COMET TEMPEL-1 MAY HAVE FORMED IN GIANT PLANETS REGION

Comet Tempel-1 may have been born in the region of the solar system occupied by Uranus and Neptune today, according to one possibility from an analysis of the comet's debris blasted into space by NASA's Deep Impact mission. If correct, the observation supports a wild scenario for the solar system's youth, where the planets Uranus and Neptune may have traded places and scattered comets to deep space.

"Our observation is a definitive investigation revealing the composition of comet Tempel-1," said Dr. Michael Mumma of NASA's Goddard Space Flight Center, Greenbelt, Md. Mumma and his team used the powerful Keck telescope on top of Mauna Kea, Hawaii, to analyze in great detail light emitted by Tempel-1 gas ejected by the impact. Because each type of atom and molecule emits light at unique colors (frequencies), the team was able to determine the comet's chemical composition by separating its light into its component colors with an instrument called a spectrometer. Mumma is lead author of a paper on this research that appeared in Science on September 15.

http://www.nasa.gov/mission_pages/deepimpact/media/deepimpact-090905.html