The asteroid that hit Earth last year and exploded over Chelyabinsk, Russia, had a prior crash record.
Fragments of the asteroid recovered after the powerful Feb. 15, 2013, airburst show it contained an unusual form of the mineral jadeite embedded in glassy structures known as shock veins.
Shock veins typically form when the parent body of a meteor or asteroid collides with a larger object in space. Heat and pressure from the impact cause rock to melt. It later reforms bearing vein-shaped patterns.
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"Impact-induced jadeite has been found from other shocked meteorites. However, a unique point of the Chelyabinsk jadeite is that it seems to have crystallized from melt. To my knowledge, previously reported jadeite in other meteorites is considered to have formed (by solid-state reaction) without melting," graduate student Shin Ozawa, with Japan's Tohoku University, wrote in an email to Discovery News.
The evidence indicates the 65-foot wide asteroid which blasted apart over Chelyabinsk - damaging buildings, shattering windows and leaving more than 1,000 people injured by flying debris - had a massive run-in with a much larger object about 500 feet in diameter.
Analysis of material in the Chelyabinsk meteorites suggests the crash happened some 290 million years ago. Forces from the impact may have set the Chelyabinsk asteroid on its collision course with Earth.
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The research is expected to help scientists assess future risks to Earth from nearby asteroids – and offer a possible solution.
"Impacts with other asteroids can be a possible mechanism to change" a potentially threatening near-Earth object (NEO) by shifting its orbit," Ozawa wrote.
"It is important to know the properties and formation histories of NEOs. In this context, Chelyabinsk meteorite is a unique sample – fragments of an NEO actually hit the Earth and its trajectory was well-recorded," Ozawa added.
The research appears in this week's Scientific Reports.