Comet dust is surprising scientists

SAN DIEGO, Dec. 14 (UPI) -- A U.S.-led team of scientists says the samples of comet dust returned to Earth early this year suggest some cosmic theories may have to be reconsidered.

The samples were collected by the National Aeronautics and Space Administration's Stardust mission that was launched in 1999. The spacecraft met comet Wild 2 beyond the orbit of Mars in 2004, collected thousands of tiny particles from the comet and returned to Earth last January.

"The analysis of these cometary dust grains proves that the early solar system was a violent place capable of ejecting dust grains out to distances beyond Neptune," said Gerardo Dominguez, a University of California-San Diego physicist.

University of Washington astronomer Donald Brownlee, principal investigator for Stardust, noted the tiny specks of the dust are being examined by more than 150 scientists around the word, utilizing such complex tools as the 2-mile-long Stanford Linear Accelerator.

"We're doing things no one ever imagined we could do, even at the time we launched the mission. We've taken a pinch of comet dust and are learning incredible things," said Brownlee.

The scientists report their initial findings in the current issue of the journal Science.