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Wednesday, November 28, 2012

Speculative Biology: Organisms Floating in the Atmosphere 

With each passing year, it seems that we discover Evolution using physical principles in new and surprising ways. It is clearly dangerous to assume that some kinds of adaptations will not be found in organisms. If it is physically possible, Nature seems happy to do it.

Fortean Times recently (August 2012) had a highly speculative cover article by Scott Deschaine asking if some UFOs are not actually living creatures. I don't think this is the least bit likely, but I was interested in a letter of critique published in the November 2012 issue of the same magazine. Among other things, the writer, Martin Jenkins, writes that an organism floating high in the atmosphere could not rely on a lighter-than-air gas, because hydrogen and helium would be unavailable. And that the alternative of heating its internal air to achieve buoyancy like a hot-air balloon would be prohibitively expensive in terms of energy.

However, Mr Jenkins has forgotten that the following gases are also lighter than air, and are feasible as biological products: carbon monoxide, ammonia and methane. The two latter gases have, in fact, been used to provide lift for balloons. Also, in terms of producing a great deal of heat very quickly, the bombardier beetle can actually produce a boiling liquid to protect itself from predators. I cannot see any necessary objection to an organism producing heat to warm air to help keep itself aloft.

So, neither of these two objections seems strong. This is not to say that I believe we will find large organisms floating high in the atmosphere. But I would not be amazed to read eventually, for example, of an insect using methane or ammonia to help it remain aloft. Insects produce ammonia as a waste product which occurs in the gut.

(I have been wondering if the giant flying insects of the Carboniferous, including the "dragonflies" of the time, could have had a boost from lighter-than-air gases inside their bodies or wings, although the usual explanation given is that the atmosphere of the time contained more oxygen or was denser, both of which would have allowed large insects to fly more easily.)

One further objection to the theoretical existence of large unknown creatures living high in the atmosphere is that we should be able to see them. However there are plenty of animals which are largely transparent.

I suspect one of the stronger objections to Deschaine's speculations is that we do not observe the detritus of unknown organisms raining down on us, in an analogous way to the constant deposition of organic material on the sea bed.

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