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Considered an icon of conservation science, researchers at World Wildlife Fund (WWF) headquarters in Washington, D.C.,...
The new atlas, which shows the distribution of important trace metals and other substances, is the first product of...
Early in April, the first of a fleet of environmental monitoring satellites will lift off from Europe's spaceport in...
Since 2000, U.S. government health research agencies have spent almost $1 billion on an effort to churn out thousands...
Magdalena Koziol, a former postdoc at Yale University, was the victim of scientific sabotage. Now, she is suing the...
Antiretroviral drugs can protect people from becoming infected by HIV. But so-called pre-exposure prophylaxis, or PrEP...
Two studies show that eating a diet low in protein and high in carbohydrates is linked to a longer, healthier life, and...
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ScienceShot: Most Comets May Be Solar System Aliens
10 June 2010 3:15 pm
Comet McNaught, shown here in a 2007 Earth flyby, may need a passport when it returns later this month. New research suggests that it and trillions of its cousins were actually born light-years away. Computer simulations reported online today in Science reveal that the Oort cloud—a swarm of comets, including McNaught, that orbit the sun far beyond Pluto—contains too many comets for them to have been generated locally. In fact, the simulation suggests, over 90% of the comets in the Oort cloud probably originated around other stars. Billions of years ago, the researchers explain, our solar system congealed along with many others in relatively close proximity inside a nebula—a vast cloud of dust and gas that acts as sort of a galactic hatchery. As the sun condensed and migrated out of the nebula, it carried the rest of our solar system with it. But its gravity also snagged a huge number of comets from the Oort clouds surrounding its siblings in the process. So welcome back, McNaught, regardless of where you came from.
See more ScienceShots.