Fire and Ice: Scientists Study Comet Particles

Scientists at Johnson Space Center are getting their first up-close look at tiny samples of comet dust that were collected during the seven year "stardust" mission that concluded in January. Here's Houston Public Radio's Jack Williams.

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The primitive materials were collected at the edge of the solar system when the Stardust capsule passed within 150 miles of a comet in January of 2004. Now, scientists are extracting tiny particles from a special gel that both caught and then protected them on the way back to earth. Donald Brownlee is the project's principal investigator at JSC.

"Remarkably enough, we have found fire and ice. We have found samples in the coldest part of the solar system, we found samples that are formed at extremely high temperatures. So the hottest samples in the coldest place."

Using tiny diamond knives, the particles are sliced into sections and then analyzed for composition. Brownlee says scientists have found that the particles are made-up of an array of minerals.

"Among the more exotic things we have found is the titanium nitride, actually rich in vanadium. It has an interesting name, osbornite, nothing to do with Ozzie, but it's still an exotic material. All of these minerals actually form at moderately high to extremely high temperatures. It's quite exciting to find these things at the edge of the solar system."

Scientists are working their way through 132 collection cells and expect to study thousands of particles captured during the comet fly-by. Co-Investigator Michael Zolensky says finding minerals formed in extremely hot conditions in the coldest parts of the solar system raises some new questions.

"It's sort of a big surprise to see such hot materials out even further away where there are even colder materials still. It suggest that if these are really from our own sun, they've been ejected out, ballistically out all the way across the entire solar system and landed out there. That means these materials were basically on a conveyor belt, being shot out and then gradually drifting in, and being shot out again."

The samples from the Stardust mission are kept after they're cut up and studied. Zolensky says the hope is that future scientists will be able find out even more about the origins of the solar system.

"When new questions arise you can pull the samples out and address them again and again. They're really a spur for future development of techniques. We expect these Stardust samples now basically will spur techniques even further and the next generation of sample return missions will benefit from that just as we've benefitted from work on the lunar samples."

You can find out more about the Stardust mission on the sample recovery on our website,

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