Dartmouth researchers study comet dust

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(Host) Two Dartmouth researchers are among the first to study material collected from the tail of a comet.

As VPR’s Steve Zind reports, what they and other scientists discover could tell us more about how the earth was created.

(Zind) The black and white speck magnified five thousand times under an electron microscope in a Dartmouth lab looks pretty ordinary.

(Daghlian) “It looks like a pile of dirt. It’s not a very dramatic image.”

(Zind) In reality, though, this speck of dust represents a unique opportunity for Dartmouth researcher Charles Daghlian and Susan Taylor of the Army Corps of Engineers Cold Regions Laboratory.

(Taylor) “These are the first comet samples that we know of, so just to find out what this cometary material looks like is very exciting.”

(Zind) The samples total a few thousand particles, each a fraction of a hair’s width in diameter. They were collected by the Stardust spacecraft which flew two billion miles to rendezvous with a comet called Wild 2 and then returned to earth.

The specks of comet dust it collected represent the most pristine material scientists have ever examined. It hasn’t been subjected to the violent forces that created the planets, so it’s been unchanged for billions of years – so it offers a glimpse back through time.

By studying the samples scientists hope to learn more about how the solar system was formed. Their research will also give them insights into the makeup of comets. Taylor says photographs taken by the Stardust helped dispel the notion that comets are simply flying piles of loose rubble.

(Taylor) ” and you can tell that from looking at the features on the surface that show these big cliffs and these pinnacles and these things that actually have quite a lot of structure to it. That’s the wonderful thing about science – is you think that you’ve got a pretty good bead on it then you actually go and look at it and its always got surprises.”

(Zind) Scientists know from past research that comets contain the building blocks of life: water, carbon and, amino acids. As they collided with planets, they may have helped distribute those key ingredients through the solar system, where on one planet, conditions were ideal for life to develop. In that sense says Charles Daghlian, Joni Mitchell was right when she sang, “we are stardust”.

(Daghlian) “To the extent that these comets represent the primordial material from which the planets formed, yes we are. We’re made up of the same materials that are in the planet and ultimately that came from comets and stardust, then, yes, we are stardust.”

(Zind) The Dartmouth researchers are part of a worldwide effort to study the material collected from the Wild 2 comet.

The first findings will be published later this year, but Daghlian says it will take many years to discover all there is to learn from the comet dust.

For Vermont Public Radio, I’m Steve Zind.

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