Posted: Tue, Mar 14, 2006, 6:53 AM ET (1153 GMT)
Scientists analyzing comet dust samples returned by NASA's Stardust mission have found minerals that can only form at high temperatures, challenging existing models of comet formation. Initial work on the samples, collected from the vicinity of comet Wild 2 in 2004 and returned to Earth in January, revealed minerals rich in calcium, aluminum and titanium that can only form at high temperatures. That finding is a challenge to existing models of comet formation, which require comets to form in the cold outer regions of the solar system. Planetary scientists speculate that the minerals may have been ejected from the inner solar system in bipolar jets generated by the early Sun, or they may include minerals from other stars that were in the vicinity of the outer solar system when the comet formed. The discovery was announced Monday at the Lunar and Planetary Science Conference in Houston.
