International Asteroid Day aims to raise public awareness about the asteroid impact hazard and to inform the public about the crisis communication actions to be taken at the global level in case of a credible near-Earth object threat.
On 15 February 2013, a large fireball (technically, called a “superbolide”), traveling at a velocity of 18.6 kilometers per second, entered the atmosphere and disintegrated in the skies over Chelyabinsk. According to NASA, the approximate effective diameter of the asteroid was estimated at 18 meters and its mass at 11,000 tons.
The approximate total impact energy of the Chelyabinsk Fireball, in kilotons of TNT explosives (the energy parameter usually quoted for a fireball), was 440 kilotons. The Chelyabinsk event was an extraordinarily large fireball, the most energetic impact event recognized since the 1908 Tunguska blast in Russian Siberia.