On February 15, a meteor shook Russia as it entered the Earth's atmosphere above the Urals. Now, scientists believe they know where in the universe it came from.
Using as much data they could lay their hands on — from extensive dash-cam coverage, to CCTV footage, to a lucky observation made by the Meteosat-9 weather satellite — Jorge Zuluaga and Ignacio Ferrin from the University of Antioquia in Medellin, Colombia, pinpointed the faraway pocket of the galaxy that sent a giant destructive space rock our way.
They pieced together all the evidence — location, speed, altitude and so on — to estimate the most likely orbit the rock took around the solar system before our planet got in its way. They explain:
"According to our estimations, the Chelyabinski meteor started to brighten up when it was between 32 and 47 km up in the atmosphere … The velocity of the body predicted by our analysis was between 13 and 19 km/s (relative to the Earth) which encloses the preferred figure of 18 km/s assumed by other researchers."
From that they were able to use complex astronomy software to trace back the rock's path. Turns out the Russian meteor (now meteorite) almost certainly originated from an Apollo-class asteroid: a set of well-known, near-Earth asteroids, of which there are about 5200. In fact, the large Apollos are identified as being a significant risk to our planet — so the Chelyabinsk incident was perhaps a lucky escape. [arXiv via Discovery]