Do you believe that intelligent life exists outside of Earth?

[Yazman]

If you believe that they have visited earth or that they are among us, what do you base this belief on? What evidence, events, or witnesses would you cite?

If you believe we are alone - why?

If you believe we are the only sapient life - why?

I do not hold a concrete view on this but I am willing to take a look at any evidence that all parties present to support their views, although I lean towards the view that there is life, but we have not encountered it yet. The likelihood of environments existing that can support even basic forms of life seems to be increasing the more we develop our knowledge of other planets in the galaxy and their environments, particularly as we seem to be finding ice and liquid water. Given the nature of many of Earth's extremophiles and how many exoplanets we seem to be finding, I think it is entirely possible that sapient life may have developed somewhere else in the galaxy.

[Coggeh]

I do believe their is life out there in some form or way .I cite logic really , that the sheer size of our universe etc their would have to be some life forms .

I think it'll be a very long time until we have proof of life out there ,so in a sum up i believe their is and we haven't encountered it yet .

As for the alien conspiracy stuff , load of crap .

[ZeroNowhere]

I don't. However, I'm not 'unsure' about whether I believe in it or not, and nor do I believe that we are alone in the universe. So yeah.

[Yazman]

I don't understand your view Zero.. you don't, but you don't believe we are alone? I don't get it?

[Rosa Lichtenstein]

Yes, but I am only visiting.

[MMIKEYJ]

There has to be other life out there... There is plenty of evidence that we've been visited in the near past and ancient past, and currently are being visited as well.

In all likelihood they are walking amongst us now, even as we speak.

[Elect Marx]

I am fairly sure that life is statistically probable, considering even the likelihood that similar lifeforms to us can form or spread by planetary seeding.

Self-awareness and higher intelligence seem to be only a matter of time in any effort to regularly adapt to a changing environment. The main obstacle I see, is how highly intelligent lifeforms can so easily use technology to destroy themselves.

[ÑóẊîöʼn]

Considering the huge variety of habitats that Earthly life inhabits, the massive number of potentially life-bearing worlds, and the possibility of life taking forms other than solid carbon-based forms (Alien lifeforms could be plastic, liquid or gaseous, and could be based on non-carbon chemistry or even more exotic stuff such as hot or cold plasmas, neutron star matter or natural "electronic" life in pools of liquid helium), I think the discovery of extraterrestrial life is simply a matter of time. However, we may be waiting a long time.

As for ancient astronaut theories and the idea that aliens are currently among us, such ideas are not only completely lacking in evidence, but display a shocking degree of anthropocentrism - why the fuck would a species capable of crossing interstellar distances bother itself with a bunch of squishy ape-things that have yet to expand beyond the confines of their native planet?

Protip to the conspiracy nuts: believe it or not, the universe and it's contents do not exist for the benefit of human beings, or any other sapient species that happens to be around for that matter.

Grey aliens? Give me a fucking break. Whatever intelligent aliens will look like, they won't look like some loser in a cheap Halloween costume. I could go into a huge rant about the intellectual and imaginative bankruptcy of alien conspiracy believers and Hollywood, but maybe I'll save that for another time. Let's just say that even real life ecosystems display more morphological diversity than the likes of Star Trek et al.

[Dr Mindbender]

At the very least, if not intelligence, there has to be life elsewhere.

The laws of logic and probability dictate this. The fact that we have 2 neighbouring planets in our solar system (Earth and Mars) that possibly both host life suggests that the universe must be absolutely teeming with life.

I think it will take us longer to find intelligence but if i was a betting man i'd put money on it existing.

[Some Red Guy]

Yes. Considering the size of the univere there has to be life somewhere else. I belive the existance of extraterrestrials is pretty much beyond doubt.
When it comes to aliens on earth, I've done a lot of reading on the subject. NoXion makes good points in his post but I still believe there could have been ET's to this planet. Not unthinkable and not impossible. Unlikely, yes, but many unlikely things have happened before. I heard the Soviet government was heavily into UFO research as well. On the whole "how did they get here", I found an interesting article.
I can't post links, but google "UFOs: Challenge to SETI Specialists"
After the revolution we will probably know the truth, whatever it may be.

[Dean]

The third option was the only rational one, because it didn't include absolutes.

[Led Zeppelin]

I don't understand your view Zero.. you don't, but you don't believe we are alone? I don't get it?

I think he meant that he doesn't believe in intelligent life existing, but simply life.


The third option was the only rational one, because it didn't include absolutes.

Haha, that reminds me of that scene from Star Wars; "Only a Sith deals in absolutes!"

[WhitemageofDOOM]

Are there other life bearing planets in the universe? Almost certainly.
Are there other animals that can be called people? Almost certainly.

Will we ever meet them? HAAHAHAAHAHAAHAHAHAHA, no. The distances and possible travel speeds are simply too much of a barrier.

[Tzonteyotl]

Are there other life bearing planets in the universe? Almost certainly.
Are there other animals that can be called people? Almost certainly.

Will we ever meet them? HAAHAHAAHAHAAHAHAHAHA, no. The distances and possible travel speeds are simply too much of a barrier.

Ah, but you see, that's where wormholes come in. And Infinite Improbability Drives and...

[Tzonteyotl]

As far as the original question, I'd have to say it is probable that there are other intelligent lifeforms out there. Not just because of the size of the universe, but also because of its age. Given that the Earth is only 4.5 billion years old and we've evolved in that period from previous lifeforms, if life began earlier on older planets (the universe being about 14 billion years old) that's more than enough time for intelligent life to evolve, assuming conditions remained favorable to whatever life there was and allowed for its continued evolution. In any case, I didn't actually vote in the poll as I felt there should be an option saying that yes, intelligent life is probable, but that it's unsure as to whether we'll ever make contact.

[ÑóẊîöʼn]

Ah, but you see, that's where wormholes come in. And Infinite Improbability Drives and...

No need for that, we can colonise the universe at sublight speeds. It'll just take us a very long time...

[Glorious Union]

I think that it is very possible that lein life has visited earth before, after all, we are only in our what is it now, four thousandth year? And the Earth has been around for a few billion years. That deffinately enough time for a sentient species to find space travel and visit Earth. But I don't beleive they walk among us, thats just ridiculous.

[Dooga Aetrus Blackrazor]

This topic is a joke. I haven't posted here in awhile, but, wow. No wonder people think leftists are delusional. There is no compelling evidence for life outside of Earth. An overwhelming majority of scientists know this. Even "IF" you think there "COULD" be intelligent life outside Earth, there is a big difference in believing in possibility and believing in fact.

If that many of you honestly "believe" in intelligent life outside Earth, you need to come back to reality.

[Blackscare]

This topic is a joke. I haven't posted here in awhile, but, wow. No wonder people think leftists are delusional. There is no compelling evidence for life outside of Earth. An overwhelming majority of scientists know this. Even "IF" you think there "COULD" be intelligent life outside Earth, there is a big difference in believing in possibility and believing in fact.

If that many of you honestly "believe" in intelligent life outside Earth, you need to come back to reality.


Why is it so unlikely? Most people on here aren't saying that they're walking among us (ok, well one did).

What reason do we have to believe that in such a massive universe that is as old as it is, there isn't life similar to our own out there?

Why couldn't intelligent life arise somewhere else?

Most people accept it as fact because given the size of the universe, mathematically it is very, very likely that somewhere else the factors required for life as we know it to form would come together into a habitable planet. No one here is saying "Yes, I KNOW THEY EXIST, AND I'LL TELL YOU WHAT PLANET THEY'RE ON".

It seems pretty reasonable to me to assume intelligent life is somewhere else in the universe at this very moment, to believe otherwise is to be completely arrogant and egotistical. What makes us so god damned special? Certainly not some invisible man in the sky, if that's where you're getting these silly ideas from.

[Blackscare]

There is obviously no direct evidence, but we've only been looking for a short time, and we're not sure exactly what to look for. Who knows what methods they would use to communicate, maybe we're not looking at the right types of signals with SETI?

From logic we can infer that there is most likely life like us somewhere else in the universe. Your argument seems a lot like the "flat earthers" from back in the day. "If the world is round, why is the ground flat? Ha, I got you! The direct evidence isn't there!".

[revolution inaction]

This topic is a joke. I haven't posted here in awhile, but, wow. No wonder people think leftists are delusional. There is no compelling evidence for life outside of Earth. An overwhelming majority of scientists know this. Even "IF" you think there "COULD" be intelligent life outside Earth, there is a big difference in believing in possibility and believing in fact.

If that many of you honestly "believe" in intelligent life outside Earth, you need to come back to reality.

It's far more probable that intelligent life exists some where else than that there is no intelligent life except on earth so it is not unreasonable to believe it exists.

[Lord Testicles]

The Drake Equation (http://www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/alone/drake/)

[ÑóẊîöʼn]

The Drake Equation (http://www.bbc.co.uk/sn/tvradio/programmes/horizon/broadband/tx/alone/drake/)

The problem with the Drake Equation is that we have no idea what most of the variables should be - average rate of star formation is the only one we can be fairly sure of.

We can only observe really large extrasolar planets (although that may change in the future) and gas giants don't seem like good candidates for multicellular life, let alone civilisations.

The other numbers are pure speculation since we only have one sample (our solar system) and there's no way of telling how representative it is, if at all.

For all we know, the galaxy could be teeming with life, but we simply can't (currently) observe it due to the sheer distances involved. Perhaps intelligent life is also common, but the vast majority of it never leaves their homeworld or can't, won't, or doesn't communicate* at interstellar distances.

Also, on the subject of TV signals - because they're subject to the inverse-square law, any of our accidental transmissions are likely to be overwhelmed by universal background noise before it reaches any meaningful distance. Space is huuuuuuuge.

*By this I include actual travel as well as sending signals.

[synthesis]

I think there is an important distinction that must be made between conditions that can support life and conditions that can create life. Obviously, the criteria for creating life is much more specific, which leads me to doubt that extraterrestrial life is particularly common, even given the enormity of the universe. That is, unless you subscribe to the panspermia hypothesis, which doesn't seem particularly well-evidenced at this point.

[ÑóẊîöʼn]

I think there is an important distinction that must be made between conditions that can support life and conditions that can create life. Obviously, the criteria for creating life is much more specific, which leads me to doubt that extraterrestrial life is particularly common, even given the enormity of the universe.

The thing is, life only needs to arise once. Given billions of years, and billions of potential sites in our galaxy alone, that's more than enough chances for life to arise even if it's astoundingly rare for it to do so.

But of course, getting an exact fix on the odds would help enormously. Experiments into abiogenesis will hopefully provide some clues at least.

[Vendetta]

I think life almost certainly does exist, but whether it's intelligent remains to be seen.

[apathy maybe]

I don't know / have yet to form an opinion

Except, that I have formed an opinion, the opinion is that we can't know at this stage whether life exists outside our solar system. I would suggest that it is possible, or even probable, but: "I try not to think with my gut. Really, it's okay to reserve judgement until the evidence is in."

And the fact is, we don't have any real evidence. (But at least life on other planets is logically possible, unlike god.)

[Rangi]

Does intelligent life exist in outer space? Maybe. Does it exist on Earth?

[Dr Mindbender]

Does intelligent life exist in outer space? Maybe. Does it exist on Earth?

The scientific definition of 'intelligent life' is any species with the ability to both send and recieve radio signals. So the scientific answer is yes.

[NecroCommie]

Even if there were aliens, why would they ever come here? All they would see is dinosaurs since light only travels so fast. We can propably be seen in just a few star systems.

[ÑóẊîöʼn]

The scientific definition of 'intelligent life' is any species with the ability to both send and recieve radio signals.

Since when? By that definition, we weren't intelligent before 1879.

[Dr Mindbender]

Since when? By that definition, we weren't intelligent before 1879.


http://astrobiology.nasa.gov/ask-an-astrobiologist/question/?id=918




Question


What is the definition of intelligent life? Is it the abilty to analyze situations and react in the correct way, or is the complexity the primary issue?

This is a diffficult question, and I have never found a satisfactory answer. This question is sometimes addressed in books and articles on SETI (for example, in "Extraterrestrials: Science and Alien Intelligence", edited by Edward Regis, Cambridge University Press, 1985), but from the SETI perspective intelligence must include the ablity to transmit and receive signals over interstellar distances (that is, technological intelligence). More generally, Carl Sagan wrote (in "Cosmic Connection," recently reprinted by Cambridge University Press) that intelligence involves the tendency toward control of the environment -- including a non-hereditary adaptive quality developed during the lifetime of a single individual (that is, intelligent creatures can learn). Other more recent definitions have been suggested by those working in the field of artificial intelligence. Good luck with this pursuit!

David Morrison
NAI Senior Scientist
May 6, 2004

[Led Zeppelin]

I know I'm merely pointing out the obvious, but "the SETI perspective" does not equal "the scientific definition of intelligent life".

[Dr Mindbender]

I know I'm merely pointing out the obvious, but "the SETI perspective" does not equal "the scientific definition of intelligent life".

The NASA guy said he did'nt know of another definition so it's all we've got. Besides which SETI are an authority on the subject so i think i'll go along with them, thanks.

Otherwise we're just going by people's subjective opinions.

People would argue that animals are intelligent because they don't start wars. When was the last time you saw a cat playing sodoku?

[ÑóẊîöʼn]

The NASA guy said he did'nt know of another definition so it's all we've got. Besides which SETI are an authority on the subject so i think i'll go along with them, thanks.

Otherwise we're just going by people's subjective opinions.

The question of sapience is not subjective, it's merely limited to the invention of radio in the SETI instance because of the technological limitations of SETI - it wouldn't be able to detect the equivalent of an Iron Age civilisation, the known examples of which (Human) are other defined as intelligent.

[Dr Mindbender]

The question of sapience is not subjective, it's merely limited to the invention of radio in the SETI instance because of the technological limitations of SETI - it wouldn't be able to detect the equivalent of an Iron Age civilisation, the known examples of which (Human) are other defined as intelligent.


If there are species with iron age levels of development, they are irrelevant because we cant communicate with them.

SETI is only interested in species that can reply to us.

[Decolonize The Left]

I'm with NoXion on this one. The universe is simply too large, and there are simply too many possible scenarios through which life could emerge, I don't see how one could hold onto the extremely small probability that there isn't life outside of our planet as truth...

- August

[synthesis]

The thing is, life only needs to arise once. Given billions of years, and billions of potential sites in our galaxy alone, that's more than enough chances for life to arise even if it's astoundingly rare for it to do so.

But of course, getting an exact fix on the odds would help enormously. Experiments into abiogenesis will hopefully provide some clues at least.

I would disagree with your assertion that life only needs one chance. Even if abiogenesis was a common occurrence, the number of variables involved in the process indicates that it is far more likely for organic matter to either be destroyed or dissolved into its constituent parts. I hate to quote Wikipedia, but I think this is relevant.

"The spontaneous formation of complex polymers (http://en.wikipedia.org/wiki/Polymer) from abiotically generated monomers under the conditions posited by the "soup" theory is not at all a straightforward process. Besides the necessary basic organic monomers, compounds that would have prohibited the formation of polymers were formed in high concentration during the Miller-Urey and Oró experiments. The Miller experiment, for example, produces many substances that would undergo cross-reactions with the amino acids or terminate the peptide chain.

More fundamentally, it can be argued that the most crucial challenge unanswered by this theory is how the relatively simple organic building blocks polymerise and form more complex structures, interacting in consistent ways to form a protocell. For example, in an aqueous environment hydrolysis (http://en.wikipedia.org/wiki/Hydrolysis) of oligomers/polymers into their constituent monomers would be favored over the condensation of individual monomers into polymers."

[Dooga Aetrus Blackrazor]

Why is it so unlikely? Most people on here aren't saying that they're walking among us (ok, well one did).

What reason do we have to believe that in such a massive universe that is as old as it is, there isn't life similar to our own out there?

Why couldn't intelligent life arise somewhere else?

Most people accept it as fact because given the size of the universe, mathematically it is very, very likely that somewhere else the factors required for life as we know it to form would come together into a habitable planet. No one here is saying "Yes, I KNOW THEY EXIST, AND I'LL TELL YOU WHAT PLANET THEY'RE ON".

It seems pretty reasonable to me to assume intelligent life is somewhere else in the universe at this very moment, to believe otherwise is to be completely arrogant and egotistical. What makes us so god damned special? Certainly not some invisible man in the sky, if that's where you're getting these silly ideas from.

The universe is so big that intelligent life must exist? That is a terrible argument. You could say the same thing about God - and people do. The fact is that intelligent life exists at all was statistically unlikely. You're taking a low probability and multiplying it for every instance of intelligent life. It's the equivalent of taking a deck of a million different cards. Intelligent life is one card in that deck. The chance you you drawing the same card twice increases given factors of time and space.

Essentially, you are saying the universe is so vast that it is a likely probability that intelligent life exists. Firstly, all you "believers" have no idea the size of the universe relative to the probability of intelligent life existing (well, maybe a few of you do). If you don't know the probabilities, the default position on existence if nonexistence.

If you do no the probabilities (which some scientists feel you can), you will conclude that it is unlikely intelligent life exists elsewhere. My astronomy professor told me straight up that the majority of scientists don't believe in intelligent life. NASA just uses it as an excuse for funding (because gullible people fall for it).

[More Fire for the People]

Yes, and they probably exist within 100 light years.

[Revolutionary Youth]

Maybe some of them out there on other solar system are sitting in front of their "computer" (or whatever they call it!) and posting on their forum on this matter too!:D

[WhitemageofDOOM]

Essentially, you are saying the universe is so vast that it is a likely probability that intelligent life exists. Firstly, all you "believers" have no idea the size of the universe relative to the probability of intelligent life existing (well, maybe a few of you do). If you don't know the probabilities, the default position on existence if nonexistence.

If you do no the probabilities (which some scientists feel you can), you will conclude that it is unlikely intelligent life exists elsewhere.

The observable universe alone has around 100billion galaxies and is 14.8 billion light years in size. -Observable-, the universe is likely far far larger.
It's true we can't know the possibilities of life, we do however know that intelligent life is possible. And anything possible given enough time and space becomes inevitable.
It is not from logic you reach your conclusions but egocentrism. What makes you think humans are so special?

For instance, we know it is possible for air to turn into gold. We have never seen this, to conclude then air can't turn into gold would be intellectually dishonest. The facts clearly state it can, it's just very very very very very very very unlikely. But stupidly unlikely things are still inevitable given enough chances of happening.

[Boy Named Crow]

My opinion is I think that it would be incredibly self-important of us to assume that we are the only life in all of space.

Odds are that there's another rock out there in some back-water of the universe with some form of life on it.

I voted "don't know" simply because thats the truth - I don't know, but logically there could be.:confused:

[Boy Named Crow]

But stupidly unlikely things are still inevitable given enough chances of happening.

"Million To One chances actually happen nine times out of ten..."

Terry Pratchett

love that quote!

[Dooga Aetrus Blackrazor]

The observable universe alone has around 100billion galaxies and is 14.8 billion light years in size. -Observable-, the universe is likely far far larger.
It's true we can't know the possibilities of life, we do however know that intelligent life is possible. And anything possible given enough time and space becomes inevitable.
It is not from logic you reach your conclusions but egocentrism. What makes you think humans are so special?

For instance, we know it is possible for air to turn into gold. We have never seen this, to conclude then air can't turn into gold would be intellectually dishonest. The facts clearly state it can, it's just very very very very very very very unlikely. But stupidly unlikely things are still inevitable given enough chances of happening.

I don't think humans are special, but it is logic. You completely missed my point.

P1: If we don't know the probabilities concerning the origin of life, we can't assume the existence or nonexistence of other entities.
P2: If we do know the probabilities of life (which some scientists claim), the probabilities seem to indicate other intelligent life is not probable (few scientists actually believe in it).
P3: Scientists are the best qualified to judge information regarding the existence of other life forms.
P4: In cases where the existence of an unknown entity has no data either for or against it, the default logical position is to believe in nonexistence.
Conclusion: Either (1) we believe in nonexistence of alternative life based on an absence of information (we aren't disregarding the possibility, just the actual belief, or (2) we take the information available concerning the issue to be accurate and we believe other intelligent life does not exist.

The information that intelligent life exists outside humanity is just not there in comparison to information to the contrary. If you want to say it is possible, that is completely legitimate. Belief is "NOT." Belief is an active position in which you accept something to be true based on the information available. It is not an intellectually credible position to "believe" in alternative life forms.

[Yazman]

Debating "belief" or not is irrelevant... and its kind of beside the point, although I appreciate what you're saying. Would it make a difference to you if the word "belief" in the question was swapped with "think"? Because that is really what its getting at anyway.

[Dooga Aetrus Blackrazor]

Debating "belief" or not is irrelevant... and its kind of beside the point, although I appreciate what you're saying. Would it make a difference to you if the word "belief" in the question was swapped with "think"? Because that is really what its getting at anyway.

Think is kind of the same thing. It would make a difference if it was swapped with "do you believe it's possible ... exists."

[Vahanian]

yeah i think that there are aliens out there. because if were the only intelligent life in the universe were screwed.:lol:

[redSHARP]

Mad magazine did a great cartoon about aliens landing on earth. they try to invade but see all the crime, drugs, pollution, and violence; they run away scared!:laugh:

[The Author]

Do you believe that intelligent/sapient life exists outside of earth?

Well, why not?

I mean, am I to sincerely believe that out of the billions and billions of galaxies and stars in the universe, our planet is the only world inhabited by life?! The notion sounds ridiculous!

[synthesis]

Well, why not?

I mean, am I to sincerely believe that out of the billions and billions of galaxies and stars in the universe, our planet is the only world inhabited by life?! The notion sounds ridiculous!

The universe is big, but it's not infinite. It might sound ridiculous to you, but until you have any kind of grasp on the actual probabilities of intelligent life randomly developing on a big hunk of space rock, it would be wise to refrain from judging one way or another.

In other words, if there are a trillion planets in the universe, we might find that the chances of a planet catalyzing, molding and supporting intelligent life are one in a hundred trillion. We just don't know. It doesn't seem that likely to me, but who can tell?

[mikelepore]

We are products of a long sequence of one-in-a-million chances. The rarity of liquid water is often discussed, but there's a lot more. One big factor, there were many mass extinction events, but instead of wiping our our niche, they all happened at the right moments to wipe out other animals to make the room for our niche. That's incredible luck.

[benhur]

How is life formed anyway?

[Yazman]

We are products of a long sequence of one-in-a-million chances. The rarity of liquid water is often discussed, but there's a lot more. One big factor, there were many mass extinction events, but instead of wiping our our niche, they all happened at the right moments to wipe out other animals to make the room for our niche. That's incredible luck.

I hate when people describe it as "all up to chance" or a result of "incredible luck" that we are here today or that life arose. Seems pretty shortsighted to describe it in that manner.

[ÑóẊîöʼn]

I hate when people describe it as "all up to chance" or a result of "incredible luck" that we are here today or that life arose. Seems pretty shortsighted to describe it in that manner.

It's also wrong. Evolution is not a matter of chance - in fact, it's the opposite.

[mikelepore]

I reommend the book 'Rare Earth' by Ward and Brownlee for a good introduction to the subject. A very long list of luck factors made life possible here.

If the earth had more mass it might have interfered with the appearance and survival of large animals, but if it had less mass its atmosphere could escape. If Jupiter had less mass it could have been unable to attract most of the solar system's asteroids that kept crossing the earth's path, but if Jupiter had more mass it could have interrfered with the formation of the rocky planets or the stability of their orbits. If we had less water, which fortunately came to earth due to comet collisions, the solvent in which life occurs might not be sufficiently available, but if we had more water we wouldn't have had the shallow water regions needed for limestone to remove carbon dioxide from the atmosphere. There are a whole lot of just-right probabilities multiplied together.

If the earth's orbit were a more eccentric ellipse, or if were had a pulsing star, the earth would have more extreme hot and cold periods. If we didn't have the right amount of vulcanism to produce a sufficiently strong but relatively steady magnetic field, cosmic rays would sterilize the planet. If the collision with the twin planet that produced the moon had happened later than it did, the remelting of the earth's surface might have occurred after the appearance of life and not before. If we were on a planet with tidal lock, one side facing the sun permanently, the world would have one extremely hot hemisphere and one extremely cold hemisphere. If the event that caused the Permian extinction, now believed by many astronomers to be a gamma ray burst, had happened later, we might have been in the middle of that extinction of ninety percent of the species on the earth.

[ÑóẊîöʼn]

I reommend the book 'Rare Earth' by Ward and Brownlee for a good introduction to the subject. A very long list of luck factors made life possible here.

Why should Earth-like life be the default? It evolved for the specific conditions of the Earth, which may indeed be unique. But life elsewhere will have evolved for conditions there, which will in all likelyhood be different.


If the earth had more mass it might have interfered with the appearance and survival of large animals, but if it had less mass its atmosphere could escape.More mass would simply have meant that natural selection would favour smaller, lighter animals. As for losing atmosphere, that's not a problem as long as biological and/or geological processes can replace it sufficiently. Free hydrogen currently escapes the Earth's atmosphere because it is so light - a sufficiently reactive gas denser than oxygen, such as flourine, could make for an "alternative" to oxygen on lower-mass planets.


If Jupiter had less mass it could have been unable to attract most of the solar system's asteroids that kept crossing the earth's path, but if Jupiter had more mass it could have interrfered with the formation of the rocky planets or the stability of their orbits.Obervations of extrasolar planets have indicated that large gas giants are common. Of course, due to instrumental limitations our results are biased towards systems with gas giants close to their stellar primary - but of course, an instrumental limitation is not a reflection of reality.

There are two questions that need to be answered, which are "how many asteroid impacts are too much?" and "how big can gas giants get, and what is the lower limit of the mass of a gas giant that is significantly likely to affect rocky planet formation?"

Answer those two questions, as well as getting a general idea of what a typical solar system looks like (which we do not have at the moment), and we will be significantly closer to answering the question of how common life is in our galaxy.


If we had less water, which fortunately came to earth due to comet collisions, the solvent in which life occurs might not be sufficiently available, but if we had more water we wouldn't have had the shallow water regions needed for limestone to remove carbon dioxide from the atmosphere.Water is a ridiculously common compound in the universe. Even Mars, which today is a bone-dry world, shows the signs of having possessed significant amounts of water. It's not a matter of getting it, it's a matter of holding on to it.

As for having "too much" water, CO2 sequestration in limestone (which is a by-product of life, by the way), is not the only way of getting rid of carbon dioxide - why do you think Earth has significant amounts of oxygen in it's atmosphere in the first place?


There are a whole lot of just-right probabilities multiplied together. Nonsense. Most so-called "just-right" probabilities are arguments from ignorance based on our lack of knowledge of what a typical solar system looks like. Others are based on a failure of imagination or a failure to appreciate life's potential for diversity and adaptation.


If the earth's orbit were a more eccentric ellipse, or if were had a pulsing star, the earth would have more extreme hot and cold periods.How hot? How cold? Most stars are not variables, and highly elliptical orbits are more typical of comets, "hot jupiters" and Kuiper Belt Objects like Pluto, unlikely spots for life (as we know it) in the first place.


If we didn't have the right amount of vulcanism to produce a sufficiently strong but relatively steady magnetic field, cosmic rays would sterilize the planet.Only the surface layer. Underground, or with a sufficient depth of water, on the other hand...


If the collision with the twin planet that produced the moon had happened later than it did, the remelting of the earth's surface might have occurred after the appearance of life and not before.Such large collision events are far more likely to occur early in the formation of a solar system.


If we were on a planet with tidal lock, one side facing the sun permanently, the world would have one extremely hot hemisphere and one extremely cold hemisphere.Plus a band of habitability in the twilight zone.


If the event that caused the Permian extinction, now believed by many astronomers to be a gamma ray burst, had happened later, we might have been in the middle of that extinction of ninety percent of the species on the earth.Extinction events are setbacks for life, not endgames.

[mikelepore]

I'm not saying that life elsewhere has to be similar to life here, but the entire set of data is a sample size of 1. All life on earth uses the same method of combining the same nucleotides, which shows that all life in all kingdoms has one common ancestor. The initial appearance of life on earth occurred one time. If life was initiated on earth two or three or ten times, all but one became extinct, which is still only one success. In all the droplets of water in the world, already given the narrow range of necessary environmental conditions, and given over four billion years, it happened once.

[BlackCapital]

Absolutely. In fact I find it kind of shocking that 15 people on this forum did not have an opinion or thought no. The absolutely staggering,incomprehensible size of the Milky Way ALONE should be enough to conclude that if it has occurred here, it has/is/will occur somewhere else. Although we have no reason to believe that life can only exist under the circumstances they do here, there is a plethora of earth-like planets very close to us, and I believe NASA is about to check some of them out with Kepler. I would go as far to bet my right arm that there is single cellular or microbial life in our solar system.

To me the much more interesting question is have they visited Earth? I'm really torn on this. On one hand, I see it completely possible that a much older, more advanced civilization has mastered space-time and can easily move around it, thus being able to conquer vast distances and explore whatever they want, including inhabited planets. On the other hand, humans have existed for the blink of an eye, and have been transmitting radio signals even less, so we could just not be in the proper location in space and time to have made contact. I lean towards the former though.

[ukuli]

Certainly there is life out there in the Galaxy. But intelligent life might be very rare, and we might never find evidence of it...

[Comrade B]

The universe is infinite. To think that we are the only form of any kind of life is ridiculous and egotistical. If it is infinite, I believe that there is a world for every possible situation imaginable.

I do not though, think that contact will ever be made.

[synthesis]

The universe isn't infinite. The idea that because the universe is so vast that there must be intelligent life is pretty much a given for a few people on this forum and many others, which is amusing to me. It's basically a religious belief, an a priori assumption, a set of comforting thoughts that reassures us we really aren't alone after all.

Truth is, we don't really have any kind of handle on the probabilities of intelligent life existing out there and the funny thing is that we never really will, because of this little guy (http://en.wikipedia.org/wiki/Chaos_theory). I mean, even if we knew every variable in the Drake Equation - that is, every variable involved in creating life - we can't ever really know the opposite, meaning every variable involved in destroying life. In other words, the Drake Equation still doesn't account for these (http://en.wikipedia.org/wiki/ELE).

What if we faced the much more mind-boggling proposition, albeit the one to which we would be led by Occam's Razor? That there really is something unique about human society on this planet? That perhaps we are the only development that the universe has ever produced which is capable of consciously manipulating its surroundings, and may one day be capable of tearing a hole in its own fabric?

What if there really is something special about us? Doesn't that mean we should focus on the here and now rather than automatically assuming this can't be all that there is?

Because that sounds about right to me.

[apathy maybe]

The universe is infinite. To think that we are the only form of any kind of life is ridiculous and egotistical. If it is infinite, I believe that there is a world for every possible situation imaginable.

I do not though, think that contact will ever be made.

Umm, I used to think that it was absurd to think that the universe wasn't infinite, after all, what can exist outside everything?

Then I read about how most scientists in the relevant fields don't actually think the universe is infinite.

Then I realised I didn't have enough evidence or knowledge to make a judgement either way, and I just stopped thinking about it.


There are many parts of science that are basically inaccessible to me, I don't have a hope of providing evidence for or against, and just have to accept the word of scientists. The size of the universe is one.

As to aliens, well, that's an area where science doesn't have an answer, and can't give an answer at this time. I feel perfectly able to provide an answer though. And that answer is the same as science provides: "I don't know".

There is nothing wrong with that. We (as a collective) just don't have enough evidence to say either way. We probably never will have enough evidence to say that "aliens probably don't exist".


What if there really is something special about us? Doesn't that mean we should focus on the here and now rather than automatically assuming this can't be all that there is?
However, even if there are no aliens, it doesn't make humans special. Humans aren't special, and to say that they are (in the way that most people do, as if we create the universe we see, merely because of our existence), is just a logically flawed as saying that aliens exist.

But, just because humans aren't special (even if they are unique), doesn't mean we can't focus on there here and now.

[synthesis]

I just can't make any sense out of the proposition that humans are not special. Even if we're insignificant, it doesn't mean we are mundane. We may be the only collection of moving particles that is capable of perceiving itself as a collection of moving particles and able to consciously manipulate those particles for our own purposes. That seems special enough to me.

[Lynx]

Saying that humans are mundane is just as illogical as saying they are special. If humans are all alone in the universe, then they are unique.

[Hiero]

There are many parts of science that are basically inaccessible to me, I don't have a hope of providing evidence for or against, and just have to accept the word of scientists.

You could learn science at a university level.

[Forward Union]

I am dissapointed so many people voted for "yes. it's a matter of time"

How do you know it's a matter of time. It might not be. We might never find anything, and we'll never explore the entire universe, and will consequently never be able to say that "there is no other life". Like god, we can't prove the absence of something like that. If you truly believe there IS life in space and it's a matter of time, the only way you could be disproved would be for humans to explore every single inch of the universe, and have all of it under constant and absolute surveillance. Consequently any belief in extra terrestrial life t is essentially faith.

I'm agnostic on the matter. but recognize that there is a high possibility of life in the universe, i mean;

a) life is clealy possible, we have examples of it here

b) there is nothing supernatural about the existence of life here

c) We don't know how it started, but given the incredible scale of the universe, it's certainly possible that even the rarest circumstances may have happened twice

[Forward Union]

I just can't make any sense out of the proposition that humans are not special. Even if we're insignificant, it doesn't mean we are mundane. We may be the only collection of moving particles that is capable of perceiving itself as a collection of moving particles and able to consciously manipulate those particles for our own purposes. That seems special enough to me.

Every animal thinks it's special. Special enough to kill others and pass it's genes on. Its not surprising we have a built in condition to love ourselves. It's why people see so many faces in nature.

Objectively we're just complex physical compounds.

[synthesis]

Every animal thinks it's special.But not consciously. Non-human animals can't debate as to whether they are special or not.

special, n. Distinguished by a unique or unusual property.



Objectively we're just complex physical compounds.My opinion is that we are unique because your average complex physical compound is not capable of ascertaining its own properties. Science tells humans about the universe, but humans created science. I think that makes us "special" in some sense of the word. Perhaps I am alone in thinking this.

[Forward Union]

But not consciously. Non-human animals can't debate as to whether they are special or not.

special, n. Distinguished by a unique or unusual property.

So? we can't reproduce a-sexually so bacteria are special. We can't wag our tails, so dogs are special etc. Of course we're the most developed, intelligent, and capable species that we know of. We also have a high level of self consciousness, which other animals lack. These are measurable facts, the use of the word 'special' however, is nothing more than an emotional annotation that I don't care much about.


My opinion is that we are unique because your average complex physical compound is not capable of ascertaining its own properties. Science tells humans about the universe, but humans created science. I think that makes us "special" in some sense of the word. Perhaps I am alone in thinking this."Humans created science" is a grammatically incorrect statement and holds no meaning. The facts that science has established are not man made, they are objective and would be true whether we were here or not. The study of these things by man is what we call science, but we didn't invent that process, that would have required us to create ourselves, the universe, logic, and the process by which we establish facts.

Science is a human endeavor. Like eating, reproducing etc. We didnt invent these things.

[apathy maybe]

But not consciously. Non-human animals can't debate as to whether they are special or not.

special, n. Distinguished by a unique or unusual property.

Prove it. No one on RevLeft has yet been able to show that humans are the only animal able to think. It is constantly raised as a "fact", except that the belief is as absurd as a belief in god. Indeed, I have read many times that certain animals (including parrots, pigs, dolphins and chimpanzees) are able to distinguish themselves from others, plan for the future, work together, empathise, and many other characteristics that you might (incorrectly) think are uniquely human.

Go on, provide an article from a journal in the field that says that humans are the only animal able to debate if they are special or not.


@Hiero Maybe some people could. Heck, I could probably learn some level of some science. However, I don't feel the need, nor am I confident of my ability beyond the basics in most fields.

[DesertShark]

I agree with NoXion. The universe is too large and too old for us to be the only ones. If all the galaxies in the universe were shrunken down to pea-size, they would overflow a basketball arena. Our galaxy (Milky Way) alone is 100,000 light years across (ie traveling the speed of light it would take 100,000 years to cross). And we're just one solar system in this galaxy. I do think though that we won't run into other life given the size of everything.

The fact that we are here is not luck; I'm not going to dive into this as I think NoXion did an excellent job tackling that and evolution.

[synthesis]

The study of these things by man is what we call science, but we didn't invent that process

Uh... yeah, we did. I don't really know how you can deny that science is a human innovation. Science generally studies nature, which is not a human innovation, but the ability to study nature and formulate theories based on observations - that is purely human.

Even if science is simply a result of some evolutionary trait that engenders curiosity or something like that, that wouldn't change my opinion (which I'll explain further in the last part of this post.)


Prove it. No one on RevLeft has yet been able to show that humans are the only animal able to think. It is constantly raised as a "fact", except that the belief is as absurd as a belief in god. Indeed, I have read many times that certain animals (including parrots, pigs, dolphins and chimpanzees) are able to distinguish themselves from others, plan for the future, work together, empathise, and many other characteristics that you might (incorrectly) think are uniquely human.

Go on, provide an article from a journal in the field that says that humans are the only animal able to debate if they are special or not.

When parrots start curing diseases and exploring space, I'll take note of it. :)



Science is a human endeavor. Like eating, reproducing etc. We didnt invent these things.

Science hasn't been around forever, not the way we think of it. It took us millions of years to separate science from supernaturalism.


So? we can't reproduce a-sexually so bacteria are special. We can't wag our tails, so dogs are special etc. Of course we're the most developed, intelligent, and capable species that we know of. We also have a high level of self consciousness, which other animals lack. These are measurable facts, the use of the word 'special' however, is nothing more than an emotional annotation that I don't care much about.

You completely missed the point.

The original question asked if we think intelligent life exists outside Earth. I argued that since we don't actually have any grasp on the probabilities of intelligent life developing, and since we never will know the probabilities of that life being destroyed, then we ought to proceed as though the answer to the question is "no."

It is essentially an apatheist response to what is essentially a religious belief. The evidence is unclear, and there are no clear benefits of presupposing the existence of intelligent life, so I argue that it is best to proceed as though this is all there is.

Disregarding Occam's Razor, the idea that the universe is just packed with beings like us, or "better", is too often used to justify the conviction that what we do here just doesn't matter. In that same sense, we can get caught up in our own insignificance; too many nights gazing out into the stars does not necessarily lead one to being productive in the here and now. "This can't be all there is..."

I asked if it would not be better to appreciate the massive odds against intelligent life developing and surviving, and to instead consider the possibility that whatever it is we call "intelligence" might be exclusive to the third hunk of rock orbiting a tiny star in the middle of nowhere.

That would indeed make us special and unique; it would be the very definition of the word, at least for the purpose of this discussion, because we would be the only physical compound that possesses intelligence. If you choose to attach emotions to such a revelation, that's not my problem.

[synthesis]

Couple more things...



Go on, provide an article from a journal in the field that says that humans are the only animal able to debate if they are special or not.Er, the the burden of proof is on you here. Until you prove otherwise, the evidence I have indicates that humans are the only species capable of holding complex philosophical discussions. Asking me to prove my point is asking me to prove a negative. (And you accuse me of religious tendencies!)



The fact that we are here is not luck; I'm not going to dive into this as I think NoXion did an excellent job tackling that and evolution.Define "luck." I'd say our ancestors were "lucky" not to die along with the dinosaurs.


The universe is too large and too old for us to be the only ones.Prove it!

[Comrade_XRD]

There are untold numbers of galaxies that exist other than our own. I'm not saying that there are little green men someplace, but when you think of it we are really insignificant. Think about other versions of Earth in other galaxies, people like us. As for our own galaxy, or universe, I'm not quite sure if any intelligent life exists, outside our planet. All I know that NASA spends billions of dollars searching for it, and I'm sure that they wouldn't be playing hide-n-go-seek with us. So maybe there isn't any life on Mars?

[ÑóẊîöʼn]

Prove it!

The question of extraterrestrial life is an open question that has not been decided either way. But speculation (which is all that we can do at this point, and is perfectly valid) can be informed by discoveries in relevant fields, adjusting the parameters of the Drake equation.

We are beginning to get a clearer picture of the chances of life. Even our currently primitive instruments have been able to detect over 300 extrasolar planets. Proposed observatories such as Darwin (http://en.wikipedia.org/wiki/Darwin_%28ESA%29) and the Terrestrial Planet Finder (TPF) (http://en.wikipedia.org/wiki/Terrestrial_Planet_Finder) would help to refine our planet-hunting ability. Both TPF and Darwin would be able to take spectrometer measurements of any planets found, further refining results.

With the above in mind, I think it probable that life exists elsewhere in the universe, and highly improbable that life on Earth is just some wierd fluke. However, as I noted in an earlier posts, the extraterrestrial life in question would be under different constraints and conditions than life on Earth, meaning that evolution would in all likelyhood take a different path. We might not even recognise it as life at first.

We may not be able to "prove it" but we can make a stab at establishing probability, something that, I believe, we are working on.


Define "luck." I'd say our ancestors were "lucky" not to die along with the dinosaurs.Yet here we are. Apparently chaos theory works both ways?

[Forward Union]

The original question asked if we think intelligent life exists outside Earth. I argued that since we don't actually have any grasp on the probabilities of intelligent life developing, and since we never will know the probabilities of that life being destroyed, then we ought to proceed as though the answer to the question is "no."

No, that's not the most rational answer. Because it's definative and based on faith that no evidence of life will come to be (which it might)

The only correct thing to say is that "we don't know" that "there is no evidence of life in space at this time" but there is "every possibility", though the probability is near to impossible to calculate.

[mikelepore]

Umm, I used to think that it was absurd to think that the universe wasn't infinite, after all, what can exist outside everything?

Then I read about how most scientists in the relevant fields don't actually think the universe is infinite.

Then I realised I didn't have enough evidence or knowledge to make a judgement either way, and I just stopped thinking about it.

I don't understand the math in this area very well, but if curved four-dimensional spacetime has a spherical Reimann geometry instead of a hyperbolic Reimann geometry, which depends on the value of a parameter called omega, then the universe has a finite radius even though it has no boundary. This is hard to visualize. If you were to travel in a perfectly straight line far enough, you would find yourself back at the starting point.

[DesertShark]

Define "luck."
I used the word luck in response to this post:

We are products of a long sequence of one-in-a-million chances. The rarity of liquid water is often discussed, but there's a lot more. One big factor, there were many mass extinction events, but instead of wiping our our niche, they all happened at the right moments to wipe out other animals to make the room for our niche. That's incredible luck.
So you should ask this poster, what they mean by "luck."


I'd say our ancestors were "lucky" not to die along with the dinosaurs.
That actually has nothing to with luck. Any large environmental changes and mass extinctions kill off the biggest/largest critters - partly because they need more food to survive then little critters, they can't dig burrows in the ground for protection from the elements, etc. Also, some dinosaurs survived (the small ones, like the small mammals) - see birds.


Prove it!
You want me to prove how old and big the universe is?

The universe is too large and too old for us to be the only ones. If all the galaxies in the universe were shrunken down to pea-size, they would overflow a basketball arena. Our galaxy (Milky Way) alone is 100,000 light years across (ie traveling the speed of light it would take 100,000 years to cross). And we're just one solar system in this galaxy.
^that was from the History Channel's new series on the Universe
http://en.wikipedia.org/wiki/Universe
http://www.history.com/content/universe/facts-about-the-universe
^I believe they got their information from NASA and satellites photos
http://map.gsfc.nasa.gov/universe/uni_age.html
http://map.gsfc.nasa.gov/universe/uni_expansion.html
http://map.gsfc.nasa.gov/universe/uni_life.html
the last 3 are from the same website

[Comradeship]

I think that there are all kinds of mysteries and life in the universe... Maybe even life made up of something very different from DNA/RNA... Intelligent life might be rare, but it must exist! It would not make sense to me if there was no other intelligent life out there.
But of course, chances are we are too far apart to ever see each other.

Talking about extraterrestrials, I believe that life on Earth did not come from Earth... Instead it was carried to Earth through space by meteor, spores or something else. It is the only sensible reason for the existence of life on Earth to me... Unless spontaneous generation is true; which would allow for cells to come out of nowhere like quantum particles do.

[Picky Bugger]

Talking about extraterrestrials, I believe that life on Earth did not come from Earth... Instead it was carried to Earth through space by meteor, spores or something else. It is the only sensible reason for the existence of life on Earth to me... Unless spontaneous generation is true; which would allow for cells to come out of nowhere like quantum particles do.

Hmmm I think you are wrong here both in your choice of words and your reasoning. Richard Dawkins discusses in The Selfish Gene the idea that simple molecules existed in the primordial soup and that these molecules became replicators which replicated then mutated/ changed into more complex molecules then organisms etc. This is an incredibly brief recap and since its from memory it probably isn't wholly accurate but the point stands. It seems that jumping to the conclusion that life was created on another rock somewhere is illogical as what is to say that anywhere else held the properties to develop simple organisms more so than earth. To me it is more obvious to look at home before going away.

[ÑóẊîöʼn]

Besides, it just moves the problem somewhere else. Life would have had to arise somewhere, even if it isn't here.

[Voice_of_Reason]

The universe is to damn big, thinking that we are the only ones out there is a little self-centered.

[synthesis]

The question of extraterrestrial life is an open question that has not been decided either way. But speculation (which is all that we can do at this point, and is perfectly valid) can be informed by discoveries in relevant fields, adjusting the parameters of the Drake equation.But most of you don't see it as speculation. You see it as a certainty, something in which you seem to have an unshakable faith. It has to be so. We're just not that important. We're too insignificant. This can't be all there is.

What if that weren't the case?


No, that's not the most rational answer. Because it's definative and based on faith that no evidence of life will come to be (which it might)

The only correct thing to say is that "we don't know" that "there is no evidence of life in space at this time" but there is "every possibility", though the probability is near to impossible to calculate.I'd say it's less definitive and requires much less faith than the most popular answer to this poll. :)

(For the record, I picked the third option.)

[RedAnarchist]

The universe is far too big for us to ever say that Earth is the only planet where sentient beings exist. We may, sometime in the distant future, come into contact with one or two alien lifeforms who have intelligence, but this could be millenia away. I believe that there are intelligent lifeforms on other planets, just not the little green men of popular culture.

[synthesis]

You want me to prove how old and big the universe is?

No, I want you to prove that the size and age of the universe guarantees the existence of other intelligent life.

I mean, for all we know, there is a one in a billion chance that a star will develop life, and a smaller chance that life will become intelligent, and an even smaller chance that same life actually exists as we're sitting here in front of our computers. To me, it's a statistical miracle that we're here now.

[ÑóẊîöʼn]

But most of you don't see it as speculation. You see it as a certainty, something in which you seem to have an unshakable faith. It has to be so. We're just not that important. We're too insignificant. This can't be all there is.

What if that weren't the case?

The only way to to even begin to truly settle the matter is go out there and look. Until then we can only talk about probabilities. Of course, there are good reasons to colonise the universe that don't involve extraterrestrial life, but it's a bonus nonetheless.


No, I want you to prove that the size and age of the universe guarantees the existence of other intelligent life.

It doesn't guarantee it, but it makes it more probable.

[DesertShark]

No, I want you to prove that the size and age of the universe guarantees the existence of other intelligent life.

I mean, for all we know, there is a one in a billion chance that a star will develop life, and a smaller chance that life will become intelligent, and an even smaller chance that same life actually exists as we're sitting here in front of our computers. To me, it's a statistical miracle that we're here now.
It doesn't guarantee it but it makes it highly probable. Think about this: in our galaxy alone there are 200 billion to 400 billion stars. There are anywhere from 125 billion to 500 billion galaxies in our universe. Let's just go with 200 billion stars and 125 billion galaxies for easy math...that would mean: 25,000,000,000,000,000,000,000 stars. Let's say there's a one in 100 billion (100,000,000,000) chance of intelligent life; that would mean 250,000,000,000 forms of intelligent life....that's a hell of a lot.
The actual number of stars in the universe as of 2003 was 70,000,000,000,000,000,000,000 (45,000,000,000,000,000,000,000 more then my estimate) and that's only the visible ones, there's probably more.
So its not a miracle we're here.

[Sarah Palin]

Has anyone ever read up on type I, II, and III, civilizations? They are the possible types of civilizations out there, and apparently, we are type .75

[ÑóẊîöʼn]

Has anyone ever read up on type I, II, and III, civilizations? They are the possible types of civilizations out there, and apparently, we are type .75

You're talking about the Kardashev Scale (http://en.wikipedia.org/wiki/Kardashev_Scale). It seems we're closer to 0.71, going by 2004 figures.

I think the Kardashev Scale gives a good idea of "what to keep an eye out for", but actively searching for Type II and III civilisations may be "jumping the gun" so to speak, since we have yet to determine just how common in the universe life is in the first place.

[pastradamus]

In answer to the question, yes. I do believe there is life outside earth. Whether or not you believe it could be described as "intelligent" or not is up for debate obviously. However the likes of UFO's and Alien abductions is completely absurd and idiotic.

[synthesis]

It doesn't guarantee it but it makes it highly probable. Think about this: in our galaxy alone there are 200 billion to 400 billion stars. There are anywhere from 125 billion to 500 billion galaxies in our universe. Let's just go with 200 billion stars and 125 billion galaxies for easy math...that would mean: 25,000,000,000,000,000,000,000 stars. Let's say there's a one in 100 billion (100,000,000,000) chance of intelligent life; that would mean 250,000,000,000 forms of intelligent life....that's a hell of a lot.
The actual number of stars in the universe as of 2003 was 70,000,000,000,000,000,000,000 (45,000,000,000,000,000,000,000 more then my estimate) and that's only the visible ones, there's probably more.
So its not a miracle we're here.

My problem is that most people don't even consider our lack of knowledge about the possibilities. It is hard for my inner skeptic to avoid wading into a topic that, for its adherents, seems to share many aspects of religion; among them is an unshakable faith in the existence of extraterrestrial life which, in turn, gives us a sense of existential comfort... kind of like the all-loving New Testament God. We just can't be all alone.

We have far too much to learn about our own origins, both as a collection of particles and as a species, to make any assumptions here. That's what I'm getting at.

[Stranger Than Paradise]

Yes I definitely believe there is life outside of earth. There would have to be, the minute amount of space we can travel to how could we ever know that there isn't other life forms elsewhere?

[9]

Its quite possible that there is life within our own galaxy, granted it is certainly not intelligent, and in fact, would be of the most rudimentary form. Take the methane seas on Titan, one of Saturn's moons, for example.
Whether there is "intelligent" life.. there certainly isn't within our own galaxy, but whether or not there is in the distant reaches of the universe is really a toss up... something we can only speculate about, and I don't believe humankind will ever know.

[Q]

Whether there is "intelligent" life.. there certainly isn't within our own galaxy, but whether or not there is in the distant reaches of the universe is really a toss up... something we can only speculate about, and I don't believe humankind will ever know.

What makes you so certain of both assertions (no intelligent life in our galaxy and we will never know)?

[Decolonize The Left]

My problem is that most people don't even consider our lack of knowledge about the possibilities. It is hard for my inner skeptic to avoid wading into a topic that, for its adherents, seems to share many aspects of religion; among them is an unshakable faith in the existence of extraterrestrial life which, in turn, gives us a sense of existential comfort... kind of like the all-loving New Testament God. We just can't be all alone.

We have far too much to learn about our own origins, both as a collection of particles and as a species, to make any assumptions here. That's what I'm getting at.

We're not making assumptions, we're making educated inferences given our present-day knowledge. There's a huge difference.

What DesertShark just outlined was a rudimentary example of why it is highly probable that extraterrestrial life exists - this is a not an assumption, it is justified belief.

- August

[Cumannach]

If there's intelligent life elsewhere in the Universe, why are they hiding?

[-marx-]

I believe that alien life forms exist and have visited earth many times. I've seen unexplainable aircraft do maneuvers not possible by our own aircraft and I've also seen some good video evidence of this also.
Its only a matter of time before mankind accepts the fact that we are not alone and that we have been being visited for hundred if not thousands of years.
I also don't think they are hostile because if they were we would have known about it long ago, why they come here...I don't know.
Of course, I cant prove any of this so I don't try to.

[Q]

If there's intelligent life elsewhere in the Universe, why are they hiding?

Who says they do?

We just started transmitting radiowaves since the end of the 19th century, so these waves - travelling at the speed of light - have now reached a "bubble" around the Earth of about 100 lightyears. Say another civilisation has started sending out radiowaves, the most obvious way for us of determining extraterrestial intelligence, 5000 years ago but is at an distance of 25 000 lightyears from us. It'll still take a while for these waves to start reaching us.

There is no hiding, the universe is just vastly huge.

[NecroCommie]

I strongly propose trashing this thread and never speaking about extraterrestrial life again in this forum. I'm a CIA agent and it would be regrettable if this forum... say... ceased to exist? The scientific illiteracy of this thread baffles me, and it would be a shame if any of you would flaunt about their ignorance by claiming that this conversation ever took place.

[Picky Bugger]

I believe that alien life forms exist and have visited earth many times. I've seen unexplainable aircraft do maneuvers not possible by our own aircraft and I've also seen some good video evidence of this also.

Bloody hell I hope you're joking...

How do you known the current level of top secret aircraft? and anyway something such as the Harrier can do maneuvers that that many people would not expect from a aircraft.

As for videos you do know they can very easily be misinterpreted and even worse easily hoaxed. For instance some woman in Mexico claimed she saw UFOs every night above a near by volcano, she took this as a sign from the aliens warning us about an imminent eruption. Yet the bright lights and moving objects were just made of gas release from the volcano created by small earthquakes. These gas leaks were being illuminated by the setting sun. It is very easy to misinterpret fairly mundane things if you're looking for something in particular.


I also don't think they are hostile because if they were we would have known about it long ago, why they come here...I don't know.
Of course.For all you know they could very easily be spying on us until they have enough 10 armed super alien soldiers or until their new quad-laser grenade launchers have been put into mass production. :rolleyes: This is of course all entirely propostorous just like the notion we have been visited by aliens for millennia. There is no reliable evidence for them visiting...

[Stranger Than Paradise]

Bloody hell I hope you're joking...

How do you known the current level of top secret aircraft? and anyway something such as the Harrier can do maneuvers that that many people would not expect from a aircraft.

As for videos you do know they can very easily be misinterpreted and even worse easily hoaxed. For instance some woman in Mexico claimed she saw UFOs every night above a near by volcano, she took this as a sign from the aliens warning us about an imminent eruption. Yet the bright lights and moving objects were just made of gas release from the volcano created by small earthquakes. These gas leaks were being illuminated by the setting sun. It is very easy to misinterpret fairly mundane things if you're looking for something in particular.



There is no convincing evidence EITHER way. I think it is silly to both confirm or deny that aliens have visted earth.

[Dooga Aetrus Blackrazor]

Material evidence is not convincing.
The argument that the "world is too big" is strangely similar to "the world is to complex" argument for God's existence. The Drake Equation uses number estimates that could theoretically be zero and refute the conclusion.

Even if the size of the universe is enough to justify belief in other planets, we have no access to the probabilities of life originating on one. People generally assume that the probability of life is "1 in a billion" or something generously large to satisfy the skeptics. Well, you have no idea what the probability is. It could be infinitely high to the extent that the universe only catches up in extremely rare circumstances. It could be reasonably low.

The point is we don't jump to belief with unclear and unjustified data. People generally want to defend their ideas no matter what, though, so nobody will probably change their mind. I changed my mind when it comes to outright mocking the possibility (thought I could change it again). It has been my experience with professional astronomers that belief in aliens is rather uncommon. My experience is limited, but when I combine it with my own views, I can only conclude a position of skepticism.

Curiosity is enough to justify the search, but I don't think we need aliens to be curious about what's out there. It just helps NASA get funded if let that belief stick around.

[Picky Bugger]

There is no convincing evidence EITHER way. I think it is silly to both confirm or deny that aliens have visted earth.

No but the lack of evidence points towards the answer that aliens haven't visited earth.

[Stranger Than Paradise]

No but the lack of evidence points towards the answer that aliens haven't visited earth.

Yes I agree. But there is also a lot of unexplained things which COULD be something. I'm not saying I think they are, but at the same time I wouldn't completely dismiss them.

[Picky Bugger]

Of course but it is more likely that it will be something that is derived this planet like with my previous example. I have seen nothing that does not corroborate my feelings that the UFO phenomena is fueled solely by hoaxes and Hollywood.

[Stranger Than Paradise]

Of course but it is more likely that it will be something that is derived this planet like with my previous example. I have seen nothing that does not corroborate my feelings that the UFO phenomena is fueled solely by hoaxes and Hollywood.

Yeah I suppose. I'm more susceptible to believing the hoax rubbish though. I love a conspiracy.

[Q]

Aliens have in fact visted before. And the proof is in plain sight:

http://upload.wikimedia.org/wikipedia/commons/archive/7/71/20051023134432!Engels.jpg

And everyone thought it was a beard...

[brigadista]

its hard:) enough finding it on earth..

[Stranger Than Paradise]

Aliens have in fact visted before. And the proof is in plain sight:

http://upload.wikimedia.org/wikipedia/commons/archive/7/71/20051023134432!Engels.jpg

And everyone thought it was a beard...

He's a ballchinian