Friday, December 15, 2006

News from the Stardust Spacecraft

In this week's issue of Science magazine, the team behind NASA's Stardust mission reports their initial findings. Some of these have made the news in the last couple of days. Since the results are interesting, and since I have spoken with mission head Don Brownlee on several occassions, I thought I would blog a bit about that news today.

Stardust is a spacecraft that went through the cloud of dust around Comet Wild 2 ("Wild" is pronounced "Vilt") a few years ago. The spacecraft used a collector to pick up the dust and bring it back to Earth.

Comets are interesting to study because we know they formed in the outer parts of the solar system. Comets are full of ices that melt when close to the sun, so the comets had to form far out. We therefore expected to find that the comet was full of pristine material, "star dust" created by other stars that happened to be in the area when the comet formed.

But Stardust has found that the comet is not pristine. Yes, it has a lot of star dust, but it also has things that formed very close to the sun -- glasses and compounds that had to be made in a hot area. Some of these compounds are identical to the volcanic sands on the Big Island of Hawaii! And there is too much of this material to have been captured by the comet on previous trips past the sun.

We think that these findings show that the very early Solar System was a turbulent, violent place. Plumes of material from near the proto-sun were pushed out beyond the orbit of Pluto by processes we don't understand. And that took a lot of energy!

As is often the case, these findings raise more questions than answers. But it gives us plenty of new research to work on, so I won't complain!

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