There is a giant asteroid abroad solar systemand it throws a big rock after Earth.
The evidence for this enigmatic rock comes from a diamond-laden meteor that exploded over Sudan in 2008.
NASA spotted the 9 tons (8,200 kilograms), 13 feet (4 meters) meteor well before the impact on the way to the planet, and researchers arrived in the Sudanese desert to collect an extraordinarily rich surplus. Now a new study of one of the meteorites suggests that the meteor may have broken off from a giant asteroid – one more or less as large as the dwarf planet Ceres, the largest object in the asteroid belt.
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Like about 4.6% of meteorites on Earth, this one – known as Almahata Sitta (AhS) – is made from a material known as carbonaceous chondrite. These black rocks contain organic compounds, as well as a variety of minerals and water.
The mineral composition of these space rocks provides clues as to the “parent asteroid” that gave birth to a given meteor, said researchers in a statement.
“Some of these meteorites are dominated by minerals that provide evidence for exposure to water at low temperatures and pressures,” said co-author Vicky Hamilton, a planetary geologist at the Southwest Research Institute in Boulder, Colorado. “The composition of other meteorites indicates warming in the absence of water.”
The team analyzed a dissimilar 0.0018-ounce (50 mg) sample of AhS under a microscope and found that it had a unique mineral composition.
The meteorite contains an unusual series of minerals that form at intermediate temperatures and pressures (higher than you would find in a typical asteroid, but lower than the inside of a planet). One mineral in particular, amphibole, also requires prolonged exposure to water to develop.
Amphibole is common enough on earth, but it only occurs once in trace amounts in a meteorite known as Allende – the largest carbonaceous chondrite ever dropped in Chihuahua, Mexico, in 1969.
The high amphibole content of AhS suggests that the fragment broke down an older asteroid that had never left meteorites on Earth.
And samples brought back from the asteroids Ryugu and Bennu by the Japanese Hayabusa2 and NASA’s OSIRIS-REx probes are likely to reveal more spatial rock minerals rarely found in meteorites, the researchers wrote in their study.
Perhaps some types of carbonaceous chondrite also did not survive the plunge into the atmosphere, Hamilton said, and that prevents scientists from studying a scent of chondrite that may be more common in space.
“We think there is more carbonaceous chondrite material in the solar system than is suggested by our collection of meteorites,” she said.
The paper was published in the magazine on 21 December Natural Astronomy.
Originally published on Live Science.