Updated 11:45 am: While the world waits for an asteroid large enough to destroy a city to graze the orbits of our television satellites, citizens of Central Russia were greeted early Friday morning by a more mortality-shaking kind of astronomical event: a giant meteorite exploding across the atmosphere in a spectacular fireball, brighter than the still-rising sun, blowing out windows and injuring as many as a thousand people.
‘‘A serious meteor fell,’’ Sergey Galitskiy, the billionaire CEO of OAO Magnit, Russia’s biggest food retailer, wrote on Twitter. ‘‘At our hypermarket in Emanzhelinsk, windows were blown out, the roof shook, there was a strong shock wave.’’
The Russian Ministry of Sciences estimated that the meteor weighed about 10 tons, or the weight of eight cars, as it entered the atmosphere and began breaking up.
The object, which was thought by some at first to be a military fighter jet crash or a missile explosion or something else completely, wasn't related to the giant asteroid that is set to pass Earth later on Friday, also known as 2012 DA14: it was simply a stunning coincidence. Technically, the object was a meteorite, a piece of rock as large as a boulder that causes a visible trace as it enters the Earth's atmosphere. That trace is called a meteor, and the pieces that make it to Earth are known as meteorites.
According to state-sponsored radio station The Voice of Russia, the meteor was allegedly intercepted by a missile salvo fired from an air defense facility at Urzhumka village near the city of Chelyabinsk, 900 miles east of Moscow, "at an altitude of 20 kilometers." "Witnesses reported a sudden change in atmospheric pressure upon the impact that made their ears pop. The space object hit the ground with a tremendous crash that resembled thunder and earthquake, damaging houses in Chelyabinsk and cutting off communications, witnesses say. Residents of Emanzhilinsk, a town 50 kilometers away from Chelyabinsk, said they saw an object high in the sky that suddenly burst into flames, broke apart and fell to Earth."
In videos posted online, many of them from the dashcams that are nearly ubiquitous throughout Russia, the bangs are from the sonic boom of the meteor as it explodes and disintegrates across the lower atmosphere, as Phil Plait points out. He also noted that the meteor's train, the term for a meteor trail, appears to be split, indicating a significant break-up as it hit the atmosphere.
"Preliminary indications are that it was a meteorite rain," an emergency official told RIA-Novosti. "We have information about a blast at 10,000-metre altitude. It is being verified." Residents of the Chelyabinsk and Sverdlovsk regions reported witnessing burning objects in the sky. Mobile phones were working intermittently but that may likely have been due to overtaxed infrastructure. Officials said that the meteorite shower did not effect communciations and did not cause an increase in radiation levels.
But it did cause injuries to more than 100 people, mostly from broken glass, Vadim Kolesnik, a ministry official, told Interfax, though none were very serious. Amidst the apparent panic of residents, Russia’s public health chief Gennady Onishchenko closed schools in the Chelyabinsk region. After the meteor lit up the sky with a light brighter than the sun, the sounds of car alarms and breaking windows could be heard throughout the area. Residents were reportedly using plastic wrap to replace broken windows, as temperatures in Chelyabinsk fell to -14°C by evening.
A classroom in the city of Chelyabinsk, after the shockwave (via chelyabinsk.ru)
The meteor disintegrated over the Ural mountains. (Map via Sydney Morning Herald)
"What happened over the Urals region was not a meteor shower, as was reported earlier," Emergency Situations Ministry spokesperson Yelena Smirnykh told Interfax. "It was a meteorite, which burned up as it passed through the lower layers of the Earth atmosphere. However, it triggered an impact wave, which smashed windows in several houses in the region," she said. The trace from a falling object could be seen in Yekaterinburg, some 200 kilometers (125 miles) southeast of Chelyabinsk, a witness told Reuters. (More photos and videos of the meteor are here.)
While Earth is currently thought to be safe from Earth-ending asteroids, NASA and others struggle to keep track of large Near Earth Objects (and the US space agency is even training to land on one). A dangerous NEO doesn't need to reach the surface to make an impact. In 1908 a meteor estimated to be around 50 meters across exploded above Tunguska, Siberia in remote Russia. The blast, known as the Tunguska Event, had the strength of a 15 megaton nuclear bomb (the light from the explosion was seen in London) and flattened trees for over 830 square miles.
Russian officials have said that meteorite pieces from this event were not expected to land on Earth. But that isn't likely to stop the meteorite hunters from looking: the space-rock industry is already booming in Central Russia, where, 10,000 years ago a shower of iron is said to have spread minerals--some of the most primitive materials in the solar system--across the region. The government doesn't mind the business, reported Russia Today in 2011: it levies a meteorite tax on sales of these rocks, which are thought to be part of the building blocks of planets.