Washington, September 18 : In a very rare finding, scientists have discovered an unusual kind of meteorite in the Western Australian desert and have uncovered that it came from the innermost main asteroid belt between Mars and Jupiter.
Meteorites are the only surviving physical record of the formation of our Solar System.
However, information about where individual meteorites originated, and how they were moving around the Solar System prior to falling to Earth, is available for only a dozen of around 1100 documented meteorite falls over the past two hundred years.
According to Dr Phil Bland from the Department of Earth Science and Engineering at Imperial College London, the lead author of the study, “We are incredibly excited about our new finding. Meteorites are the most analysed rocks on Earth, but it’s really rare for us to be able to tell where they came from.”
The new meteorite, which is about the size of cricket ball, is the first to be retrieved since researchers from Imperial College London, Ondrejov Observatory in the Czech Republic, and the Western Australian Museum, set up a trial network of cameras in the Nullarbor Desert in Western Australia in 2006.
The researchers aim to use these cameras to find new meteorites, and work out where in the Solar System they came from, by tracking the fireballs that they form in the sky.
The new meteorite was found on the first day of searching using the new network, by the first search expedition, within 100m of the predicted site of the fall.
The meteorite appears to have been following an unusual orbit, or path around the Sun, prior to falling to Earth in July 2007, according to the researchers’ calculations.
The team believes that it started out as part of an asteroid in the innermost main asteroid belt between Mars and Jupiter.
It then gradually evolved into an orbit around the Sun that was very similar to Earth’s.
The new meteorite is also unusual because it is composed of a rare type of basaltic igneous rock.
According to the researchers, its composition, together with the data about where the meteorite comes from, fits with a recent theory about how the building blocks for the terrestrial planets were formed.
This theory suggests that the igneous parent asteroids for meteorites like today’s formed deep in the inner Solar System, before being scattered out into the main asteroid belt.
Asteroids are widely believed to be the building blocks for planets like the Earth, so the new finding provides another clue about the origins of the Solar System.
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