I stumbled onto a Popular Science article today that mentioned the mysterious blood-red rain that fell in India back in 2001. There were ideas about what caused the red rain - things like desert dust, spores, algae, etc. However, it looks like whatever caused the rain to come down red is a bit more mysterious.

Indian researcher Godfrey Louis has been studying the samples for 5 years now, and has turned up some startling findings.

Specifically, Louis has isolated strange, thick-walled, red-tinted cell-like structures about 10 microns in size. Stranger still, dozens of his experiments suggest that the particles may lack DNA yet still reproduce plentifully, even in water superheated to nearly 600¢ªF. (The known upper limit for life in water is about 250¢ªF.) So how to explain them? Louis speculates that the particles could be extraterrestrial bacteria adapted to the harsh conditions of space and that the microbes hitched a ride on a comet or meteorite that later broke apart in the upper atmosphere and mixed with rain clouds above India.