published in an upcoming issue of The Astrophysical Journal, researchers describe another very cold brown dwarf (shown here in an infrared telescope image), whose estimated temperature is about 370 Kelvin. The two objects could be the first examples of a proposed class of ultra-cool brown dwarfs known as the Y-class. And because they are almost as cold as "gas giant" planets—Jupiter is about 150 K—studying them could offer a better handle on what the atmospheres of alien worlds look like.
For more information about these discoveries, see the 18 March issue of
Science.
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MESSENGER Arrives Safely at Mercury
Late yesterday evening, eastern U.S. time—after 6½ years in space, almost 8 billion kilometers traveled, six orbit-altering flybys of planets, and 15
minutes of blasting its main engine, the MESSENGER spacecraft finally slipped into orbit around Mercury. The smallest, innermost planet is the last of
the classical, naked-eye planets to get an orbiter. Tagged with the most contorted of acronyms (standing for MErcury Surface, Space ENvironment,
GEochemistry, and Ranging), MESSENGER will probe everything from the mineral elements the sun continually blasts off the planet's surface to its
relatively huge metallic core, which occupies nearly half of its volume. Also of interest are the subsurface ice deposits thought to linger near the
poles of the sun's nearest neighbor. MESSENGER's seven scientific instruments, battened down for the rocket burn (after taking images during three
earlier Mercury flybys), will be turned on and checked out for the start of science observations on 4 April. Team members expect the orbiter to return
its first images later this month.
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Long-Awaited Titan Rains Arrive
On descending toward the surface of Saturn's haze-shrouded moon Titan in early 2005, the Huygens lander spied all manner of channels and canyons that
had to have been carved into the ice of the deeply frigid satellite by rushing liquefied methane. But there were neither methane rains nor even methane
clouds seen in Titan's "tropics" where Huygens landed. Patience has paid off, however. Now that southern hemisphere winter on Titan is giving way to
spring (a Titan season is more than 7 Earth years long), equatorial rains have arrived, according to a report published online today
in Science. By monitoring Titan in haze-penetrating infrared, researchers spied equatorial clouds (white in this picture) last September and
October using an instrument on board NASA's Cassini spacecraft that is still orbiting Saturn. And after the September clouds had passed, they found
that an equatorial region had darkened. That's just what methane rain would do if it formed puddles or at least wetted the surface. The spring rains
are reassuring atmospheric scientists, who had called for such seasonal changes, and confirming that equatorial erosion continues on Titan.
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Mapping the Tsunami
The magnitude-8.9 quake that struck Japan at 2:46 p.m. local time on Friday spawned coast-slamming tsunamis that will cross the Pacific in less than 21
hours. The tsunami first reached a monitoring buoy just minutes after the quake occurred, and soon thereafter scientists released a forecast of wave
heights and arrival times. Colors in this image depict peak wave heights. Near the undersea source of the temblor, about 375 kilometers north-northeast
of Tokyo, and southeast of that epicenter, where much of the quakes energy was focused, the height of the tsunami wave likely exceeded 2.5 meters
(depicted in black). But across most of the Pacific, the open-ocean height of the waves, which race across the sea at jetliner speeds, probably
remained less than 20 centimeters (yellow and orange).
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Shark Survey Yields a Worrisome Surprise
The first survey of great white sharks off the coast of central California has turned up fewer of the top predators than biologists had expected. To
count the sharks, scientists braved ocean swells in small boats and used a seal decoy to lure sharks in for a portrait (see photo). From 321
photographs of dorsal fins, which are as unique as fingerprints, they identified 131 individuals. They estimate that the entire population consists of
219 adult and immature sharks. That's a substantially smaller population than that of another large marine predator whose numbers were reduced in the
19th and 20th centuries by whaling and other human activities: killer whales, which number around 1145 in the same area. The researchers worry that
other great white populations may also be smaller than expected, and they urge further protections for the species—which the International Union for
Conservation of Nature now classifies as only vulnerable to extinction. The study appears in the current issue of Biology Letters.
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Capuchins' Screwy Solution to a Termite Problem
Anyone who has tried to eat ice cream with a biodegradable spoon can sympathize with the blonde capuchin monkey: It's hard to eat when your utensils keep bending or breaking. So, tired of finding new tableware every time they wanted termites for dinner, these critically endangered Brazilian monkeys figured out a clever solution that hasn't been observed before in any species. Balanced on two feet and their prehensile tails, capuchins tap a nest of termites with one hand to dislodge the bugs and then pierce the nest with a stick, screwing it in so that the stick doesn't break. Then they lick the delicious termites off the end. When human researchers aped the capuchins' methods, they found that the combination of banging the nest and rotating the stick retrieved significantly more termites. Their paper, published today in Biology Letters, doesn't mention whether the researchers thought they tasted any better this way.
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Mars Crater Gouged by Multiple Impacts
High-resolution images released today by the European Space Agency reveal new details about an unusually elongated crater on Mars that may have been blasted by several objects striking the planet's surface at a shallow angle. The unnamed crater, located in a heavily blemished portion of the Red Planet's southern hemisphere, is about 78 kilometers long, approximately 25 kilometers across at its widest point, and about 2 kilometers deep. Two distinct blankets of material blasted from the impact zone suggest that at least two projectiles, possibly fragments of a once-intact body, gouged the crater. Three particularly deep spots in the crater (depicted in blue, inset) bolster the notion of multiple impactors, as does the presence of another elongated crater nearby that has a similar alignment. Scientists first proposed in the early 1980s that elongated craters such as the ones seen on Mars could have been formed by pieces of a fractured object following the same trajectory. In 1994, more than 20 fragments of a comet slammed into Jupiter, providing dramatic proof that such events could happen.
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The Mystery of the Absent Sunspots
The sun is usually a predictable beast, at least as far as its sunspot cycle goes. Every 11 years or so, the sun's magnetic activity peaks and then troughs, resulting in relatively high and then low numbers of dark spots and flares on the solar surface. But in the cycle that has just finished, the trough went on for much longer than normal, with more than twice as many days without sunspots compared with previous cycles. To figure out what caused this, researchers used a computer simulation of the churning hot plasma inside the sun. As each cycle progresses, the movement of this plasma (black loop) shifts the solar magnetic fields (gold strands)—from which sunspots erupt—from the sun's midlatitudes to its equator. An extended minimum occurs whenever the plasma moves quickly at the beginning of a cycle—preventing a large buildup of magnetic fields—but then slows down toward the end, delaying the onset of the next cycle, the team reports online today in Nature. This knowledge won't help in predicting individual solar storms, the researchers say, but it should give scientists a better idea of how stormy the sun will be in the years to come. And that should help to limit the worst effects of storms, be it damage to satellites in orbit or harm to people flying close to the poles.
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Worms Are Divided After All
It turns out that worms really are deeply divided. In the mid-19th century, French naturalist Jean Louis Armand de Quatrefages de Bréau split worms into wigglers—which crawl and swim to their hearts' content, such as the marine ragworm (left)—and the more sedentary, typically tube-dwelling nonwigglers, such as the earthworm (right). However, early genetic studies called this classification into question. They indicated, for example, that the wigglers weren't that closely related to one another; instead, their physical similarities were the result of their adapting to similar lifestyles and environments. Now more comprehensive genetic evidence, reported online today in Nature, shows that de Bréau was right after all. Analyzing 231 genes from 34 different annelids, otherwise knows as ringed worms, researchers have shown that wigglers and nonwigglers do indeed represent two different evolutionary groups. What's more, the team found that the split between the two groups happened very early in worm evolution; the exact date isn't known because the soft bodies of worms don't preserve well as fossils. Wigglers kept their bristled appendages for moving around and foraging, whereas nonwigglers lost them as they evolved to stay put in their burrows to eat sediments and plankton.
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Dark Shells Make for Mean Tortoises
The next time a tortoise crosses your path, check out his shell. If it has lots of dark patches, give him a wide berth. When a team of researchers
pitted two male Hermann's tortoises against each other, the one with more dark splotches on his shell was more apt to pick a fight. Heavily splotched tortoises also weren't as shy about approaching a potential predator—in
this case, a human—to snatch a proffered apple, the team reports in an upcoming issue of Animal Behaviour. Color and aggressiveness may be
genetically linked, the researchers say, with the same gene or set of genes coding for both traits. Or, higher amounts of the pigment melanin allow
tortoises with more black shell spots to absorb extra sunlight to keep their body temperatures up, which may leave them more energy to throw into
impudently defending their territory.
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Gene Therapy Dries Up Binge Drinking Rats
Even rats can't resist an open bar. When researchers provided a group of the rodents with unlimited free booze, letting them binge on 10% lab ethanol
from their water bottles in "90-minute drinking sessions" for 3 weeks, the rats quickly developed a taste for the alcohol and became dependent on it.
The team then injected an RNA molecule into the rats' amygdalas, the region of the brain involved in emotional responses. The molecule blocked a gene
that codes for a receptor for GABA, a brain signaling molecule. After the treatment, the rats stopped drinking almost immediately, although they started up again after about
a week, the team reports online today in the Proceedings of the National Academy of Sciences. Examining the rats' brains, the researchers found
a change in the expression of a number of genes, some of which had previously been linked to alcoholism in humans. Blocking these genes using RNA
molecules, known as RNA interference, could be a potential treatment for alcoholism, they say.
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'Keep It Down!' Says the Pygmy Killer Whale
When you're a little lost whale, noisy areas can be a real problem. Whales use their hearing more than any other sense to navigate, so when two pygmy killer whales beached on a Florida shore,
the marine hospital that rescued them gave them a free checkup. There, researchers performed CT scans of the whales' heads and reconstructed 3D
models of their brains (inset) to better understand their hearing architecture. Next, they played high-frequency sounds at different amplitudes and
carried out brain scans to pinpoint which brain regions were most responsive to loud noises. In their report, published today in The Journal of Experimental Biology, the researchers warn that noise pollution—as well as chemical pollution—could deafen whales. The
findings might someday help rescuers test whether the lost cetaceans might be deaf before releasing them back into the wild.
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Tough on Crime? Depends on the Metaphor
Just one word could change how you think about crime, according to a
study published today in the journal PLoS ONE. Interested in how—and whether—we use metaphors to solve real-world problems, psychologists asked 253
people how they would deal with illegal activity in Addison, a fictional city where crime was rising at an alarming rate. Before proposing solutions,
the participants read that crime was either a "beast" or a "virus" that was ravaging the city. That small change in metaphor made a big difference. Seventy-one
percent of those who read about crime as a beast suggested tough strategies such as calling in the National Guard, while those who read about crime as
a virus were split: 54% favored tough approaches while 46% favored "treatments" such as improving the economy. The effect of metaphor was about twice
that of political ideology: Republicans were only 8% more likely than Democrats to propose tough solutions—something you might savor next time a
politician feeds you a line.
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How Arthropods Got Their Armor
Fossils of an ancient, 20-legged marine creature suggest that arthropods—a group that contains crabs, spiders, and insects as well as the long-extinct
trilobites—developed exoskeleton armor on their legs before they developed hard shells on their bodies. The species, Diania cactiformis, had a
soft body but sported ten pairs of hard-shelled legs rimmed with sharp spines, leading researchers to nickname it "the walking cactus." Fossils found
so far show no signs of eyes or jaws, so the animal, which measured about 6 centimeters long and lived about 520 million years ago, may have fed on
tiny plankton or on organic detritus in seafloor sediments. Diania is now the closest known relative to arthropods, and the creature's
discoverers contend online today in Nature that its partially armored configuration—the first such transitional form found in the fossil
record—provides evolutionary clues about how arthropods came to develop a full coat of armor.
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Why Was the New Zealand Quake So Devastating?
Size matters with earthquakes, but the modest-sized temblor that struck Christchurch on the South Island of New Zealand on Monday dramatically
demonstrated that there's much more to seismic destructiveness than just magnitude. Monday's magnitude-6.3 quake was just an aftershock to the
magnitude-7.0 quake of 3 September 2010, which was 11 times more powerful. No one died in the big one, but it was about 50 kilometers west of the city.
Monday's aftershock, however, was within only a few kilometers of the center of Christchurch and only half as far beneath the surface. That close to
the rupturing fault, almost a third of a million people felt severe to violent ground shaking, the U.S. Geological Survey estimates. And because the
smaller quake struck at midday, those residents were massed in larger buildings that were likely to kill victims if they collapsed. September's quake
hit in the early morning when most people were at home.
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Marine Mud Is High in Fish Poop
Will you still enjoy feeling the beach between your toes this summer knowing it's partly fish feces? In a paper published online this week in the Proceedings of the National Academy of Sciences, researchers report that 14% of the calcium carbonate that makes up the muddy floors of shallow
tropical seas is fish poop. Fecal samples from 11 common tropical fish, including
barracudas and snappers, reveal that calcium carbonate forms a key component of the excrement. The team estimates that every year, tropical fish excrete
6.1 million kilograms of calcium carbonate, equivalent to the weight of 1000 adult elephants, over an area of 111,577 square kilometers. Each fish may
even have its own unique "fecalprint", with specific sizes and shapes of calcium carbonate crystals (as seen in the black and white image), which could allow future
oceanographers to analyze an ocean's mud to track changes in the numbers and diversity of fish species.
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*This item has been corrected to reflect that every year, tropical fish excrete 6.1 million kilograms of calcium carbonate.
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Ancient 'Seaweed' Rewrites History
The discovery of leaf-thin, seaweed-like fossils in China nudges back the moment when ancient life went from microscopic to merely tiny. At 600 million
years old, the new fossils—called the Lantian Formation—are 27 million years older than the so-called Avalon fossils found in Canada and England,
which, until now, were the earliest known fossil assemblage of multicellular life. The new specimens, some resembling modern day seaweeds, represent 15
or so photosynthetic algae researchers report online today in Nature. Unlike the Avalon fossil organisms, which thrived in deep-water environments, these ancient "seaweeds" lived in shallow marine seas.
That means paleontologists need to rethink their theory that oxygenation of the deep oceans triggered the rise of more complex organisms.
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A Spider That Likes Stinky Socks
Arachnophobes everywhere will be heading to the laundromat when they hear this. Researchers have found that an East African spider, Evarcha culicivora, is attracted to your stinky socks. By presenting the spiders with a pair of socks worn continuously for 12 hours and a pair
of identical unworn socks, researchers showed that the arachnids prefer the smell of human feet. Luckily for us,
it’s likely that the spider’s odor detection has evolved not to find humans, but rather to catch the mosquitoes that carry our blood,
researchers report online today in Biology Letters. Still, it might not be a bad idea to take your socks off before bed.
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Too Sexy? Too Bad
Sorry, ladies, a world full of Johnny Depps is just not sustainable. Too many attractive males, and evolutionary pressures start to select against the
best-looking, researchers report online today in the Proceedings of the National Academies of Science. The researchers genetically engineered a
group of male flies to release highly attractive pheromones and then released a large number of them into a colony so that they greatly outnumbered
average males. Predictably, the females went for the sexier flies—at least at first. After seven generations, however, the numbers of attractive and
average flies had leveled out. The authors conclude that being overly attractive must carry a disadvantage, similar to how a male peacock's
large, colorful tail hinders its ability to flee and hide from predators. And that limits how many handsome men can exist in a population.
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Coral Time Sex to the Moon
The romance of a full moon sometimes gets the better of Acropora palmata. The 2-millimeter-tall polyp, which forms vast coral reefs in the Caribbean Sea, holes up in its marine fortress and waits for the moon to shift from its usual blue hue to a redder glow. Then it waits a bit more. If this red glow is followed by several days during which no moonlight is visible—an event that occurs only in the days following a full moon—these marine creatures know it's time for some serious synchronized sex. They release millions of eggs and sperm within a period of 20 minutes, ensuring that some young will survive parrotfish and other predators, researchers report this week in The Journal of Experimental Biology. That may explain why pilots often see red, 10-kilometer-long slicks of coral gametes a couple of days after a full moon.
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*This item has been corrected 14 February. This coral is not the Acropora millepora and forming reefs in the Southern Ocean, but rather the Acropora palmata in the Caribbean Sea.
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Egg Protein Throws Squid Into a Rage
Come mating time, male longfin squid (Loligo pealeii) get feisty. One touch of a female's egg sac and they go ballistic, grappling any other male within reach. Now scientists have identified the chemical trigger that sets them off. After exposing males to a variety of different egg sac proteins, they isolated one—called Loligo β-microseminoprotein—that drove the squid crazy. Human and mouse seminal fluid contain a similar protein, which is thought to somehow protect sperm, but its true function is unknown. β-microseminoprotein is the first aggression-triggering compound found in marine animals, the researchers reports this week in Current Biology. They suspect it prevents males from wasting their combative energy. After all, why bother fighting another male for a female unless she is fertile?
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Swordtail Pee Is the Aphrodisiac of the Sea
When your mom told you not to pee in the ocean, it could just be because she didn't want lovesick female swordtail fish flocking to you. Male swordtail
urine may be full of pheromones that drive the ladies crazy, researchers
report today in PLoS ONE. By injecting swordtails with a fluorescent dye that makes their urine glow under ultraviolet light in an aquarium, the team
found that males were more likely to leave a warm spot just upstream of where the females were gathered. Chemical communication in fish and other
undersea creatures hasn't been extensively studied, but if toxins in the water garble these important signals, they could disrupt fish reproduction and
harm marine ecology. So while it may be bad manners to pee in the sea, it's even worse to pollute it.
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Bats Are Social Networking Rockstars
They can't use Facebook, but bats still manage to keep in touch with their social network. Bat colonies, which are made up of a few dozen members, split and reform many times throughout the year as individuals go off to roost in small groups or hibernate alone during the winter. But researchers have found that female bats, like humans and elephants, form subgroups that stick together over long periods of time. In a study published today in the Proceedings of the Royal Society B, researchers marked bats from two colonies with data loggers and tracked their nesting behaviors over 5 years. They found that it's not just family members who stay together; a network analysis showed that these girls' clubs were made up of bats from many different lineages and age groups. (Male bats are always solitary.) The researchers propose that bat society probably benefits from cooperative behaviors such as grooming and communication, which are always more fun with your girlfriends.
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Why Some Penguins Wear a Blue Tuxedo
Feeling small and blue today? Eudyptula minor goes through its whole life that way. This Australian bird—the smallest of all penguins at around
30 cm high—sports a notable blue tint in its feathers, hence its common name, the Little Blue Penguin. Using high-powered microscopes, researchers
have now discovered that nanometer-sized fibers in the bird's wing feathers provide the unusual blue hue. Made from keratin, the same material as human
hair, these nanofibers are packed together like bundles of uncooked spaghetti, the team reports online today in Biology Letters. The penguin's
color is due to blue light that is scattered when it hits the fibers, while all other wavelengths of light just pass through the feathers. This is a
new mechanism for giving feathers a blue color, the authors say; similar nanofibers are found in the blue skin of other birds, such as Emus, but those
fibers are made of collagen. What advantage the colorful feathers provide for Little Blue remains unknown, but they certainly aren't being caught dead
in the same black and white tuxedo as most of their relatives.
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Snake Legs—Going, Going, Gone
Snakes evolved from four-limbed ancestors, and scientists have long wondered how they lost their legs. A new type of CT scan of a 95-million-year-old fossil suggests how genetics stunted the limbs’ growth. Using a newly developed x-ray technique called synchrotron-radiation computed laminography, researchers probed details of the vestigial hind limbs of the ancient marine snake Eupodophis descouensi. Each pixel in images of the rock-cloaked bones was barely more than 30 micrometers across. By virtually reconstructing an 0.8-centimeter-long limb, layer by thin layer, the researchers found that—unlike the snake’s vertebrae and most of its other bones—the leg bones didn’t have thick-walled shafts. That’s a clue, the researchers say in a paper scheduled to be published online today by the Journal of Vertebrate Paleontology, that the limbs were small because they grew either much more slowly or for a much shorter time than did the other bones.
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Japanese Volcano Filled to the Brim
All eyes on Japan’s Kyushu Island are on the growing lava dome of the volcanic peak Shinmoedake, which has been erupting off and on since 26 January. This image captured on 4 February shows the lava nearly filling the 700-meter-wide crater. Scientists are predicting that eruptions could grow stronger and go on for months. The peak's last major eruption continued for a year and a half in 1716 and 1717. The University of Tokyo's Earthquake Research Institute is posting regular updates of its observations, including photos taken from the air (first in Japanese and a few days later in English). Kagoshima Prefecture posts pictures from a neighboring peak that are updated every minute. Ash from the volcano, although minor compared with what spewed from Iceland's Eyjafjallajökull last year, has disrupted flights and buried fields of winter vegetables. More than 1000 residents evacuated the rural area during the first eruptions, but most have returned. There have been no deaths or serious injuries so far.
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Fly Brains Now in Technicolor
Some flies' brains and eyes might be filled with psychedelic colors, but it's not from spending too much time at Burning Man. Using DNA from naturally
glowing jellyfish, two independent groups of researchers have found a way to color-code the 100,000 neurons in the fruit fly's brain and eyes so that
they can track what each cell does. Building on techniques first developed for mice, the researchers gave the insects genes for a red, a green, and a
blue fluorescent protein. The genetic control system they devised spurs each cell to make a different amount of each of the three proteins. Like the
red, blue, and green pixels on a TV screen, the combination of the three proteins causes each cell to glow a unique color. These two techniques, called Brainbow and Flybow and reported online today in Nature Methods, will allow researchers to trace how individual neurons develop and form connections with one another.
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Tiny Organism, Big Sequence
Diving into a lake next summer you could swallow hundreds of Daphnia pulex, a one-eyed, algae-sucking water flea. The creature has long
captivated biologists with its ability to shift between asexual and sexual ways of life and survive for decades frozen at the bottom of a lake. But it
is best known for its sensitivity to toxic chemicals, which helps ecologists monitor water quality in ponds and lakes. Now researchers have a chance to
figure out how the water flea works, thanks to its newly sequenced genome, reported online today in Science. One-third of the water flea's nearly
31,000 genes are unique and seem to respond to predation, exposure to toxicants, and bacteria. This has titillated geneticists and ecologists alike,
who spy an opportunity to understand which genes are responsible for some of the animal's peculiar talents, such as growing protective tail spines,
helmets, and neck teeth in response to the chemicals produced by predators. So when you gulp that mouthful of lake water, you can have the satisfaction
of knowing that you have not only just swallowed a fully armored crustacean, but the first of its kind to have its genome sequenced.
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Battle of the Galactic Bulge
Large galaxies, like our own Milky Way, are thought to arise when lesser galaxies smash together and merge. But galaxy NGC 3621, shown here in an
optical image released today by the European Southern Observatory in Chile, seems to have missed
the drama. Located 22 million light-years away in the constellation Hydra, NGC 3621 is a spiral galaxy but lacks a central bulge of stars. Such bulges
reside in most spiral galaxies and often resemble the yolk of an egg. They typically form after a galactic collision, when the smaller galaxy dumps
stars into the central region of the larger one. Somehow, though, NGC 3621 has managed to remain bulgeless, suggesting it never experienced a major
galactic merger and thereby contradicting the idea that spirals grow by gobbling their lesser neighbors. The galaxy is part of a growing list of bulgeless spirals that challenge current models of galaxy formation.
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Human Handedness Is for the Birds
Whether you're a righty or a lefty, parrots may be able to tell us why we've come to prefer one hand over the other. In a series of experiments,
researchers watched as 322 parrots from 16 different species attempted to grab an object—a toy or a piece of food—with their feet. Since the birds'
eyes are on the sides of their heads, they can't look straight ahead like we do; instead, they have to cock their heads to one side. But like us,
individual parrots show a strong preference for one limb or the other: The researchers noticed that a "left-handed" bird would cock its head to the
right to give its left eye a better view. It would then grab the object with its left foot, probably because this was the easier foot for the left eye
to track. If early animals had eyes on the sides of their heads like birds do, their need to use either one eye or another to grasp objects may have
led to the evolution of handedness, the researchers suggest
online today in Biology Letters.
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Meet the World's First 'Dark Sky Island'
Sark is an astronomer's paradise. The smallest of the four landmasses in the United Kingdom's Channel Islands, it has no paved roads, no cars, and no
public street lighting. Thus it sports precious little of the light pollution that bedevils those seeking a clear view of the night sky. Today, the
Tucson-based International Dark-Sky Association (IDA), which works to boost awareness of light pollution and its effects, recognized these qualities by
designating Sark the world's first "dark sky island." The island (inset) is home to about 650 residents, and many of Sark's homeowners and businesses have modified their lighting to minimize the amount of
light spilling upwards, says Steve Owens, a member of the IDA committee that identifies and recognizes sites with suitably dark skies. With the new
recognition, he notes, Sark will likely see a boost in tourism, especially among amateur astronomers who might visit to take advantage of the island's
crisp, clear skies during winter months, perhaps to catch a spectacular view of the Milky Way (main picture).
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Copycats Make Democrats
Is someone imitating you? It might make you more likely to vote for a Democrat.
Psychologists asked 62 students to talk to someone disguised as another student who, in some cases, subtly imitated the volunteer's facial expressions,
head movements, body posture, and gestures. Of the 33 students who were mimicked, 28 reported they would vote for a left-leaning party if an election
were held right then, about 10% more than had previously voted for a politically left party. Of the 29 students who weren't mimicked, 18 said they
would vote for a left-leaning party, 10% fewer than had previously voted for such a party. Other studies have shown that mimicry makes people more
empathetic and more likely to focus on their relationships with others. That may translate into voting for more liberal parties, the team reports online this month in Experimental Psychology. Don't expect mimicry as a
campaign tactic too soon, though. The authors haven't yet studied whether a politician mimicking you has the same effect.
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Homing Pigeons Follow Their Noses
Next time you have a cold, be glad you're not a messenger pigeon carrying important orders over a battlefield. Breathing through both nostrils,
especially the right one, is essential to these birds' famed ability to fly away home, scientists report today in the Journal of Experimental Biology. The
researchers saddled a group of homing pigeons with GPS tracking devices, placed a rubber plug in either their right or left nostrils, and released them
25 miles outside of their home in Pisa, Italy. Pigeons with their left nostrils blocked had a little more trouble navigating than clear-nosed pigeons,
but eventually made it home. Birds with their right nostrils blocked made it back, too, but they stopped more often and took an even more circular
route than the others. The researchers believe that the birds needed time to gather more smells and construct a map based on odors in the wind. And the
finding that the right nostril is the better sniffer suggests that the right and left hemispheres of bird brains have different functions.
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Dad's Odor Splits a Species
Some girls want a guy who looks like dear old dad. Stickleback fish want one who smells like him. Researchers have found that in two species of the fish from British Columbia's Paxton Lake, daughters learn who to choose as a mate based on their father's smell, a form of sexual imprinting. One type of stickleback lives in deep water; the other, in waters close to shore. Females of both types lay their eggs in an algae nest the male builds. He then cares for the eggs and fry, as this deep-water form of stickleback is doing above. In laboratory tests, daughters chose mates that smelled like their fathers, researchers report online today in the Proceedings of the Royal Society, B. That keeps the two species apart sexually, helping to reinforce their ecological separation. It's some of the first evidence, the authors say, that sexual imprinting can drive speciation.
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Oversized Exoplanets Inflate Themselves
The 500 and more known exoplanets are plenty weird and wonderful, thanks in large part to many of them orbiting perilously close to their stars. The extreme
heating can drive supersonic winds and melt rocky surfaces. But even such blistering temperatures can't account for Jupiterlike exoplanets that swell
to diameters far larger than can be explained by any heating from their stars. Now researchers have found signs that inexplicably large exoplanets are
generating their own electrical currents that heat their interiors. In a paper posted last week on
arXiv.org, researchers found a tendency for known exoplanets to be larger than expected if their stars have driven their outer temperatures to at least
1500K. That's the temperature needed to ionize trace elements like sodium and potassium and make the planet's gases able to conduct an electrical
current. High-speed winds can then carry the ionized gas through the planet's magnetic field to generate loops of current extending deep into the
interior. Resistance heating there like that in a toaster or electric oven can then heat the whole planet and keep it puffed up.
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A Dino With Just One Finger
Meat-eating dinosaurs were very good at finding food, thus their evolutionary success over some 165 million years. But during their time on earth, they
kept losing something that might seem important: their fingers. The earliest carnivorous dinosaurs had five fingers, although only four were actually
functional. Many later meat eaters had only three, and evolution left the mighty Tyrannosaurus rex with only two. Now researchers have unearthed
the first known dinosaur with only one finger. The new single-digit species, named Linhenykus monodactylus and described online today in the Proceedings of the National Academy of Sciences,
was found in a roughly 80 million year old rock formation in Inner Mongolia. Linhenykus,
which was probably about a meter tall, belongs to a family of dinosaurs called alvarezsauroids, which some researchers once thought were early
flightless birds but which are now widely recognized as true dinosaurs. The team suggests
that the single, clawlike digit was an adaptation for digging, perhaps for insects such as termites.
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Superstars Team Up in the Southern Cross
This infrared image from NASA's Spitzer Space Telescope shows what may be the most luminous group of superstars in the entire Galaxy. Such
groups—named OB associations for the O and B spectral types of their hot, blue suns—sculpt vast regions of space through their radiation and
supernova explosions. The newly discovered Dragonfish association (pictured) is 32,000 light-years distant and hides behind thick dust in the
constellation Crux, the Southern Cross: If 2.5 million photons of yellow light set out toward us, only one photon would make it to Earth. Fortunately,
infrared photons penetrate the dust more easily. As astronomers in Canada will report in an upcoming issue
of The Astrophysical Journal Letters, the Dragonfish harbors about 400 hot, blue, luminous stars. The stars' extreme ultraviolet radiation
strips electrons from protons, thereby ionizing interstellar hydrogen gas and setting it aglow. But the real action will begin when the stars start
exploding—probably within a few million years—triggering the birth of new stars and further enriching the Milky Way with oxygen, magnesium, and other
elements that terrestrial planets and their inhabitants need.
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Parasite Invasion Caught on Camera
For the first time, the tiny malaria parasite, Plasmodium falciparum, has been caught on camera breaking and entering a red blood cell. High
resolution 3D images reveal that once the three components of the parasite—nucleus (blue), other organelles (red), and the green pore the parasite
brings with it and through which it invades (green)—have attached to the cell, a switch is triggered and the parasite is free to burrow through the
cell's membrane. From this point on, the parasite is unstoppable, multiplying within the cell until it breaks out of its host to invade fresh red blood
cells. The new imaging technique will allow researchers to see the effects of novel drugs on this final stage in the parasite's invasion strategy,
researchers report online on this week in Cell Host & Microbe. They hope that this will help scientists develop better drugs to alleviate the suffering of the 400 million
people who contract malaria each year.
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Hot World Breaks Record
Planetary hells keep getting hotter. Twenty years ago, the hottest known planet was nearby Venus, sizzling at 460°C. Then, planet hunters started finding "hot Jupiters"—giant worlds, hotter than Venus, that orbit close to their stars. Some of these planets were more than 1000°C. Now, in a paper submitted to Monthly Notices of the Royal Astronomical Society, astronomers report a new record breaker: WASP 33 b, circling a white-hot star 380 light-years away in the constellation Andromeda. A gas giant like Jupiter, the planet whips around its star every 29.28 hours (versus 225 days for Venus), periodically blocking some of the starlight, which tipped astronomers off to the world's presence. Then, in late October, they used the William Herschel Telescope in the Canary Islands and detected the planet's near-infrared glow. This revealed the temperature: a whopping 3200°C. That's hundreds of degrees hotter than the previous champ and makes Venus look like Pluto in comparison.
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The Dusty Swirls of the Whirlpool Galaxy
SEATTLE, WASHINGTON—Like dancing fire dragons, two dusty spiral arms swirl around the core of a galaxy in this infrared Hubble picture of M51, the Whirlpool galaxy. The
image, presented here today at the 217th meeting of the American Astronomical Society, was obtained by subtracting known starlight from a photograph
taken by Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS), leaving just the infrared glow of warm dust. The countless small, bright
specks in the photograph are tiny clumps of newborn stars that have never been seen before because their optical light is obscured by the surrounding
dust. Surprisingly, no larger, discrete dust clouds were found in the Whirlpool, which is 37 million light-years from Earth. Such larger clouds were
expected on the basis of optical photographs. Images like this should help astronomers untangle how and where gas and dust in galaxies collapse into
new stars.
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A Trillion-Pixel Image of the Night Sky
SEATTLE, WASHINGTON—If you think your new digital camera produces massive files, think again. Yesterday, at the 217th meeting of the American Astronomical Society here,
astronomers presented the largest color image of the night sky ever made, at over 20 million megabytes. The good news: it's free for all to explore.
The bad news: you won't live long enough to scrutinize all of it. Created by stitching together millions of images made over the past decade, the Sloan
Digital Sky Survey image lets you zoom in on any part of the night sky (galaxy M33 is shown here), and contains half a billion stars and galaxies. The
new Sloan Survey data release also provides additional information on motions and distances of countless stars and galaxies. According to astronomer
Michael Blanton of New York University, it's only a matter of time before you will be able to access the new night sky map through Google Sky, the
celestial counterpart of Google Earth. If you can't wait to explore, check out Sloan's SkyServer, where you
can zoom in on any of the 1.2 trillion pixels.
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Thunderstorms Make Antimatter
SEATTLE, WASHINGTON—Thunderstorms produce beams of antimatter. That's the surprising finding reported here yesterday at the 217th meeting of the American Astronomical
Society. Scientists already knew about flashes of high-energy gamma-rays from Earth, which are associated with large thunderstorms. Every day, about
500 of these terrestrial gamma-ray flashes (TGFs) are produced worldwide by accelerated electrons interacting with air molecules. Now, astrophysicists
working with NASA's Fermi Gamma-ray Space Telescope have found that some of the high-energy gamma-ray photons from TGFs are converted into pairs of
electrons and positrons, the positively charged antiparticles of electrons. Every now and then, the orbiting space telescope is hit by some of these
antimatter particles, which rush through Earth's magnetic field. When the positrons collide with electrons in the atoms that make up the spacecraft,
they annihilate each other, producing gamma-ray photons with a telltale energy in the process. The role of lightning in the production of gamma rays
and antimatter is still unclear, but the new discovery might help physicists better understand the mysterious TGF's.
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Put Up Your Dukes!
In an evolutionary novelty, a flightless prehistoric bird found only in Jamaica used its weighty wing bones to clobber rivals during territorial disputes. Researchers examined several partial skeletons of Xenicibis xympithecus, an extinct wading bird about the size of a large chicken that lived some 10,000 years ago. The bone at the tip of the birds' wings—the "hand" bone—was so thick and curved, it appeared deformed. Xenicibis used its hefty hand bones for battle, swinging them like clubs, the researchers posit. Indeed, two of the fossils—a hand bone and upper arm bone—showed wear and tear consistent with fighting. Other birds use their wings as weapons, too, but none wield their hand bones like clubs. The most likely targets of these powerful swings, the researchers report online today in the Proceedings of the Royal Society B, were other Xenicibis, although the bird may have also used its clublike wings to protect its eggs and young from predators.
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