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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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A Planetary System That Looks Like Home
6 November 2007 (All day)
The first planets discovered outside our solar system were bizarre--huge, blazing hot, and looping wildly about their suns. And there was usually just one planet detectable per star. But today, astronomers described a system that looks more like our own, with numerous planets, one of which could potentially support life. "We now know our own sun and its family of planets is not unusual," astronomer Geoffrey Marcy of the University of California, Berkeley, said at a NASA press briefing.
The discovery comes after 18 years of dogged monitoring of 55 Cancri--a star 41 light-years away--by astronomer Debra Fischer of San Francisco State University, Marcy, and colleagues. They measured the slight wobble of the star as its planets tugged at it through their gravity. The wobble shows up in subtle color shifts as the star moves toward and away from Earth, much as the pitch of a train whistle shifts as a train passes. The researchers had already found four planets orbiting the star, but none were in the so-called habitable zone, where it's not too hot or too cold for life. A 2004 upgrade to the telescope-mounted sensor allowed confirmation of what they had suspected was a fifth planet, one that sits on the inside edge of this coveted zone. It orbits in 260 days (close to a venusian year), has a mass 45 times that of Earth's (between that of Neptune's and Saturn's), and is probably a ball of gas with an icy core similar to Neptune and Uranus.
"The fact they found a fifth planet is pretty remarkable," says astrophysicist Alan Boss of the Carnegie Institution of Washington's Department of Terrestrial Magnetism in Washington, D.C. Four has been the max for extrasolar systems so far, he notes, making the 55 Cancri system "the superheavyweight champ of planetary systems."
Although the fifth planet would need a big, rock moon to harbor life, the large gap between it and the system's outermost planet could well contain Earthlike planets, Marcy noted, possibly in the temperature zone in which life could survive. However, detection of such sister planets must await far more sensitive search techniques.