JPL is coming to terms with comets not all being cold from the start after the StarDust mission returned Forsterite (Peridot) along with all of the ice and dust.
“Remarkably enough, we have found fire and ice,” said Donald Brownlee, Stardust principal investigator and professor of astronomy at the University of Washington in Seattle. The returned samples show high-temperature materials from the coldest part of our solar system.
This looks like more serious overturning of “basic” solar system principles, and may yet point out more alternatives to the obsolete drift-forever and Oort-cloud-only comet models.
This progress will largely be painful for those individuals betting their careers on one or the other theory, but it really seriously invites genuine new exploration and the raising of novel practical theories for testing and experiment.
Comets, they said, may not be as simple as the clouds of ice, dust and gases they were thought to comprise. They may be diverse with complex and varied histories.