Dartmouth researchers examine comet particles
Two Dartmouth researchers are part of the worldwide team that is studying
the comet material collected by NASA's Stardust spacecraft.
Studies about the dust-like particles appeared in the journal Science on Dec. 15 in an issue
highlighting the results from the preliminary examination team. The research
concerns the basic chemical and physical makeup of the comet's particles, which
reveals valuable information about the solar system and how it was made.
Susan Taylor and Chuck Daghlian are studying tiny particles from a comet called
Wild 2. (Photo by Joseph Mehling '69)
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"One of the most exciting results so far is finding high-temperature
minerals in this comet called Wild 2," says Susan Taylor,
one of the authors on the study who is an adjunct professor of earth sciences and a
research physical scientist at the U.S. Army Corps of Engineers Cold
Regions Research and Engineering Laboratory (CRREL). "Because Wild 2
is thought to have formed beyond the orbit of Pluto, it was expected to have
only low-temperatures minerals. Finding the high-temperature minerals like
pyroxenes and olivines suggests that there was more mixing of matter in the
early solar system, when the sun and planets were forming, than previously
thought."
Launched in 1999, Stardust returned to Earth earlier this year. It flew in
the wake of the comet Wild 2. The tiny samples were captured using a material
called aerogel, also called solid smoke, which slowed down, cushioned, and
stored the material from the comet's tail. These comet particles hit the
aerogel at speeds of six kilometers per second (more than 11,000 miles per
hour).
"We had the opportunity to image and chemically analyze three
particles," says Charles Daghlian, another member of the team and the
director of Dartmouth's Electron
Microscope Facility. "The largest particle was 10 microns [an average
human hair is about 100 microns in diameter], and it proved to be very rich in
carbon, one of the basic building blocks of life."
Daghlian and Taylor also worked with student Emily Koepsell '09. As part of
Dartmouth's Women in Science
Project (WISP), Koepsell helped analyze the particles from Wild 2 using the
scanning electron microscope, a skill she learned as a WISP intern.
By SUSAN KNAPP
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