Astronomers have spotted an icy object near Neptune that they say hails from the distant Oort Cloud, the distant reservoir of asteroids that encircles the solar system out beyond the orbit of Pluto.
The object, at least 30 miles wide, is on the return leg of a 22,500-year journey around the sun, astronomers announced today [SPACE.com].
The new object is about 60 miles in diameter. "It's basically a comet, but it never gets close enough to the Sun to develop a long, bright tail of evaporated gas and dust," [lead researcher Andrew] Becker said in a statement [Reuters].
Researchers say the newly discovered voyager, which is currently going by the unromantic name 2006 SQ372, is the first object ever sighted from the inner Oort Cloud, a region that astronomers know very little about. Studying the comet as it makes its way through the solar system could give astronomers new insight into the Oort Cloud's composition, says co-discoverer Nathan Kaib:
“Comets like SQ372 have the potential to tell us what the entire Oort Cloud looks like, which will test theoretical models of the cloud's formation as well as provide clues about the environment that the solar system first formed in” [Science News].
Researchers believe that the cloud's contents once lurked near Jupiter and the other gas giants back in the solar system's distant past, but were knocked away through gravitational encounters with the planets. Researchers found the comet in data gathered by the Sloan Digital Sky Survey that scanned the same stretch of sky in the autumns of 2005, 2006, and 2007; the discovery was announced at an international symposium covering research involving the Sloan Survey.
Other objects from the inner Oort cloud are likely to be found soon, as powerful new survey telescopes are built. "I would expect them to discover thousands of such objects, and with a data set so large, we could do a pretty good job in finding out what the inner Oort cloud looks like," [New Scientist],
Image: A. Becker and the SDSS