A team of astronomers have tracked down the origin of a meteorite which injured more than 1,000 people in Russia.
The rock smashed into Lake Chebarkul, near the Ural Mountains and the city of Chelyabinsk, smashing windows and causing havoc as it ripped through the sky.
But its passage was also captured in astonishing detail and clarity, largely thanks to the Russian trend to have CCTV cameras installed in cars.
Using this video footage, a team from Colombia have managed to work out where it came from - not only the direction in the sky but also its orbit around the Sun.
Jorge Zuluaga and Ignacio Ferrin said thatthey used relatively basic physics and maths to work out how fast the rock fell, and in which direction.
From there they were able to build a picture of its trajectory in space in an elliptical orbit around the sun, and traced its origin the the Apollo asteroid cluster.
Rocks from that region regularly cross Earth's orbit. Of the 9,700 near-Earth space rocks discovered by astronomers, more than 5,000 originate from this region.
Unfortunately, this likely means that it won't be the last threatening space rock to pass nearby - in fact it's certain than more will strike the Earth relatively soon (in cosmic terms).
The team said:
". In order to account for the uncertainties implicit in the determination of the trajectory of the body in the atmosphere, we use Monte Carlo methods to calculate the most probable orbital parameters.
We use this result to classify the meteoroid among the near Earth asteroid families finding that the parent body belonged to the Apollo asteroids. Although semimajor axis and inclination of the preliminary orbit computed by us are uncertain, the rest of orbital elements are well constrained in this preliminary reconstruction."
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