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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Comet Revealed as a Giant Dog Bone
4 November 2010 12:40 pm
At about 10 a.m. this morning, the EPOXI spacecraft screamed by the icy nucleus of comet Hartley 2 at 43,000 kilometers per hour. The fifth comet ever imaged so close up, Hartley 2 looks a bit like a dog bone, or a dumbbell, or, more technically, a highly elongated triaxial thingy. The shape of the comet, which is only about a kilometer in size, is reminiscent of Comet Borrelly, first sighted by the Deep Space 1 spacecraft in 2001, only more so. Presumably, Hartley 2 was once two separate bodies that came together. Or, it could have always been a solitary, barely compacted collection of rubble that came close to splitting in two when it spun too fast. Today, the sun's warmth is driving off water vapor, other gases, and dust—especially in bright jets seen streaming off the far end—that have been locked up in the comet since the solar system formed 4.6 billion years ago. This afternoon, team scientists will release processed images and perhaps make some sense of the rough ends and smooth neck between, something never seen before.
See more ScienceShots.