On 25 July, 2001, blood-red rain fell over the Kerala district of western India. And these rain bursts continued for the next two months. All along the coast it rained crimson, turning local people's clothes pink, burning leaves on trees and falling as scarlet sheets at some points.Investigations suggested the rain was red because winds had swept up dust from Arabia and dumped it on Kerala. But Godfrey Louis, a physicist at Mahatma Gandhi University in Kottayam, after gathering samples left over from the rains, concluded this was nonsense. 'If you look at these particles under a microscope, you can see they are not dust, they have a clear biological appearance.' Instead Louis decided that the rain was made up of bacteria-like material that had been swept to Earth from a passing comet. In short, it rained aliens over India during the summer of 2001.