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FOR IMMEDIATE RELEASE
April 5, 2002

NASA Spacecraft Finds Comet Has Hot, Dry Surface

Comets are sometimes described as "dirty snowballs," but a close flyby of one by NASA's Deep Space 1 spacecraft last fall detected no frozen water on its surface.

Comet Borrelly and its topographical map (right).
Image Credit: Borrelly image page & Deep Space 1.

Comet Borrelly has plenty of ice beneath its tar-black surface, but any exposed to sunlight has vaporized away, say scientists analyzing data from Deep Space 1, managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"The spectrum suggests that the surface is hot and dry. It is surprising that we saw no traces of water ice," said Dr. Laurence Soderblom of the U.S. Geological Survey's Flagstaff, Ariz., station, lead author of a report on the Borrelly flyby results appearing in the online edition of the journal Science.

"We know the ice is there," he said. "It's just well-hidden. Either the surface has been dried out by solar heating and maturation or perhaps the very dark soot-like material that covers Borrelly's surface masks any trace of surface ice."

(More: Jet Propulsion Laboratory News Source)

Dan