"Fire And Ice" Among Cometary Samples

Scientists continue to be amazed by the wealth and type of information brought back to Earth by NASA's Stardust probe back in January. In fact, the first results have turned up a major surprise: tiny fragments of minerals (a sample is shown at right) formed under high temperatures, rather than just the simple cosmic dust fragments scientists were expecting.

"Remarkably enough, we have found fire and ice," principal investigator Donald Brownlee, of the University of Washington, said at a news conference Monday. "We are finding these high-temperature minerals in materials from the coldest place in the solar system."

The Los Angeles Times reports those minerals were formed at temperatures believed to be present only in nebulae surrounding primitive stars -- indicating the minerals brought back by Stardust were either created during the formation of the sun, or created by other stars, drifting across interstellar space into our galaxy.

Scientists also found such diverse minerals as olivine, a big component of the green sand found on some Hawaiian beaches, in the particles collected from the tail of the Wild 2 comet.

The findings tell scientists that comets aren't merely lifeless clumps of interstellar ice and dust -- but instead, have far more varied, interesting histories.

Brownlee said researchers will ultimately be able to pinpoint the origin of the minerals by looking at their isotopic composition -- but that may have to wait awhile, as only six of the 132 individual cubes of "aerogel" used to trap the cometary particles have been examined.

Meaning... there's a lot of science still left to be revealed, as more than 150 scientists continue to examine ultra-thin fragments of aerogel -- sliced only a few hundred atoms wide -- in labs around the world.

Most of the particles "are much, much smaller than a human hair," said co-investigator Michael Zolensky of the Johnson Space Center in Houston, where the particles are being stored and processed.

What's more -- scientists haven't even gotten to particles of interstellar dust collected by aerogel on the opposite side of the probe, which was open as the craft sped towards its rendezvous with Wild 2 (above).

"There are so few of them and they are so tiny that we have little idea how to study them today," Zolensky said.

FMI: www.nasa.gov