An explosion above the Podkamennaya Tunguska (Stony Tunguska) River region of central Siberia at about 7.30 a.m. local time on 1908 June 30, caused by a large stony meteorite or cometary fragment. A fireball as bright as the Sun detonated in mid-air, producing dust which caused abnormally bright nights across Europe for days afterwards. Expeditions to the site found a vast (2200 km2) area of devastation, with trees knocked over and scorched up to 40 km away, but no craters were found. The incoming body is thought to have been 50–100 m in diameter, and to have exploded 8–9 km above the ground with the energy of 15–20 megatonnes of TNT.
Subjects: Astronomy and Astrophysics.