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March 05, 2006

Xenobiology 

How would aliens look like? I bet many have asked themselves this question, either as daydreaming or as a more serious intellectual exercise.

I am fairly convinced that there is life on other worlds. There is no real proof (yet), but seeing how stubborn and adaptable is life on Earth, I suppose that simple organism can be found also on other planets or bodies. We aren't even sure we know all the forms life can take on Earth, actually. The variety of possible alien lifeforms is infinite.

But if we talk about intelligent and technologically capable aliens, that may travel across the stars and eventually pay us a visit, the field is much more restricted. Let's consider Earth again: there are thousands of species of vertebrates (not to mention all the rest), but only Homo sapiens sapiens developed structured language(s) and writing, mastered science and technology, philosophy and metaphysics. Our closest relatives, the chimps, are a long way behind us on this road. Another point to notice is that modern humans are the product of one particular evolutive history - but there is no real compelling reason for us to be exactly like we are.

So, I think it would make more sense to think about what characteristics space-travelling aliens must possess. Building ships for space travel is by no means easy, especially if these ships have to carry a living crew. It takes advanced phisycs, chemistry, materials science and mechanical engineering to design and build one - plus of course all the advanced mathematics behind all this. If those ships use anything nuclear (which is a distinct possibility), also quantum mechanics becomes necessary; even excluding the much vaunted faster-than-light flight.

The notation used by an alien race would be radically different, but the concepts must be there. For example the hexagon is not just an human abstraction, but it's a figure encountered often in nature - the benzene molecule, the quartz crystals. I think that someone already said that mathematics could be the true universal language.

Thus, our aliens must have a few fundamental features:

- A well-developed nervous system.
This may or may not require a central brain in the body, and alien societies may even be hive-minds; however single individuals must be quite independent if they have to conduct an interstellar mission.

- Sensorial organs.
But exactly what senses, is too difficult to say. It depends from the evolutive history of each particular species: for examples, humans are fairly limited in this regard; other earhtly animals can sense electro-magnetic fields, infrared rays and ultraviolet light.

- Complex, high bandwidth communications
For this purpose humans use audio-visual coding (speech and writing), but these aren't strictly the only systems available. Other species may have evolved the capacity to project complex images without the need of supports; or may use chemical messengers (I don't think this is very likely, but that's just me). It is even conceivable that some aliens may be able to communicate directly with each other using electro-magnetic fields - sort of telepathy.

- Manipulator limbs
These are required to manipulate objects. There is strong evidence that in humans the development of erect posture, hands and brain has been strictly interconnected. However, the bone-and-muscle uman hand is not the only tool for the job; aliens may have any number of prehensile tentacles with or without pincers or claws; another possible and very practical feature would be morphing limbs that can take a variety of shapes.

None of these carachteristics requires an antropomorphic body, or our human bi-simmetry. Actually, it's very likely that an alien race would look very different from us - unless humans and some aliens are related for some unknown reason. It is very improbable, but not physically impossible that aliens may have tampered with the course of evolution on Earth and thus originated mankind.

However, the fact that most alien sightings describe them as rather humanlike is another reason to be skeptical for me. The pointed questions would be others: why these aliens do not send unmanned probes first - and why we never found the remains of such probes landed in the past? Why would these aliens be so shy? If they truly are so advanced technologically, our best weapons would be no real threat to them. And if they wanted to observe us unobtrusively, they did a quite poor job. Why aliens do not attempt to communicate with us thorugh more "official" channels? They should be smart enough to figure out how our society works. If they wanted to conquer us, why not send an assault fleet and vaporize all resistance with high-power X-ray lasers and antimatter bombs?

(Ok, thinking about it, they may be post-modern and politically correct aliens. You may nver know)

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