November 08, 2024
Column

Stardust package a time capsule

If it’s true that the best things in life often come in small packages, space scientists might just have received a 100-pound gold mine of information about the very beginnings of our universe.

This gift from deep space, a sample container jettisoned from the Stardust explorer after a journey of seven years and almost 3 billion miles, landed by parachute on a remote stretch of the Utah desert on Sunday and straight into the hands of a most appreciative audience.

“Inside this thing is our treasure, our sample of the edge of the solar system that truly contains stardust,” said Donald Brownlee of the University of Washington, the NASA mission’s principal investigator. “We visited a comet, grabbed a piece of it, and it landed here this morning.”

The source of all this elation, which will be shipped this week to a laboratory at the Johnson Space Center in Houston, is about a million samples of comet and interstellar dust, most of them less than one-tenth the width of a human hair.

Scientists believe these grains from the comet Wild 2, near Jupiter, to be the pristine remains of the birth of the solar system about 4.6 billion years ago.

“Very cool stuff,” remarked University of Maine astronomy professor and author Neil Comins when I called him Monday for a crash course in comets and the secrets that may lie within their icy hearts.

Comins said space material regularly falls to Earth in the form of meteorites.

Sometimes what scientists find inside these chunks of rock and metal might arguably have originated on Mars, or conceivably even be a new form of life. The problem with the material gathered previously, however, is that all of it has been contaminated by Earth’s atmosphere before scientists have had a chance to examine it.

“So whether the stuff is a life form or came from Mars is always open to question,” Comins explained.

What makes this most recently collected material so exciting and potentially revealing, he said, is its pristine condition.

“This stuff is different because it was collected in space, and sealed in a capsule that was carefully prepared so as not to contaminate its contents,” Comins said. “If the technology was correct, it would have had no interaction with the Earth’s atmosphere.”

And that, he said, could allow scientists to gain a better understanding of the composition of the virgin solar system and thereby a clearer picture of how much the chemical composition of Earth might have changed over time through weathering and atmospheric effect.

“The information from this untouched material will give us a way to refine the models that we use to explain the evolution of the universe and of life itself,” Comins said.

By examining the molecular makeup of the water ice contained in the comet sample and comparing it to seawater, he said, scientists might also be able to determine whether comets contributed significantly to the amount of water in our oceans.

“With this material we can get a snapshot of the state of our solar system of 4.6 billion years ago,” said Comins. “Just as it’s exciting to open a time capsule from a world’s fair or expo of the 1800s to learn how things have changed, this is a time capsule that will help us see where we started from.”


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