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On July 25th, 2001 a strange rain began to fall over Kerala, India. For three months intermittent reports of colored rains came in from a several hundred kilometer long strip of coastal India. Just prior to the first reported cases of red rains, reports of sonic booms in the Kerala region suggested that perhaps a comet or asteroid had disintegrated high in the atmosphere, a phenomenon known as an airburst. Two scientists, Godfrey Louis and A. Santhosh Kumar, collected samples of the red rain and reported that the red coloration came from some unidentified particle which showed biological activity. Did Louis and Kumar uncover the first hard evidence of alien life here on Earth?

The notion that extraterrestrial life is occasionally transported to Earth, or perhaps even originally seeded life on Earth itself, is known as panspermia. The philosophical concept of panspermia has an ancient history, but it gained some scientific credentials with the support of Lord Kelvin in the late 19th century. He and others noted that meteorites often contained organic material that could only be explained by biologic activity. In the early 20th century, the Nobel-prize winning chemist Svante Arrhenius calculated that seeds or spores could be transferred from Earth to Mars in a few days, and to our nearest stellar neighbor Alpha Centauri in just under 10,000 years. A few decades later, one of the world’s premier astronomers, Fred Hoyle, advanced the panspermia cause with his view that periodic infusions of extraterrestrial life helped to advance genetic evolution of life on Earth.

But panspermia fell out of favor, as did many ideas about extraterrestrial life, when Mariner 9 returned images of Mars showing it to be a rocky, desolate wasteland. For two decades panspermia was not not widely supported, but gradually over the last decade panspermia has become scientifically fashionable again. Astronomers have discovered increasingly complex organic molecules in interstellar clouds, and in 1996 geologists announced the discovery of structures within a Martian meteorite that appeared to of biologic origin. That claim has since been largely refuted, but just last week another Martian meteorite was announced that supposedly contains unusual compounds and structures that indicate extraterrestrial life activity.

So did alien life rain down over Kerala during July of 2001? Louis and Kumar have published three scientific articles in peer-reviewed journals supporting their claim. They note that the pattern of colored rain reports matches what would be expected if a meteorite released tiny spores that gradually rained down over the land. Also, they report that the spores can be induced to reproduce and grow, and that higher temperatures cause higher growth rates.

But scientists are a skeptical lot, and extraordinary claims require extraordinary evidence. So far, Louis and Kumar are alone in their publications. Other scientists have presented evidence that dust storms around the Horn of Africa and in the Middle East lofted thousands of tons of dust and fungal spores into the atmosphere that traveled over to India and were washed out by the monsoonal rains. Louis and Kumar have criticized this hypothesis, but have not yet conclusively demonstrated the extraterrestrial origin of their red rain spores.

Though scientists are sometimes insular and overly-conservative, if firm evidence of extraterrestrial life exists it would have been promptly published. After all, such a publication would assure eternal fame for both the scientists and the journal itself. Until more convincing evidence emerges, panspermia will remain an idea slightly on the fringes of science, but firmly within the mainstream of the paranormal.