Most people will never have heard of red rain, after all in most people’s eyes rain is just colourless water falling from the skies. Coloured rain though is not an uncommon event, and has been often reported over the years. Arguably the most famous red rain phenomenon in recent years though occurred in Kerala, a southern Indian state.
The most publicised occurrence of red rainfall in Kerala occurred in 2001 when for several weeks a red or scarlet rain was seen to fall. These showers commenced in the districts of Idukki and Kottayam, before spreading to other districts. The rain though was particularly noticeable as at it fell it would dye any cloth left outside a distinctive red colour.
Almost immediately a statement was put forward providing the theory that the red rain was caused by a meteor exploding in the atmosphere. This theory though was quickly dispelled and withdrawn as red rain continued to fall for a number of weeks. Further research was undertaken and a new theory was put forward that the presence of spores as released by local algae was the cause of red rain.
Some people though are not convinced by the scientific research indicating that the red rain has been caused by spores. Testing methods were perhaps not what they should have been. Some prominent scientists have once again returned to the theory of a meteor bringing forth extraterrestrial cells that cause the red rain to fall.
Red rain may be a totally natural phenomenon or else there may be some human intervention, and industrial pollution may be a potential cause.
As previously mentioned red rain is not an unknown phenomenon, and many places across Europe especially have experienced their own coloured downpours. In most cases though, these events are put down to geological interaction with the water rather than any form of spores. European examples are normally put down to the fact that sand from the Sahara has been carried up into the atmosphere where it falls with the rain. Yellow rain is also often blamed on sand particles, although examples in Afghanistan are also said to have been caused by the presence of pollen. Sand from any desert though can not be used to explain why on some occasions black and green rain also falls, although the more uncommon nature of these coloured rains does mean a great deal more study is required before conclusions can be reached.