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Surprise found in comet dust

Odd mineral offers clues to solar system's origins

Researchers have found a new mineral within an interplanetary dust particle. The substance — a manganese silicide named Brownleeite — appears to have come from comet 26P/Grigg-Skjellerup, NASA announced June 12.

Originally seen in 1902, the comet reappears every five years.

In 2002, NASA space scientist Scott Messenger predicted that as they pass, comets shed dust grains that fall into Earth’s upper atmosphere. Using a high-altitude spacecraft, NASA performed periodic dust collections in the stratosphere and gathered 26P/Grigg-Skjellerup’s particles in April 2003.

Studying the sample, the science team began to tease out what mineral made up the individual grains. But a few months ago, researchers saw one substance they hadn’t seen before, says Simon Clemett, a NASA space scientist on the team.

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