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| a dashboard camera takes,the meteor streaks through the sky over Chelyabinsk |
The meteor which closely missed the Russian city of Chelyabinsk on
Friday is likely to go down in history as the largest celestial body to
have hit the Earth over the past hundred years.
NASA scientists said the object was a tiny asteroid that released 300 to
500 kilotons of energy when it exploded, which is roughly equivalent to
20 atomic bombs of the type dropped on Hiroshima and Nagasaki. This
would make the Chelyabinsk meteor the largest since 1908 when a meteor
hit Tunguska in Siberia, levelling an estimated 80 million trees. The
energy of the Tunguska blast is estimated to have been up to 50
megatons.
“It was something like Tunguska – a 60-metre cosmic body, which fell
into the Tunguska taiga in 1908,” said Dr. Oleg Malkov of the Russian
Science Academy Institute of Astronomy.
Scientists believe the Chelyabinsk meteor was about 17 metres across and
weighed 10,000 tons. Shock waves from its explosion over Chelyabinsk
wounded 1,200 people and shattered doors and windows in 3,724 apartment
houses, 671 schools and 235 hospitals and outpatient clinics. What saved
the city was that the explosion occurred 30 to 50 km above the ground.
Chelyabinsk governor Mikhail Yurevich said it was a very close brush for the region with a population of 3.5 million people.
“I think yesterday was a second birthday for our region and its
residents,” he said on Saturday after inspecting the damage. “Had the
meteor been a little bigger, it would have caused a real catastrophe.”
Meanwhile scientists are excited at the prospects the Chelyabinsk meteor offers for a deeper insight into the solar system.
It was the biggest celestial body ever observed on its flight through
the atmosphere and there was a good chance of finding its fragments
before they get contaminated by exposure to the elements.
Divers on Saturday searched the bottom of frozen Lake Chebarkul about 80
km from Chelyubinsk where a chunk of the meteor is believed to have
plunged, but found nothing.
Scientists said the Chelyabinsk meteor's close miss should serve a
wake-up call for the international community to set up a system for
monitoring meteors of similar size and providing advance warnings to the
population.
“Today we can spot about 10 percent of such objects as the Chelyabinsk
meteor in the solar system,” said Dr. Malkov. “Ninety percent go
undetected and some of them may crush on Earth any time.”
Politicians backed calls for greater international effort to combat cosmic threats.
“Instead of building a European missile defence system, the United
States should join us and China in creating the AADS – the Anti-Asteroid
Defence System,” said Alexei Pushkov, head of the International
Committee of the State Dume, the lower house of the Russian Parliament.