REUTERS/Copyright 2013 EUMETSAT/Handout

Scientists have begun piecing together the characteristics of the meteor that exploded over Russia on the morning of February 15, using data from seismic instruments that track earthquakes and microphones designed to detect sonic booms from nuclear explosions. Unlike the asteroid DA14, which narrowly but predictably missed Earth later that day, the meteor was too small to detect before its contrail appeared in the dawn skies over the Russian city of Chelyabinsk.

Yet even an object too small to detect can produce an impressive amount of destruction. The meteor was 15 meters across (compared with 50 meters for 2012 DA14) and weighed more than 7,000 metric tons when it entered Earth’s atmosphere, says Margaret Campbell-Brown, an astronomer at Western University in London, Ontario. She estimates that it was streaking through the sky at supersonic speeds of about 18 kilometers a second before exploding at an altitude of 15 to 20 kilometers, creating a shock wave that shattered glass in a deafening boom once it reached the surface. Various news sources have reported hundreds of buildings damaged and about 1,200 injuries.

Coincidentally, the largest observed meteor to enter the atmosphere since 1908 arrived just hours before a much larger object passed the planet uneventfully at a distance of about 27,000 kilometers.

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