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Quite Strange

Entry 520, on 2007-04-26 at 16:17:48 (Rating 1, Science)

Many people have speculated on the chances of there being life in the Universe outside of the Earth. It has been pointed out that the strange fact is that we don't see life everywhere. According to calculations (or maybe that word indicates too much precision and estimates, or even guesses, would be better) based on the famous Drake Equation, there should be life everywhere, and much of that life should have evolved to a point of being intelligent enough so that we could detect its presence.

So the odd thing about the Universe is that we don't see any signs of other life. We might not expect to be visited by intelligent aliens, because its a big Universe out there, and we haven't really been capable of noticing and recording visits for long, but we should be able to see indirect signs that advanced life exists.

The most obvious sign of intelligence are signals from communications systems and other devices which use radio and other wavelengths of the electromagnetic spectrum. A bubble of this radio noise has been expanding away from the Earth for 100 years, so it now covers a volume of about 4 million cubic light years. Any alien civilisation with technology similar to ours could detect it.

There is a reason I have launched into a discussion of this particular topic. Its the discovery of the most Earth-like planet yet, orbiting the red dwarf star Gliese 581. This planet might have liquid water, and is only slightly bigger than Earth. For the first time we know that planets similar to our own exist, and this should make the likelihood of life in the Universe far greater, yet we still don't see it. It is quite strange.

Just one last comment. This shouldn't be used to support claims supporting alien spacecraft sitings, abductions, etc. Even if life is more likely in other parts of the Universe we shouldn't use that fact to support pseudo-scientific theories. If UFOs really are visitors from other planets it should be a lot more obvious to everyone.

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