Extra-Terrestrial Questions

Do you believe life forms other than the ones found on Earth exist? Assuming they do, are they intelligent? Sentient? If so, do you believe them to be similar to ourselves? Hominid? Or would they be totally alien in form and psychology?

If all those are answered in the affirmative, would you postulate that they are capable of technology and industry similar to our own? And if so, do you believe ourselves capable of ever communicating with them in any meaningful fashion, either face to face or over interstellar distances?

Sorry if this topic’s come up recently… I searched it and didn’t see a similar topic anywhere within the past few months.

I believe both extraterrestrial life and extraterrestrial intelligence are possible, and extraterrestrial life is even likely. So far, there’s no evidence to actually demonstrate the existence of either.

If there are intelligent extraterrestrials, then they would almost certainly not be “hominid”. For one thing, “hominid” and other taxonomic terms like “mammalian” really mean “descendants of a specific common ancestor”, so looking for “hominids” in outer space is a bit like looking for “Buckners” in outer space. I also really doubt that the basic humanoid form is all that cosmically signicant. We are the products of a highly specific series of basically random events over millions and millions of years; intelligent extraterrestrials would be far less closely related to us than an octopus is to an elephant–in fact, they probably wouldn’t be related to us at all, unless the “panspermia” hypothesis is correct–and there’s no reason to think they’d bear any closer physical resemblance to us than a pachyderm does to a cephalopod, and maybe less. How much they’d be like us psychologically is an interesting question. We might hypothesize that all living things would need certain basic drives to survive–avoidance of danger (“fear”), when necessary actively combatting other lifeforms which pose a threat to one’s survival (“anger”), a desire to reproduce (“lust”), a need to know about one’s environment (“curiosity”). But these basic drives can be expressed in a lot of different ways; and any creature which doesn’t form long-term pair bonds in order to raise offspring in the context of bisexual reproduction might have emotional drives that would be very different from our familiar mammalian ones. And then there are things like “humor” or “music” where we don’t really understand very well why we have these traits, so it’s anybody’s guess if extraterrestrials from a completely different line of evolution would have anything like them.

There’s likely to be a wealth of different forms of life throughout the universe, including numerous sentient ones.

Of course, that is simply when discussing the nature of life as we know it.

As for communicating - well, who says some people do not? :wink:

A very serious point, though - a common and weak dismissal of sentient alien life claims that if there were any out there, why haven’t they said hello? To which the simplest reply would be - “because they’re not f***ing stupid.”

I think it’s virtually a certainty that life (maybe not organic life) has evolved elsewhere in the univerese, but communication and/or contact would still be very difficult to achieve. Given the tremendous vastness of space, it would take hundreds or thousands of years to travel between all but the very closest stars, even at the speed of light. This would make remote communication close to impossible and interstellar travel even more so.

Why would saying hello to us humans be “f***ing stupid?”

Any civilisation which can reach our solar system would surely have little to fear from us.

Try playing around with the [ulr=“http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html”]Drake Equation calculator. Drake Equation is a guideline for estinating the number of civilizations in a galaxy.

Sorry, here’s the correct link.

At first glance, ET life seems almost certain. We do, however, have one test case that appears to come up negative. As far as we know, life only emerged once on Earth. Given the long time in which Earth was “life forming friendly” doesn’t it seem odd that different forms of life didn’t come into being? Of course it’s entirely possible that this DID happen, but we don’t have any evidence that it did. As far as we can tell, all life on Earth is descended from the same life forming event.

Anyway, this has me thinking that the formation of life is not as easy as is often thought. On the other hand, there are a LOT of solar systems out there. Haven’t seen the Blake eq for awhile, but I know there is a term for probability of life getting started. I’d tend to put that a lot lower than most folks, based on the thoughts above.

I suppose in xenobiology, we’re going to have to come up with a taxonomic term greater than kingdom…call it “empire”…to describe all life that is phylogenetically related. We have good reason to believe that all life on earth is a member of the empire Terrae, since all earth life shares the same basic physiochemical makeup. Perhaps microbes on Mars are members of the same empire, perhaps they are not. It may be that all life we discover in this galaxy is a member of the same empire, all planets were seeded with bacteria from a common source.

But let’s stick to the hypothesis that life typically arises on a planet by abiogenesis. It seems to me that it is possible that life arose on earth more than once, which would mean that there would be several empires of organisms. But life arose on earth very quickly after the earth’s crust cooled enough to allow liquid water. The first empire to evolve would have a tremendous advantage, and would quickly invade all habitable areas. And that means it is curtains for any other abiogenesis, since the protobacteria from the first one are almost certain to eat the raw materials that might have started the second one.

It seems to me (keeping in mind we have a sample size of one) that since life arose very very quickly on earth, it is likely that it would also arise on any suitable body. Any place with liquid water, abundent carbon, hydrogen, oxygen and nitrogen, and some form of abundent energy (solar, geochemical, or other) is also likely to have life.

But what kind of life? For about 2 billion years the only life forms on earth were prokaryotes…bacteria of one form or another. Then we have another billion years of unicellular eukaryotes, one celled protozoans and algae. It is only in the last 650 million years that we have multicellular animals.

If we imagine that all planets with liquid water follow the same distribution, then about 10% will be lifeless, 50% will have bacteria only, 30% will have protozoans and algae, and 10% will have multicellular animals and plants. And of course, humans have only been around for several million years. But up until 120,000 years ago humans were just another species of large mammal. Succesful and interesting, yes, but not ecologically significant like fully modern Homo sapiens. I imagine that lots of animals could be considered about as intelligent and interesting, such as whales, dolphins, elephants, parrots, etc. Suppose that planets follow a similar distribuition, that would mean that intelligent life would be found on, say, 10 percent of those planets with metazoans, and tool using civilized life on 1% of those. That means 1% of planets with life having “intelligent” life that maybe you could learn to talk to, and 1% of those intelligent creatures being technological and civilized.

That means there’s a lot of algae out there in the universe, but not many human-like aliens.

Is multi-celled life that easy to evolve? If so, why did it take so long?

**mooka - **

Why? That would be extremely stupid. We’re still an agressive monkey not long out of the trees. There is everything to fear from humanity. If you don;t believe me, I suggest you take a look at the world.

If it took so long, why do you think it was so easy?



I suggest you watch War of the Worlds, or the 1996 remake with Will Smith, Independence Day. Except forget about viruses, computer viruses or F-18s coming to the rescue at the last minute. Our most advanced military would be as likely to defeat extra-terrestrial aliens as a Roman legion would be able to defeat a modern mechanised brigade.

I also don’t believe that an alien race would necessarily be benevolent. Earth history has shown us that when an advanced civilization encounters a more primitive one, the less advanced race gets the short end of the stick. All one has to do is look at a group of UFO nuts looking to the skys with their X-Files shirts and tinfoil hats and you can imagine the Incas greeting the white Conquistador “gods” who landed on their shore.

Ward and Brownlee, in their book Rare Earth (2000), have a few problems with the Drake equation, and they tinker with it some. Besides Drake’s factors, they believe you have to factor in such things as:

rockiness of the planet (essential for getting heavier-than-hydrogen elements for forming life)

existence of a Jupiter-Saturn-Mars-Moon complex of “asteroid shields” (if it weren’t for their gravity attracting a lot of space wanderers, we’d get hit a lot more often)

position of sun in the galaxy (too far from center, can 't coalesce into planets; too close to center, get hit, fried, etc.)

Their “improved” Drake equation came out with a much lower number.

They believe that life almost certainly exists elsewhere, but complex life is rare. “There is no Star Wars bar,” they said on Nightline.


When I asked about the idea of intelligent alien life being hominid, I should have said humanoid instead. I didn’t mean to imply that they’d actually be related to us since I don’t put much creedence in panspermia theories other than the possibility that multiple planets in the same solar system may’ve been seeded by a comet. Interstellar distances are just too huge for my mind to comprehend and thusly, I find it impossible to believe that humans may be related to some species of life found orbiting Alpha, Beta, or Proxima Centauri.

Aside from that, I do agree with you that I don’t believe the hominid shape to be universal in any regard but I suffer from a lack of imagination and can’t really think of how much good a sentient pachyderm could do 'cause of the inherent limits of its bodies. For instance, if we didn’t have our arms and hands free (with our handy-dandy opposable thumbs), we wouldn’t be an industrial society and thus, unremarkable when compared to any other species on earth, right?

Correct me if I’m wrong. Well, I know someone will… that comment was a bit superfluos.

My problem with the Drake equation has always been the presence of a single WAG in any equation turns the whole thing into a WAG. I am sure this has been discussed ad nauseam so I’ll keep this brief. We have no evidence of life outside of our own solar system.

Do I think life exists elsewhere? Yep.

Is that belief based on any evidence? Nope.

Somewhat of a hijack here, but…

I’m somewhat baffled by the large number of people who believe ETs exist and the large number of people who do not accept evolution (at least as it applies to humans). Seems to me it would be very difficult to hold both views at the same time (believe in ETs but no in evolution). I wonder what the affect on religions would be if life were discovered on other planets. I guess people find it easy to believe that God created life throughout the universe, and not just on Earth.

**Aesiron - **

Try the term “bipedal” instead - more flexible.

As for the equations - so riddled with baseless assumptions they really are not worth taking seriously at all.

Um, yeah. Good point, I, Brian. Thanks.