A First Look at a Comet's Dust.

The article reports on scientists from National Aeronautics and Space Administration (NASA) testing theories about the composition and formation of the early solar system. The success of NASA's Stardust mission, which returned material from comet Wild-2, is helping these scientists for their investigation. So far, scientists have identified glassy and crystalline compounds, including iron sulfides. Although sulfides were not unexpected, there had been no spectral evidence that comets contain sulfur. Mission scientists have also found hints of organic matter and so-called glass embedded with metal and sulfides. Comets originated at the periphery of the rotating cloud of gas and dust that formed the solar system and likely retain pristine material from that time.