Although it is likely to be of little consolation, the 500 or so people injured in Russia by an exploding meteorite now hold a unique place in history. As far as we know, this is the first case of an incoming chunk of space debris resulting in mass casualties.
Extraordinary footage taken by residents of the Ural city of Yekaterinburg shows a fireball brighter than the Sun hurtling overhead, leaving behind a roiling, smoky trail. Its passage was followed by a titanic detonation as the object exploded, either in the atmosphere or as it struck the ground somewhere in neighbouring Chelyabinsk Oblast; the shock wave rocking buildings and shattering countless windows.
Our planet is constantly subject to bombardment by space debris, a thousand tonnes or