A powerful blast rocked the Russian region of Ural Mountains near Chelyabinsk city early Friday morning on February 15th, 2013 at ~ 9:20 AM local time. Most likely it was a bolide (an exploding fireball) event caused by the a small asteroid entering the Earth’s atmosphere. The explosion was centered in the Chelyabinsk region, which is about 1,500 kilometers east from Moscow. This dramatic event was witnessed not only in Chelyabinsk, but in Yekaterinburg, 200km to the north, in Kazakhstan, to the south, and also in my mother’s native town Kopeisk (BBC news).
(Terminology: A bolide is an extraterrestrial body ranging in size from 1 to 10 km across that hits Earth at velocities faster than a speeding bullet. Meteors are pieces of space rock, which enter the Earth’s atmosphere. Many are burned up by the heat in the upper atmosphere. Those that survive and strike the Earth are called meteorites.)
According to the Russian Academy of Sciences the meteor estimated weight was about 10 tons and it entered the atmosphere at the speed of ~ 54,000 km/h. When the meteorite hits the Earth’s atmosphere at that speed it is like hitting the wall. That releases a huge amount of energy, which is comparable with the huge bomb explosion. The meteor shattered in the upper atmosphere about 30-50 kilometer above ground, creating the strong sound waves and showering the region with smaller debris that caused damage over a wide area. It released the energy of several kilotons above the Chelyabinsk region and broke about 1 million square feet of glass, according to the city official’s estimate.
As a result of the shock waves caused by the blast, ~ 270 buildings in Cheliabinsk have sustained damage and ~ 1000 people reported to hospitals seeking for treatment said Vladimir Stepanov, of the National Center for Emergency Situations at the Russian Interior Ministry. Hospitals, kindergartens and schools are among those affected. As RIA Novosti reported, about 20,000 emergency response workers have been mobilized.
Thanks’ to smart phones and dashboard cameras so popular in Russia, the event was widely captured on amateur video. Some videos showed a bright object speeding across the morning sky, leaving a thick white contrail and an intense flash.
A large meteor fragment was seen landed in a lake outside of Chebarkul, a small town in Chelyabinsk region (BBC Russian).
It is early to tell anything about the meteorite size and composition. We could only provide estimation. As Don Yeomans, head of NASA’s Near-Earth Object Program, told SPACE.com -“If the reports of ground damage can be verified, it might suggest an object whose original size was several meters in extent before entering the atmosphere, fragmenting and exploding due to the unequal pressure on the leading side vs. the trailing side.”
Other bolide explosions over Siberia in the past 100 years
Such meteor strikes are rare and luckily happen in uninhabited areas where they don’t cause damages and injuries to humans. A similar one – Tunguska meteorite – hit Siberia in 1908 (~ 100 years ago) and devastated an area of more than 2,000 sq km.
On 26 February, 1984, a huge Chulym bolide exploded above the Chulym river, Siberia (57.7N; 85.1E)
The last even on the similar scale – Vitim event or Bodaybo event – occurred in 2002. It is believed to be an impact by a bolide in the Vitim River basin. The event occurred near the town of Bodaybo in, Siberia, on September 25, 2002 at approximately 10:00 p.m. It was also detected by a US military missile-defense satellite.
Asteroid 2012 DA14
Interestingly enough, this collision took place as the world waited for February 15th, close pass of asteroid 2012 DA14. According to both the European Space Agency and NASA, no link between the two events is thought possible, but we will see.
For the information on how to watch asteroid 2012 DA14 online, refer to Alan Boyle posting (Science Editor, NBC News)