Researchers at UC Berkeley’s Space Sciences Laboratory, with international collaboration and the help of more than 30,000 online volunteers, may have recovered the first particles of stardust from outside Earth’s solar system, according to a paper published Friday.
According to the paper, published in the journal Science, the seven potentially interstellar particles were retrieved from NASA’s Stardust spacecraft, which returned to Earth in 2006. The particles were identified with the help of [email protected], a website that allows citizen scientists to scrutinize images of Stardust’s dust collectors online via a virtual microscope.
“We think it’s the first sample of material from between the stars, the solid material from our galaxy,” said research physicist and senior fellow at the laboratory Andrew Westphal, who co-authored the study. “It’s interesting to us, because this is the stuff that our solar system — the sun, planets and us — are ultimately made of, so it’s about understanding our own origins.”
The particles are very different from each other and do not fit a single “stereotype” as previously thought, according to Zack Gainsforth, a staff scientist at the laboratory and co-author of the study. For example, two of the particles — nicknamed Orion and Hylabrook — have distinctive crystalline structures.
According to Veerle Sterken, a researcher involved in modeling interstellar particles’ paths through the solar system and another co-author of the paper, the project will give scientists a way to study interstellar dust directly rather than relying on measurements from telescopes.
Though the stardust is likely to be interstellar in origin, Westphal said, the only way to confirm that fact is to take measurements of them, which, due to the limits of current technology, he didn’t dare do.
“These particles are so tiny that it would be trivial to lose them if we weren’t super careful,” he said, adding that a trillion of them could fit into a teaspoon.
The stardust was captured using aerogel dust collectors. Aerogel, the least-dense solid known to humanity, is a kind of “glass foam,” according to Gainsforth, and is therefore well suited to preserving the fragile structures of the dust particles.
Westphal said critical to the success of the project was the help of [email protected] participants, whom he said have discovered more than 130 “tracks,” or indentations, in the aerogel, which may indicate the presence of a particle. Without the website, he said, finding those particles would have taken decades.
After eight years, [email protected] is still successful. Westphal, however, said the dust collector has yet to be fully scanned and uploaded, and each scan must be searched for tracts.
“Those who may be interested, please try it out,” he added. “It’s a lot of fun.”