Astronomers say they've tracked down the source of the meteorite that burned up over Russia earlier this month, injuring more than 1,000 people.
The team, from the University of Antioquia in Colombia, used amateur footage of the event to trace its trajectory back through the Earth's atmosphere and work out its orbit around the sun.
Because so many Russians have car dashboard cams, there's an unprecedented amount of video of the event, complete with precise time stamps. Combining this with other sources, particularly one camera in Revolution Square in the city of Chelyabinsk, the team was able to use simple trigonometry to calculate the meteorite's trajectory.
The results suggest that the meteorite originated in the Apollo asteroids, which can cross Earth's orbit, and account for more than half the near-Earth objects discovered so far.m Meanwhile, the American Meteoritic Society has published a calculation of the object's trajectory, and come up with broadly similar results.
Since the explosion, meteorite hunters have been out in force - although the bulk of any debris appears to have fallen in Lake Chebarkul.
"The mass of the largest fragment, which landed in the lake Chebarkul,
was estimated to be 200-500 kg. One or two meteorites of the mass of several tens of kg can be expected not far from the village Travniki," say scientists from the Czech Astronomical Institute of the Academy of Sciences.
"One piece of mass approximately 1 kg may have landed to the northwest of Shchapino. Numerous small fragments can be expected in the wide band located about 5 km south of the trajectory, mostly between longitudes 60.9 and 61.35 degrees."
Several pieces of rock claimed to be meteorite fragments are up for sale online, with prices of up to $20,000.