The distribution of red rain in time is problematic. Godfrey Louis does a good job of explaining how a 10 micron object can linger in the air for long periods of time but ignores the fact that the same forces that keep it in the air would allow it to be carried great distances by wind. The chances of meteorite fragments drifting down exactly below where they were originally ablated months after the fact are nil. It is telling that the trail of the putative meteorite happens to coincide with the southern end of the west coast of India. The west coast is different from the rest of India. Immediately beyond the coast rises the Western Ghats (in the far south, the Cardamom Hills), which by orogenic uplift wring water out of the prevailing winds coming from over the Arabian Sea. Thus the thin strip of land before this mountain chain is tropical with rain throughout the year, unlike the semi-raid region just to the east. It boasts an extremely high population density due to the favorable climate, and this large population would have been on the lookout after the initial reports of colored rain hit the news. It is thus probable that the phenomenon involves dust from Africa or the Arabian Peninsula getting washed out of the air over the coast, rather than a meteor.

The descriptions I've seen of the red rain don't say whether it was visibly red when it fell or whether it was declared red after it was noticed in standing pools of collected rain. Since the original rain was reported as falling at night, and the standing pools themselves aren't strongly tinted (meaning individual drops were almost clear), the latter is likely. If so, perhaps nutrients dissolved in the rainwater triggered the growth of a terrestrial microorganism. No mention is made of sample collection methods or of any attempt to isolate individual colonies of the putative space organism. Since many terrestrial organisms have spore forms that persist in the atmosphere, an attempt must be made to isolate the red cells from other more mundane organisms.

Much is made of the absorption properties of red cell solutions in the UV region of the spectrum, to match anomolous UV absorption in space. Real biologists would find this interesting, but since many biological molecules absorb UV, they would be much more interested in the spectral characteristics in the visible portion of the spectrum (consider chlorophyll, carotenoids, hemoglobin, etc.). This is especially true considering the red coloration of the cells. Some component must be absorbing light in the blue-green end of the visible portion of the spectrum. The graphs shown suggest an almost flat absorption in the visible, which would doesn't explain the red coloration. I'd have preferred to see visible light absorption spectrums of more concentrated samples.

The use of Ethidium Bromide to detect DNA has problems. It has a certain background flourescence, which means there is a minimum detectable concentration which is indistuinguishable from a non-DNA-containing Ethidium Bromide control. It is also interesting that he noted no DNA after grinding the cells, but proudly proclaimed the uptake of Ethidium Bromide by whole cells as evidence of biomolecules. DNA is a long fragile molecule. Perhaps grinding cells is not the best way of preserving it. There's also the unfortunate fact that the biological world is rife with DNases, whcih like to snip DNA into bitty pieces. Even in the cleanest and most sophisticated biology labs, problems with these are encountered. This might explain the lack of DNA from the original red cells (which had probably already used up the nutrients and thus were mostly dead). And finally, as Godfrey Louis himself noted, DNA is not stable at the pressure and temperatures at which he was 'growing' the cells. The other DNA test changed color, but not the expected color. This could mean no DNA, or perhaps it turned the right color but was mixed with a cell component of another color?

Perhaps the most interesting part of the experiments is the alleged cell growth at 300 degrees C. What is happening here is less certain, but I'll hazard a guess. Lipids such as comprise cell membranes are more water soluble at high temperatures. Dissolution of the membranes resulted, especially with the help of the 'growth' media, which contained various oils or alcohols and other strange items. In order to obtain turbidity measurements, though, the culture was depressurized and cooled. Lipid membranes spontaneously reformed, perhaps wrapping around cellular debris. Their size and number would depend on the rate of depressurization and cooling. The cultures were "recovered from the pressure vessel after fast cooling", so he started with a few large cells and ended up with many small lipid vesicles. Growth indeed.