In a new project called Stardust@home, University of California, Berkeley, researchers will invite Internet users to help them search for a few dozen submicroscopic grains of interstellar dust captured by NASA's Stardust spacecraft and due to return to Earth in January 2006.
Though Stardust's main mission was to capture dust from the tail of comet Wild 2 - dust dating from the origins of the solar system some 4.5 billion years ago - it also captured a sprinkling of dust from distant stars, perhaps created in supernova explosions less than 10 million years ago.
"These will be the very first contemporary interstellar dust grains ever brought back to Earth for study," said Andrew Westphal, a UC Berkeley senior fellow and associate director of the campus's Space Sciences Laboratory who developed the technique NASA will use to digitally scan the aerogel in which the interstellar dust grains are embedded. "Stardust is not only the first mission to return samples from a comet, it is the first sample return mission from the galaxy."
"Like SETI@home, which is the world's largest computer, we hope Stardust@home will also be a large computer, though more of a neural network, using brains together to find these grains," said Bryan Mendez of the Center for Science Education at the Space Sciences Laboratory. Mendez and Nahide Craig, assistant research astronomer at the laboratory, plan to create K-12 curricula around the Stardust@home project and to reach out to local astronomy groups to boost participation.
Mendez and Craig will describe their educational outreach program in a poster session on Jan. 10 at the national meeting of the American Astronomical Society in Washington, D.C.
Based on previous measurements of interstellar dust by both the Ulysses and Galileo spacecrafts, Westphal expects to find approximately 45 grains of submicroscopic dust in the collector, a mosaic of tiles of lightweight aerogel forming a disk about 16 inches in diameter - nearly a square foot in area - and half an inch thick. Though those searching for pieces of Wild 2's tail will easily be able to pick out the thousands of cometary dust grains embedded in the front of the detector, finding the 45 or so grains of interstellar dust stuck in the back of the detector won't be so easy.
Thanks to a grant from NASA and assistance from the Planetary Society, however, Westphal and his colleagues at the Space Sciences Laboratory have created a "virtual microscope" that will allow anyone with an Internet connection to scan some of the 1.5 million pictures of the aerogel for tracks left by speeding dust. Each picture will cover an area smaller than a grain of salt.
"Twenty or 30 years ago, we would have hired a small army of microscopists who would be hunched over microscopes focusing up and down through the aerogel looking for the tracks of these dust grains," said Westphal. "Instead, we developed an automated microscope to scan the aerogel and hope to use volunteers we have trained and tested to search for these tracks."
