On 15 February 2013, a bright meteor appeared in the skies over Russia at about 09:20 YEKT (03:20 UTC). Travelling at 18km/sec (40,000 mph),
it quickly became a brilliant fireball as it passed over the southern Ural region, exploding in an air burst over Chelyabinsk Oblast at about 15 to 25 km
the ground. The atmosphere absorbed most of the released energy,[7] which was equivalent to nearly 500 kilotons of TNT making it 20–30 times more
powerful than either of the atomic bombs detonated at Hiroshima and Nagasaki.
About 1,500 people were reported injured, two in serious condition. All of the reported injuries were due to indirect effects rather than the meteor itself, mainly by glass
from windows shattered by a shock wave. Over 4,300 buildings in six cities across the region were damaged by the explosion. The meteor created a dazzling light,
bright enough to cast moving shadows during the morning daylight in Chelyabinsk and was observed from Sverdlovsk, Tyumen, Orenburg Oblasts, the Republic of
Bashkortostan, and in Kazakhstan. Eyewitnesses also felt intense heat from the fireball.
With an initial estimated mass of 10,000 tonnes, the Chelyabinsk meteor is the biggest object to have entered the Earth's atmosphere since the 1908 Tunguska event,
and the only meteor known to have resulted in a large number of injuries. The object was not detected before atmospheric entry.