How different can be aliens?

The whole idea is that these “aliens”.. whoever they are.. if they were to find us they must be much farther along the evolutionary chain then us, thereby looking very different. Not only that, alien movies are a lot more fun when the aliens don’t look like us.

Well they would be quite different from us at least appearance wise. For example the prawns in Disrtict 9 are actually a good candidate for what they might look like. You are quite correct in assuming that they would have things like eyes, ears, mouths, appendages and so and so on but what those might look like is anybodies guess. The chances that Aliens looking very much like humans is so insanely improbably most people wouldnt even bother counting that as a possible outcome. I’d suggest looking at Drakes equatiation for the chance of there being life in this galaxy. Also look the bottom of the page for other related theorys. Also why is it that you dont believe that they exist or is that just a typo?

i agree.
for the number of legs, it has to be stable, it must enable good movement and it should consume as little energy as possible. 2 legs is not stable enough in the first stages of evolution, 3 legs are stable, but suck at movement, 4 legs is where the gold is at. more than 4 need too much energy and would hinder the development of intelligence( just look at spiders). 4 legs leaves the 2 of them available for later evolution into hands when becoming bipedal.

for sensory organs, they need sensors for light, sound and smell for maximum survivability. for the number of eyes and ears, 2 are necessary and sufficient for locating the source via triangulation. it would also be good if they were very close to the data processing centre/brain, meaning they would be combined in one structure, e.g. head and this structure would also be well above the ground for optimal situational awareness.

So in summary, an intelligent species would very likely be humanoid in appearance, but of course details may vary, such as arrangement of the sensory organs on the head, the actual physiology of the sensory organs, the number of joints of the limbs, whether knee(s) are bent forwards or rearwards, number of fingers/toes (while i think for hands, 3 fingers and 1 thumb should be sufficient).

We have decended from mammals. But aliens might come from reptiles, or birds, or huge insects. For example, crocodile society is pretty organised and, given a few million years without human intervention, perhaps they’d rule the planet. Or maybe dolphins could do that. I know it sounds silly, because they live in water, but who’s to say that this other planet has any land at all? And as for their spaceships, going from land into the air and then outer space is no easier (or harder) than going from water into air and outer space.

Also, their planet could be much smaller, and everything would then be on a different scale. They could live on a tiny rock with no water, and feed on coal or molten lava. They could even be made of silicon, rather than carbon. Or they could be insects with tiny little spaceships, the size of a human thumb. On a galactic scale, a spaceship 1 inch tall is not much different than a mile-long rocket. Plus insects have more hands to work with, and are better organised than us. All they lack is a brain (and who’s to say they couldn’t develop this on a distant planet, given enough time?).

Their planet probably doesn’t even have any creatures similar to us, and we’d look just as alien to them as they do to us. They probably have no bipeds at all, or even mammals (or else something resembling ourselves would have probably come out of that, as you suggest). But even if they were little green men, or apes for that matter, the evolutionary road would have branched off early enough to make them entirely different (humans had 6 fingers at some point in the distant past, so who’s to say these creatures won’t have scales, tails and antennae?).

Flowers, Trees, and humans share 75% of the same DNA.
Jellyfish, however, don’t. They seem to have formed independantly.
That’s how different we can be, and we are from the same planet. Imagine other origin.

Find a good science fiction book and read it. Larry Niven has some good stuff.

You sound like you’ve been corrupted by the Star Trek and Star Wars universes, which for expediency sake in filming somewhat requires aliens with humanoid construction.

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Different planets have different gravity from Earth, different length of days, may or may not have seasons, different component gases in the atmosphere… all kinds of things. Furthermore, if you subscribe to random-chance evolution theory as the route that gives rise to life and ultimately intelligence, then the result would almost necessarily have to look wildly different than anything in our current catalog of expectations.

I think that aliens that evolved under different circumstances would appear as something completely NOT bipedal. Just because the beings on Earth developed with paired sets of limbs, that doesn’t mean the evolution of other beings on other worlds would follow the same path. Single limbed creatures, or non limbed creatures are entirely possible, given the proper environment in which to evolve.

Spiders the size of elephants could evolve an intelligence to compare or exceed humanity, all it would take is the proper gravitational and proper natural influences. To assume that aliens are going to look like us is foolish. They could be gaseous, or of a size we do not consider large enough or small enough to be sentient.

I have always liked the quote: The universe is not only as strange as we imagine, it is stranger than we can ever imagine.

@robmandu, in Star Trek, the reason Roddenberry made the aliens humanoid was to keep costs down. It;s easier to just apply make up than it is to create whole new exotic creatures on a limited budget.

“There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.

“There is another theory which states that this has already happened.”

—Douglas Adams

They would be either more evolved or less. But, on the same evolutionary path.

If you want to think that due to environment they would look, be or act different. Then we should also have square or triangular planets.

There is a constant to the universe.

I assume they look alot like Victoria Beckham.

If you want to get a sense of how alien other lifeforms can be, read Heaven by Ian Stewart & Jack Cohen. The main character is a polypoid—a squid-like creature who is the male of a species of sentient coral which can combine and divide itself into multiple intelligences for the purposes of computing predictive scenarios. They barter these to other species for necessary things. Each male “breaks off a little piece” of the “wife-reef” to carry with him for companionship. The wife-reef communicates via chemical signals encoded into spores which, when ingested, produce a holographic experience which conveys the message.

This character meets up with a space-faring, telepathic Neanderthal that has lion-like features that change color with her moods. Together, they meet up with an astonishing menagerie of truly alien life forms from huge balloon-like creatures that inhabit gassy Jovian-type planets, to sentient tide pools whose mental life is carried on by a division of labor among the creatures that inhabit it (one of which can read the reef-wife’s chemical messages).

It all conforms to the new biology of machines, social systems, and the economic world. Available now for only a penny at Amazon.com.

@ChazMaz so you are saying that all aliens would look much like everything that has ever evolved on earth? What about planets in which there is a stronger gravitational pull, binary suns, and various gases that are in abundance, other than the normal nitrogen/oxygen mix of earth? I think you assume that since all planets are round, due to gravitational forces, then that all beings would resemble something of earth.

I think it is hubris to assume that the life forms that exist in the universe would obviously resemble the things that exist on this planet, especially the ones that are alive today. Before the end-Permian extinction 251 million years ago, there were creatures unlike anything alive today, but we have very few records of them due to the lack of complete fossils. What we do have are pretty unusual, including saber toothed reptiles.

I am willing to bet there are beings out there that we wouldn’t even recognize as sentient because we have only dealt with the life forms of one planet, ours.

“What about planets in which there is a stronger gravitational pull, binary suns, and various gases that are in abundance, other than the normal nitrogen/oxygen mix of earth?”

Those would be unlivable planets. Only until/if they developed into a proper living environment will life develop on it.

“Before the end-Permian extinction 251 million years ago, there were creatures unlike anything alive today”

Might be “unlike” but still operating under the right process for life, which lead to who we are today. You could go back in time to a point where you might not be able to live due to the poor atmosphere. But life did exist. Primordial but still life. Not until our planet developed (evolved) to a point that allowed mankind to stand upright and do what we now do.

“I am willing to bet there are beings out there that we wouldn’t even recognize as sentient ”
Sentient is subjective. Not knowing or seeing it different then what you are accustom to. If that is true, I bet you they would be more common to us then you might think. What you want to call sentient I would call aesthetics. Like asians having slanted eyes, or people of color.

Otherwise, it is just science fiction. My opinion.

A “proper living environment” is not necessarily one that’s water and carbon based. There are several hypothetical types of biochemistry which might support life in some form.

Even so, if I were to stipulate that point and allow that all extra-terrestrial life must be water and carbon based, then I’d still seriously doubt that intelligent life formed there would necessarily be humanoid in appearance. Heck, they need not even have a bilateral symmetry.

And while sentience might be up to semantics and interpretation at some levels, I don’t think I go so far as to call it a simple aesthetic.

And finally, of course this discussion is “just science fiction”. Kinda the point, really.

“hypothetical types of biochemistry”

Right.

this discussion is “just science fiction”

Does not have to be.

It is generally accepted that our hands played a crucial role in the development of our intelligence.
So in my estimation, any species at or beyond of our level of intelligence can only get there with a viable means of detail environment manipulation, e.g. they need something analogous to hands. Unless they live in a zero G or aquatic (doubtful, underwater you make electric experiments only once, fire is also next to impossible), they will have legs.
Human level intelligence also requires a central nervous system and a capable central data processing organ, e.g. a brain. It is evolutionary probable, if not inevitable, that the major sensory organs are close to the brain united in one structure, aka, head.

In my opinion, no matter the environmental details or the biochemical makeup, the overall requirements for sapience are pretty much universal, so the evolutionary path will likely lead to similar results, e.g. a roughly humanoid appearance.

Isn’t it possible that the life on other planets is even more different from us, and they need different things to survive and have adapted to totally different living conditions? For example, everyone talks about how if there is no water found on a planet, there can’t be life, but maybe these beings don’t need water?

What they would look like would depend on where they were from and what that environment was like

I Choose to believe they all look like Keely Hazell and am therefore more than willing to submit to our new alien overlords.

(I realize it’s ridiculous o assume aliens might look like this yumeh woman.. but since this question started out with ridiculous assumptions like opposable thumbs and bipeds and aliens looking like us using no viable basis for making said assumption i figured it was ok to post a picture of a hot girl).

One things seems clear: sentience requires order and a lot of energy. Aliens won’t look like fog drifting in space.

I think whatever conditions they lived in…whatever planet they came from they were built to survive and thrive upon what ‘nature’ had given them…like us!