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Stardust took this photo as it approched within 147 miles of the comet Wild 2 (pronounced "vilt two") on Jan. 2, 2004. The comet is named after its discoverer, Paul Wild.
When it passed through the tail of Wild 2, Stardust's collector, filled with aerogel, acted like a catcher's mitt as it grabbed samples. At the time of Stardust's launch, on Feb. 7, 1999, NASA claimed that aerogel was the lightest man-made material on Earth.
aerogelScientists hope that the aerogel, which is 95 percent air, has captured materials that will reveal information from the earliest history of the solar system. The chemical and physical information from the samples could present a record of the formation of planets and the materials from which they were made.
In an experiment using a special air gun, particles are shot into aerogel at high velocities to simulate the collection of samples from Wild 2's tail.