A meteor streaked through the sky and exploded Friday over Russia's Ural Mountains with the power of 20 atomic bombs, its sonic blasts shattering countless windows and injuring about 1,100 people.
While NASA estimated the meteor was only about the size of a bus and weighed about 7,000 tonnes, the fireball it produced was dramatic. Video shot by startled residents of the city of Chelyabinsk showed its streaming contrails arcing toward the horizon just after sunrise, looking like something from a world-ending science-fiction movie.
The largest recorded meteor strike in more than a century came hours before a 130,000-tonne asteroid passed within about 28,000 kilometres of Earth. The European Space Agency said its experts had determined there was no connection between the asteroid and the Russian meteor — just cosmic coincidence.
The spectacle deeply frightened many Russians, with some elderly women declaring that the world was coming to an end. Many of the injured were cut by flying glass as they flocked to windows to see what the source was for such an intense flash of light.
The meteor entered the Earth's atmosphere at a hypersonic speed of at least 54,000 km/h and shattered about 30 to 50 kilometres above the ground, the Russian Academy of Sciences said in a statement.
It released the energy of 300 to 500 kilotons above the Chelyabinsk region, the academy said.
NASA scientists have also determined that the Russia meteor is not related to 2012 DA14.
Amateur video broadcast on Russian television showed an object speeding across the sky about 9:20 a.m. local time, just after sunrise, leaving a thick white contrail and an intense flash.
"There was panic. People had no idea what was happening. Everyone was going around to people's houses to check if they were OK," said Sergey Hametov, a resident of Chelyabinsk, a city of 1 million about 1,500 kilometres east of Moscow.
"We saw a big burst of light, then went outside to see what it was and we heard a really loud thundering sound," he told The Associated Press by telephone.
Saskatoon native Michael Garnett, a goaltender for Traktor Chelyabinsk in the Kontinental Hockey League, told CBC News he was terrified by the noise, which was so loud he was convinced something had happened right next to his building.
"I thought for sure there was an explosion, and then I thought it might have been a natural gas leak or it could have been a bomb or a missile or a plane crash," he said.
'Really horrible sound'
Another Chelyabinsk resident, Alexander Yakovets, told CBC News he was woken in his eighth-floor apartment by a "really horrible sound" that he first thought might have been a terrorist attack or a military exercise.
He said he saw a very bright light and heard multiple explosions.
"For a couple of minutes, I thought [the building] was going to fall down," he said.
The explosions broke an estimated 100,000 square metres of glass, city officials said.
The Interior Ministry said about 1,100 people sought medical care after the shock wave and 48 were hospitalized. Most of the injuries were caused by flying glass, officials said.
Emergency Situations Ministry spokesman Vladimir Purgin said many of the injured were cut as they flocked to windows to see what caused the intense flash of light, which momentarily was brighter than the sun.
NASA scientists estimated the meteor unleashed a force 20 times more powerful than the Hiroshima bomb, although the space rock exploded at a much higher altitude. Amy Mainzer, a scientist at agency's Jet Propulsion Laboratory, said the atmosphere acted as a shield.
The shock wave may have shattered windows, but "the atmosphere absorbed the vast majority of that energy," she said.
There was no immediate word on any deaths or anyone struck by space fragments.
President Vladimir Putin summoned the nation's emergencies minister and ordered immediate repairs. "We need to think how to help the people and do it immediately," he said.
Some meteorite fragments fell in a reservoir outside the town of Chebarkul, the regional Interior Ministry office said. The crash left an eight-metre crater in the ice.
Lessons had just started at Chelyabinsk schools when the meteor exploded, and officials said 258 children were among those injured. Amateur video showed a teacher speaking to her class as a powerful shock wave hit the room.
Yekaterina Melikhova, a high school student whose nose was bloody and whose upper lip was covered with a bandage, said she was in her geography class when a bright light flashed outside.
"After the flash, nothing happened for about three minutes. Then we rushed outdoors. ... The door was made of glass, a shock wave made it hit us," she said.
Injuries on this scale extremely rare
City officials said 3,000 buildings in the city were damaged by the shock wave, including a zinc factory where part of the roof collapsed.
The vast implosion of glass windows exposed many residents to the bitter cold as temperatures in the city hovered around – 9 C. The regional governor immediately urged any workers who can pane windows to rush to the area to help out.
Some fragments fell in a reservoir outside the town of Cherbakul, the regional governor's office said, according to the ITAR-Tass.
A six-metre-wide crater was found in the same area, which could come from space fragments striking the ground, the news agency cited military spokesman Yaroslavl Roshchupkin as saying.
Reports conflicted on what exactly happened in the clear skies. A spokeswoman for the Emergency Ministry, Irina Rossius, told the AP there was a meteor shower, but another ministry spokeswoman, Elena Smirnikh, was quoted by the Interfax news agency as saying it was a single meteor.
'A shooting gallery'
Meteors typically cause sizeable sonic booms when they enter the atmosphere because they are travelling much faster than the speed of sound. Injuries on the scale reported Friday, however, are extraordinarily rare.
Russian news reports noted that the meteor hit less than a day before the asteroid 2012 DA14 is to make the closest recorded pass of an asteroid — about 28,000 kilometres. CBC reporter Bob McDonald said the asteroid is coming from a different direction than the Russia meteor.
"We do live in a shooting gallery," McDonald said. "It's one of the hazards of living in a dirty solar system."
McDonald explained that when the space rock "hits the air, it comes to a screeching halt, and the pressure of the air and the heat on the front side of it, compared to the back side, causes the whole thing to collapse in on itself, and it does that so quickly that there's just this massive air burst explosion."
McDonald said the tiny pieces that do make it to the ground will be picked up by people so scientists can determine the exact makeup of the meteorites.
Donald Yeomans, manager of U.S. Near Earth Object Program in California, said it is far too early to provide estimates of the energy released or provide a reliable estimate of the original size.
The site of Friday's spectacular show is about 5,000 kilometres west of Tunguska, which in 1908 was the site of the largest recorded explosion of a space object plunging to Earth. That blast, attributed to a comet or asteroid fragment, is generally estimated to have been about 10 megatons; it levelled some 80 million trees.
Russian politicians react
The dramatic events prompted an array of reactions from prominent Russians.
Prime Minister Dmitry Medvedev, speaking at an economic forum in the Siberian city of Krasnoyarsk, said the meteor could be a symbol for the forum, showing that "not only the economy is vulnerable, but the whole planet."
Vladimir Zhirinovsky, a nationalist leader noted for vehement statements, said "It's not meteors falling. It's the test of a new weapon by the Americans," the RIA Novosti news agency reported.
Deputy Prime Minister Dmitry Rogozin said the incident showed the need for leading world powers to develop a system to intercept objects falling from space.
"At the moment, neither we nor the Americans have such technologies" to shoot down meteors or asteroids, he said, according to the Interfax news agency.
With files from CBC News