Asteroid security 

Asteroid Day tries to save life as we know it

It would be the end of the world as we know it. A relatively small lump of rock – a small asteroid, perhaps only a few hundred metres across – plunging to Earth would devastate a continent or trigger tsunamis. Civilisation would be set back several centuries.

It is a real risk, say a group of astronauts and astronomers who are to highlight the threat facing humanity by marking 30 June as Asteroid Day.