comets

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NASA Finds New Type Of Comet Dust Mineral
ScienceDaily (Jun. 17, 2008) — NASA researchers and scientists from the United States, Germany and Japan have found a new mineral in material that likely came from a comet.

The mineral, a manganese silicide named Brownleeite, was discovered within an interplanetary dust particle, or IDP, that appears to have originated from comet 26P/Grigg-Skjellerup. The comet originally was discovered in 1902 and reappears every 5 years. The team that made the discovery is headed by Keiko Nakamura-Messenger, a space scientist at NASA's Johnson Space Center in Houston.

"When I saw this mineral for the first time, I immediately knew this was something no one had seen before," said Nakamura-Messenger. "But it took several more months to obtain conclusive data because these mineral grains were only 1/10,000 of an inch in size."

A new method of collecting IDPs was suggested by Scott Messenger, another Johnson space scientist. He predicted comet 26P/Grigg-Skjellerup was a source of dust grains that could be captured in Earth's stratosphere at a specific time of the year.