On January 15, 2006, NASA's Stardust spacecraft returned to Earth to drop off a capsule that contained the first samples of a comet and interstellar dust.

Two weeks earlier, Stardust visited the comet Wild 2 and collected some dust from its coma. After spending seven years in space, the 100-lb. capsule touched down in Utah. Scientists analyzed the dust grains and discovered some organic compounds, like nitrogen and hydrocarbons. They also found material that was older than the sun. Just as they suspected, the particles collected by the Stardust mission turned out to be leftovers of the ancient building blocks of our solar system.