109 years since largest asteroid impact in recorded history
The Tunguska asteroid event in Siberia which occurred on this day in 1908 is considered to be largest asteroid impact in Earth's recorded history. NASA estimates a 50-metre-wide fireball entered Earth's atmosphere at over 50,000 kmph releasing energy equivalent to 185 Hiroshima atomic bombs. United Nations has marked June 30 as the International Asteroid Day for raising awareness about asteroids.