Red rain in Kerala
From Wikipedia, the free encyclopedia
Red rain in Kerala was a phenomenon observed sporadically from 25 July to 23 September 2001 in the southern Indian state of Kerala. Heavy downpours occurred in which the rain was primarily red, staining clothes and appearing like blood.<1> Yellow, green, and black rains were also reported. <2>
It was initially suspected that the rains were colored by fallout from a hypothetical meteor burst, but the Government of India commissioned a study which found the rains had been colored by spores from a locally prolific aerial algae.<3> Then in early 2006, the Keralan colored rains suddenly rose to worldwide attention after media reports of an extraordinary theory that the colored particles are extraterrestrial cells, proposed by Godfrey Louis and Santhosh Kumar of the Mahatma Gandhi University in Kottayam.
<snip>
Conventional theories
History records many instances of unusual objects falling with the rain — in 2000, in an example of raining animals, a small waterspout in the North Sea sucked up a school of fish a mile off shore, depositing them shortly afterwards on Great Yarmouth in the United Kingdom.<11> Coloured rain is by no means rare, and can often be explained by the transport of dust from desert regions in high pressure areas, where it mixes with water droplets. One such case occurred in England in 1903, when dust was carried from the Sahara and fell with rain in February of that year.
At first, the red rain in Kerala was attributed to the same effect, with dust from the deserts of Arabia initially the suspect. LIDAR observations had detected a cloud of dust in the atmosphere near Kerala in the days preceding the outbreak of the red rain <12>. However, this hypothesis could not explain certain aspects of the red rain, such as its sudden onset and gradual decline over two months, and its localisation to Kerala despite atmospheric conditions that should have seen it occur in neighbouring states as well.
Another theory is that the rain contained mammalian blood, a large flock of bats having been killed at high altitude, perhaps by a meteor. Some bat species in India live in very large communities. However, no bat wings or other remains were found raining from the sky, and no known process would separate the red blood cells from white cells, platelets and other blood components. Red blood cells disrupt rapidly in regular rainwater because of osmosis, but this was not evident with the red particles.<13>
More:
http://en.wikipedia.org/wiki/Red_rain_in_Kerala#Conventional_theoriesI'm fascinated by this!
I'd like to devote a couple hours to reading more, but I don't have time.