Originally posted by Turnsky
can't dis the original Sci-Fi books.
I love War of the Worlds. I still reckon that the original alien invasion story is one of (if not THE) best alien invasion stories.
I wasn't saying that no books have non-humanoid aliens. Just that there are far too few which do.
The saddest fact is that Wells' aliens looked nothing like humans (or anything particularly Earthlike at all). Yet instead of following in the footsteps of the inventor of the genre later authors turned their backs on true aliens and gave us little green men.
If anything War of the Worlds was an example of how to do it right.
Originally posted by Da Vinci
Firstly, I was speaking generally; creatures 20ft tall are possible, I was only discounting the idea of 100 metre tall giants (al la the alien skeleton in the first Alien film).
I agree in part with you here. 100ft tall bipedal alien giants are pretty ridiculous as they would snap their legs off when they attempted to walk. Then again I can't think of anything that has truely huge giants in it. It's worth remembering that there are stronger natural materials than bone though.
Originally posted by Da Vinci
The assumption on size comes from the idea that there is an optimum size for the life-form that sits at the top of the food chain (can you think of any land-based creature at the top of food chains on this planet that are much bigger than us?).
Nothing alive now but you mentioned dinosaurs yourself. Besides who says that a sentient species would have to be land based? Dolphins aren't that far down the scale from us but lack the opposable thumb. The octopus also was a good candidate but it also has certain realities of biology working against it on Earth. None of that preculdes a sentient race developing in the oceans of another planet.
Sure we'd be unlikely to see them on Starships unless another race gave them a leg up but it's a possibility.
Originally posted by Da Vinci
I once read a dissertation on the idea; basically it boils down to mechanics: the idea that larger creatures are too inefficient to sustain themselves forever (in our gravitational field). There was evidence that this article cited that the dinosaurs were on their way out before any cataclism occurred. Certain scientists believe that it was because they were simply too big. If you look at life that is that big, imagine what happens when it falls over, or tries to rest; its own mass will tear the body apart. Even elephants today cannot lue down for long because their own weight will crush their organs. The pulmonary system in giraffes gives them Massively overdeveloped hearts because they have to pump their blood so far. Evolution can be flawed in the short-term, the traits for survival at any given point in time are not neccessarily going to be a long-term benefit to a species.
I don't buy it. Even if you believe that the dinosaurs might have been on the way out when the asteroid killed them off the fact remains that they had been around for 160 million years before that. For humanity 160 thousand years is a long time. Seems rather ludicrous to me that someone can say that the dinosaurs went extinct simply cause they were too big. They weren't too big for 160 million years after all. If a change in climate did them in it doesn't follow that a similar change in climate wouldn't have happened on an alien planet before a large race achieved sentience.
Had the asteroid not hit I doubt the dinosaurs would have gone completely extinct any more than they went completely extinct at the end of the triassic or jurassic periods. The conditions at the end of both periods led to what might have looked like the dinosaurs going out completely too but both times they just came back bigger and stronger.
Originally posted by Da Vinci
With size it's a matter of efficiency.....an intelligent being needs to be big enough to defend itself against predators and have a long enough lifespan to develope as a society, but be small enough be able to concentrate on things apart from eating enough to sustain its body.
I'll agree with you that it's likely that an intelligent being is likely to be a social animal as solitary creatures are unlikely to advance enough to make spacecraft but I disagree that the amount of leisure time a creature has is solely a function of it's size.
If you look at the big cats they all spend much less time hunting for food than the great apes do. A lot of evidence points to the fact that the big predatory dinosaurs (with the possible exception of T-rex) were similar in habits to the great cats. That makes them prime candidates for intelligence as they would be doing precisely the same thing that lead to humans developing intelligence (chasing larger prey on open ground). As soon as an allosaurus came up with the idea of hitting a stegasaurus with a diplodocus leg bone we've got the beginnings of sentience right there.
Originally posted by Da Vinci
I find this a fairly convincing and interesting argument.....it's an assumption, yes; but so are most theories about evolution and developement of life
It's too narrow an assumption for my liking.
