After eight years of analyzing samples from NASA’s Stardust, a team of scientists may have identified seven microscopic specks of interstellar stardust that just might date back to the beginnings of the solar system. If confirmed, these rare dust motes would mark the first found samples of stardust from outside our solar system and could offer up valuable answers to the origin and evolution of extrasolar dust. The interstellar dust could have been created in a supernova explosion millions of years ago and transformed by eons of exposure to extreme space conditions.
Launched in 1999, NASA’s Stardust spacecraft collected samples of stardust for seven years before returning to Earth in 2006. The Stardust Sample Return Canister was then transported and analyzed at NASA’s Johnson Space Center in Houston, where panels of the spacecraft’s aerogel and aluminum foil dust collectors were scanned and uploaded onto the Internet as movies. Citizen scientists were given access to the footage to search for particle tracks.
A particular group of citizen scientists, volunteers at the University of California, Berkeley who call themselves “Dusters,” proved critical in combing through Stardust’s footage and finding two of the tiny interstellar dust motes, an activity akin to finding needles in a haystack. After the Dusters tag a likely track, Andrew Westphal, the lead author of a Science research report on the topic, and his team of scientists verify the identifications. An additional 100 tracks tagged by the Dusters have yet to be analyzed, however, Westphal says he does not expect to find more than a dozen interstellar dust motes in all.
“These are the most challenging objects we will ever have in the lab for study, and it is a triumph that we have made as much progress in their analysis as we have,” said Michael Zolensky, curator of the Stardust laboratory at Johnson and coauthor of a Science article. Already, scientists say the particles have offered insight into the surprising diversity in the chemical composition and structure of interstellar dust.
Images via NASA