Over the weekend, scientists learned more about the meteor that struck the Chelyabinsk region of Russia on 15 February. Ria Novosti is reporting that scientists from Urals State University in Ekaterinburg have made an expedition to Lake Chebarkul, where meteor fragments reportedly fell.
On the basis of 53 samples between 0.5–1 centimetre in diameter, the researchers determined that the meteor was an ordinary chondrite containing olivine, sulfite and about 10% iron. The material is consistent with a stony meteoroid from the asteroid belt.
While Russian researchers get their hands on the tiny meteorites that remain, other researchers have been sifting through the data picked up by a network of infrasound stations that are designed to listen for atomic weapons tests. As many as 17 stations, including one as far way as Antarctica, have picked up the reverberation of the meteor in the atmosphere. The Comprehensive Nuclear-test-ban Treaty Organization, which runs the network, is now calling the explosion the largest ever seen by their system.
NASA has fresh figures on the meteor, based on infrasound data. According to an updated release from the Jet Propulsion Laboratory in Pasadena, California, the meteor was 17 metres across and weighed 10,000 tonnes. The explosive energy was nearly 500 kilotonnes.