Extraterrestrials are not so alien


By Morris Jones

We haven’t found extraterrestrial intelligence yet, but that hasn’t stopped us from wondering what they would be like. Science fiction has plenty of answers, with just about anything you could imagine meeting up with the crew of the USS Enterprise at some point. But there’s one overwhelming trend in sci-fi. Aliens look humanoid. That’s understandable for some reasons. It’s much easier to dress up an actor in a rubber suit or put green make-up on his face than construct an animatronic fifty-legged giant insectoid with five heads. Sci-fi shows make extraterrestrials not too different from us for economic reasons. But they could be on to something more realistic than they know. Extraterrestrials will almost certainly look different from humans, but they will probably not be as wildly different as some fantasy writers expect.

There’s a wide-spread diversity of life on Earth, big and small. But most of it isn’t really smart. Most lifeforms do not even have brains. You need a lot of very specific physiology in order to be intelligent and capable of building a technological civilization. Most creatures don’t even come close. Those that do better than most all have some common elements.

You need a brain, and it had better be a large and good one. You need to be able to move around. You need to grasp objects and handle them with skill. You need to be able to see very well. Your sensory organs should be fairly close to your brain, so signals travel quickly. You also need structures and organs to keep all of this together. Thus we have common elements in physiology that can’t be avoided.

The laws of science that govern the way matter behaves in our bodies won’t be different for extraterrestrials. Thus, without even discovering them, we can make some fairly solid conclusions about their biology. Some types of micro-physiology and macro-physiology just don’t work. You can’t be too big, too small or too weak.

This doesn’t mean that extraterrestrials won’t look strange. They could have different combinations of limbs, more eyes, and things that play the same role as our hands and feet, but don’t really look like them. They may lack some sensory inputs that are critical to us, such as hearing. They may be more sensitive in some sense than we are. But try anything more different, and they will not be able to live. Science and biology have shown this too many times. Some limits can’t be avoided.

We can make some fairly good assumptions on the physiology of extraterrestrials, but we can only go so far. There could be structures that we have not encountered in life on Earth that could still work. Some may not have been conceived in science fiction. In the meantime, we have plenty of room for speculation.

This could prove to be beneficial in the future, should we ever attempt to communicate with extraterrestrials. It means that we will probably have more in common than we may initially suspect. This, in turn, could help us to understand each other. We can thus know a fair amount about extraterrestrials by knowing about homo sapiens. Right now, it’s a lot easier for us to study that form of intelligent life than one in a different star system.