Near-Earth asteroid is actually a comet - Indian Express

PTI : Washington, Thu Sep 12 2013, 14:33 hrs The third largest near-Earth object - believed for 30 years to be an asteroid - is actually a comet, a new study has found. Called 3552 Don Quixote, the body is one of the near-Earth objects - mostly rocky bodies, or asteroids, that orbit the Sun in the vicinity of Earth. About 5 per cent of near-Earth objects are thought to be "dead" comets that have shed all the water and carbon dioxide in the form of ice that give them their coma - a cloud surrounding the comet nucleus - and tail. The discovery could hold implications for the origin of water on Earth, researchers said. An international team including Joshua Emery, from the University of Tennessee, found that Don Quixote is an active comet, thus likely containing water ice and not just rocks. "Don Quixote has always been recognised as an oddball," said Emery. "Its orbit brings it close to Earth, but also takes it way out past Jupiter. Such a vast orbit is similar to a comet's, not an asteroid's, which tend to be more circular - so people thought it was one that had shed all its ice deposits," Emery said. Using the NASA's Spitzer Space Telescope, the team led by Michael Mommert of Northern Arizona University re-examined images of Don Quixote from 2009 when it was in the part of its orbit closest to the Sun, and found it had a coma and a faint tail. Emery also reexamined images from 2004, when it was at its farthest distance from the Sun, and determined that the surface is composed of silicate dust, which is similar to comet dust. He also determined that Don Quixote did not have a coma or tail at this distance, which is common for comets because they need the Sun's radiation to form the coma and the sun's charged particles to form the tail. ... contd. ALSO READ Yahoo CEO Marissa Mayer fears defying NSA on data could mean prison Apple Inc. is one of my best right now: Icahn Dyson launches legal action against Samsung Electronics Federal Trade Commission to scrutinize new Facebook facial recognition feature Please read our terms of use before posting comments TERMS OF USE: The views, opinions and comments posted are your, and are not endorsed by this website. You shall be solely responsible for the comment posted here. The website reserves the right to delete, reject, or otherwise remove any views, opinions and comments posted or part thereof. You shall ensure that the comment is not inflammatory, abusive, derogatory, defamatory &/or obscene, or contain pornographic matter and/or does not constitute hate mail, or violate privacy of any person (s) or breach confidentiality or otherwise is illegal, immoral or contrary to public policy. Nor should it contain anything infringing copyright &/or intellectual property rights of any person(s). via Science - Google News http://news.google.com/news/url?sa=t&fd=R&usg=AFQjCNHim-NJqRa9b1Forn9k7Q7eEeXE2w&url=http://www.indianexpress.com/news/nearearth-asteroid-is-actually-a-comet/1168259/

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