New type of mineral discovered from comet
Friday, 13 Jun 2008 09:13
Earth receives about 40,000 tonnes of dust particles from space each year
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Scientists say they have discovered a brand new type of mineral that they think entered the Earth's atmosphere from a comet.
The mineral, named Brownleeite after the astronomy professor Donald Brownlee, becomes the 4,325th known to man.
It was discovered by an international team of researchers and scientists within an interplanetary dust particle (IDP) that appears to have come from the comet named 26P/Grigg-Skjellerup.
The comet originally was discovered in 1902 and reappears every five years.
Scott Messenger from Nasa's Johnson Space Centre triggered the mineral discovery after predicting that the comet was a source of dust grains that could be captured in the Earth's stratosphere at a specific time of the year.
After a high-altitude aircraft was used to collect the dust, the team discovered the new mineral within one of the particles.
The Brownleeite was surrounded by multiple layers of other minerals that also have been reported only in extraterrestrial rocks.
"When I saw this mineral for the first time, I immediately knew this was something no one had seen before," said space scientist Keiko Nakamura-Messenger.
"But it took several more months to obtain conclusive data because these mineral grains were only 1/10,000th of an inch in size."
The Earth receives about 40,000 tonnes of dust particles from space each year, originating mostly from disintegrating comets and asteroid collisions.
Scientists are keen to study this dust because it is made of the original building blocks of the solar system.