In an article in the International Journal of Astrobiology, P. McCafferty discusses the possibility of a red, blood-like life form living inside meteors.

This conclusion raises the possibility that, in space, there are objects that contain red, blood-like cells. In other words, comets possibly harbour life. Such an image of a comet, containing a liquid interior teeming with red cells, is difficult to imagine and even harder to accept. So when faced with the prospect that the fall of red rain in Kerala is extraterrestrial in origin, it is tempting to apply Occam’s Razor and to dismiss any link between red rain and a meteor as a coincidence.

In his defense, he quotes Thomas Jefferson’s response to meteor sightings which he (Jefferson) believed to be ridiculous.

‘it is easier to believe that two Yankee professors would lie, than that stones should fall from the sky’

But, stones DO fall from the sky. McCafferty makes the point that sometimes the simple answer is wrong. Quantum physics, and much of molecular biology provide plenty of examples of conclusions that don’t fit in with our intuitions. That said, once we study a bit harder, the conclusions do finally make more sense (well … mostly).  Most people find anything at all to do with calculus (basic calculus) totally incomprehensible and out of touch with their view of the world.  But, they're wrong. 

Perhaps after some time (and assuming the theory of red cells in the sky holds any water), the idea of life in space won’t seem so crazy (eg. hear Carl Zimmer discuss methane gas potentially produced by bacteria on Mars on Blogging Heads).

Altogether, there are at least 80 accounts of red rain, another 20 references to lakes and rivers turning blood-red, and 68 examples of other phenomena such as coloured rain, black rain, milk, bricks, or honey falling from the sky. These phenomena have occurred throughout the centuries and in many different locations from Classical Rome to medieval Ireland, Norman Britain and 19th century California to 21st century India.

Interesting …

It has become increasingly appreciated that, in addition to their cargo of ice and dust, comets also contain a large amount of organic material. In 2004, the Deep Impact Spacecraft, which slammed a separate, smaller craft into Comet Tempel 1, revealed an extraordinary amount of organic material, with polyaromatic hydrocarbons and amino acids (JPL 2006). It is now more widely accepted that complex organic molecules can be formed in interstellar space; it is understood that bacterial life is amazingly resilient and could even survive the extreme conditions of entry into earth’s atmosphere. Increasingly, the idea of panspermia, with comets as the source of life on Earth (Hoyle&Wickramasinghe 1999), is no longer seen as quite so outlandish.

But, here’s the yummy part.

Perhaps, though, the first few generations of extraterrestrial red cells would find the habitat on earth less than the optimum and would exhibit breeding characteristics wildly different from most earthly species. Experiments on the red rain from Kerala apparently demonstrated that the cells reproduced at high temperatures (Louis&Kumar 2003), which may offer an explanation for some rather bizarre ancient reports: in Rome, in 91 BC, ‘at sunrise a ball of fire shot to the heavens with a huge noise; bread was broken and blood oozed from the middle’ (Obsequens, liv). Centuries later, in AD 806, in Ireland, a similar event occurred: ‘the cakes were converted into blood, and the blood flowed from them when being cut’ (O’Donovan 1848). In AD 1161, in Brittany, a famine was ‘preceded by a blood-rain in the diocese of Dol; rills of blood ran from a fountain, and bread when cut shed blood in abundance’ (Tatlock 1914, p. 443). These reports are quite strange, but who knows, perhaps some ingredients for Roman bread or Irish cakes were contaminated with extremophilic red cells, which thrived and multiplied in an oven and later oozed from the baked bread.

Moral? Never bake bread with space flower!