I once got into a very intense conversation about the planets in our solar system and the chances that we may be sharing it with other “more advanved” lifeforms that are completely unknown to us. Of all the planets, moons and asteriods within our solar system alone, (not to mention the countless stars, galaxies, and other constallations out there), Do you think that its highly possible that there are other beings far more advanced than we could ever be that share the stars with us. Beings that knows of our existance but have yet to reveal themselves? (To me its highly probable)
We’re not alone in the Universe. We;'re just alone on this floor. But pretty soon the Things Upstairs are going to have a party, and it’s going to get noisy, so we’ll have to bang on the ceiling with a cosmic brromstick.
If they’re out there they’re not in this solar system. Which puts them so far away that they’d almost certainly have plenty of other problems to sort out before getting anywhere near starting to look for us. And once they’re advanced enough to locate us and then travel those ludicrous, untravellable distances… why would they want to communicate with people so much more primitive than themselves?
My WAG, whatever that is, is that the universe is too darned big.
Thinking that we are alone in the universe is absolutely absurd. It’s highly more probable that we AREN’T alone than we are.
As far as them knowing of our existance? Eh, that’s anybodies guess.
From our POV it’s pretty much moot anyway, untill we do (if ever) come in contact with said beings.
I still refuse to believe that it would be impossible to come in contact with other beings becuase they are simply too far away. That’s actually a pretty arrogant staement to say, as there are a myriad a facts we still do not know about the physical nature of our universe.
But going by what we do know, it doesn’t look too likely to me. As for ‘arrogant’… well, I may be wrong, but please bear in mind, sir/madam, that you are not dealing with some hobbledehoy - you are addressing a man who has vaguely skimmed a couple of articles in Scientific American until I got bored with all the maths.
We’re here, so that’s at least one datum for the possibility of life elsewhere. Life is probably not common in the universe because a planet has to have a steady sun (not variable) at a safe distance (not too close, not too far) in a quiet section of the galaxy (no gamma ray bursts, no inconveniently close supernovae). Still, given the size of our galaxy, its certainly possible that there life-bearing planets here and there in our galaxy, which would be the only life we have a remote chance of detecting. Life in other galaxies will forever remain out of our reach.
No, actually we know quite a lot about the physical nature of our universe, specifically that the speed of light is limiting. Essentially, you have to have fuel to get a spaceship to move. If you want it to go faster, you have to add more fuel. Given that energy is equivalent to mass (E=MC[sup]2[/sup], remember?), the velocity of the spacecraft means that you have increased its mass, which means that you need even more fuel. The more fuel you add results in incrementally smaller increases in velocity until you are equiring vastly greater amounts of fuel than you can ever hope to provide, and you STILL haven’t gotten to light speed.
But even if you could get your craft to fly at C (which you can’t), the nearest star, Proxima Centauri (a red dwarf star which has no planets, so why even go?), is a 7-year round trip, and THAT’s just if you go and come back with no time spent there.
Alone, perhaps not. But isolated, most likely yes, barring some serious breakthrough that gets us around that speed limit (really a time limit, to think of it – if my life expectancy were 72 thousand years, I would not mind spending 600 travelling to some interesting star). To gobear’s set of circumstances, you also have to throw in the likelihood that the lifespan of the biospheres, never mind specific species, would overlap. We often forget that everything alive dies and entire biota can go extinct.
As to “more advanced life-forms”, I’ve often been amused by the idea that exospecies would be “more advanced”.
If we go into the realm of forms of life that are of a nature and essence such that we cannot detect or recognize it, and you throw in something like “they have yet to reveal themselves”, well, then we might as well discuss if there are gods out there. Would make no damn difference if they are or not. So let’s stick to life, whatever its form or substance, that we could see, touch or at least detect on some sort of instrument if we knew what to look for.
Then we’d still have to define “advanced”. If it’s about the life-form itself, that’s meaningless: it has evolved to be optimized for its environment. If it’s specifically about technology or social development among sentients, well, some would be “advanced”, some would be “backward”, relative to us, at any given time. You could have a very active, complex ecosystem with no technological species arising before the star burns out. Or a series of intelligent species that manage to repeatedly collapse their civilizations all the way back to barbarism every 3,000 years, just as they’re getting to where we are now.
I think they are out there. I would imagine we will discover intelligence will and can be in formed we never thought possible. Don’t ask me what, I don’t believe for an instance I have the imagination to imagine something beyond my Imagination. 
I imagine intelligent life is rare. Much more rare than life itself- which I don’t believe is all together rare in some contexts. Comparing the rarity of life to the number of Hydrogen atoms in the universe would prove life to be very rare indeed, but instead comparing it to the number of times it happens within a certain paramater. (like type of star)
Do I imagine that Alien life is visiting us now as I type this? I would certainly like to- the idea of new technology, space travel, a good slap in the face of our ego, etc. However, I find it a bit ludicrous to imagine any space-faring species taking the time to come all the way here, just to anally probe us and create controversy- not to mention telepathically speak to a select few “nobodies”, and not communicating with our goverments. I find it equally ludricous of an idea that they goverment could keep it a secret. It sure is possible, but so far down on the probability chart as to be, I hate to say it, impossible.
Alone in the Universe? Unlikely.
Alone in our galaxy? Possible, though a bit unlikely.
I can’t type today.
Formed should be forms.
Another vote for no, we’re not alone, but we might as well be.
Due to a staggeringly long list of natural circumstances all fitting together, there is intelligent life on earth that has come down from the trees, learned to control and use fire, invented the wheel, worked out steam power and electricity, learned to fly in machines heavier than air, launched the voyager probe, and built signalling devices that can call out series of prime numbers to the stars.
The amount of time we’ve got might be much longer than we’ve been around so far, but I’m reasonably well assured that the total amount of time the earth supports technology will be a miniscule fraction of the lifespan of the solar system.
Given time enough, the same thing most probably will happen again within several hundred light years of here.
And given distance enough, the same thing most probably is happening right now.
But the odds against two technologically advanced civilizations existing at the same time, within hailing distance of each other must be… well, astronomical.
My guess is that, in the entire universe visible to the Hubble Space telescope, there are maybe two pairs of civilizations that have managed to say hello to each other. In the entire lifespan of the inhabitable universe… maybe about a dozen pairs.
My assumptions are:
- Life is not the norm, but living things can probably be found in orbit around most stars.
- Conditions have to be pretty good for life to go multicellular. The amount of it time it takes, in billions of years, will vary widely and will often not happen within the lifespan of its host planet.
- Intelligent life is a rare exception, and is not an inevitable product of evolution… most creatures on our planet manage beautifully without even mollusc-level intelligence, so the evolutionary pressures that select for human-level intelligence must be very unusual and very specific.
- Intelligence does not automatically lead to advanced technology. In fact, from what I understand about it, an intelligent species is not very likely to learn to use electricity. There could be intelligent life closer to home, but there’s no reason to expect that they will inevitably live among the stars.
One caveat has to be placed on the term “life” when discussing whether or not a particular set of conditions is hospitable: “…as we know it”.
Could Pluto sustain life as we know it? No way. Can it sustain life? Certainly, why not?
One thing that often gets lost in discussions of alien life is that it is likely just that: alien. Not carbon-based. Without a central nervous system. Something completely foreign to us.
Just my $0.02.
No, you humans are not alone.
Too cold for the chemical processes of life. Any life.
One thing that often gets lost in discussions of alien life is that it is likely just that: alien. Not carbon-based. Without a central nervous system. Something completely foreign to us.
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We already have life without central nervous systems–bacteria or algae, for instance.
And silicon life is a non-starter. Read this article for the reasons why.
This is the closest thing to evidence of extraterrestrial intelligent life that I have seen, if you assume that some of the mystery objects could be artificial (like a spaceborne nuclear reactor.)
As I said in a recent GD thread on the subject, the only responsible answer is “we don’t know.”
We just plain don’t have enough information. We understand organic chemistry, and we know more or less how common various elements and compounds are in the universe, and we know about the life cycle of stars, and we can find extrasolar planets, and so on, and so forth: we have a tremendous body of knowledge from which to speculate. But it’s all speculation, in the end.
We have highly advanced probes on Mars, answering the important questions about geology (areology, actually) and chemistry and so on. We have confirmed our ideas about the presence of water, at least an extremely briny version of it. But we still have no idea what might be there more than three inches below the surface. Bacteria? Certainly possible. A massive underground civilization we cannot detect by ordinary means? Impossible to rule out, though highly unlikely. Can we say anything for sure? Not at all.
So, again, we simply cannot answer this question either way with any certainty. The range of answers goes from “we’re completely alone in the universe” to “we are hardly unique in a universe teeming with life.” Neither extreme is necessarily likely, but we cannot rule either out.
I was actually thinking about this last night, and it suddenly occurred to me that this may be the one question on which I, a hard atheist, can find common psychological ground with someone of deep religious faith. I am intellectually responsible enough that I must concede the possibility that life in the universe is unique to Earth, but for some reason this is distasteful to me, and I also admit that in my heart of hearts, I believe there must be life elsewhere in the cosmos. I have faith that this is true. In the absence of evidence either way, I am extremely uncomfortable with the prospect that we are alone, truly alone. I do believe there is life out there: not because there’s any good reason to think so (though I can certainly come up with a rationalization of it), but rather because, at some deep subconscious level, I must believe it, as the alternative is simply unpalatable.
I’m not really sure how I feel about this.
The only answer possible would have to be “I don’t know”. We don’t even have enough data to make a wild-assed guess, in my opinion.
With apologies to Tonto:
“What do you mean ‘We’, Earthling?”
If we are, it’s an awful waste of space.
No, it’s too cold for life as we know it.
Arguing against silicon-based life is fine, but that doesn’t speak to my point. We’re still updating our periodic table of the elements on our own planet. How can we use say that there isn’t an entirely different table on other worlds?
My main point here is that it’s perfectly logical that alien life would be completely alien to us. That it’s most basic genetic structure would be played out under an entirely different set of rules.
We’re extending the periodic table. We’re not finding any new elements between the ones we already have listed, because there aren’t any. Sure, there are many different ways to construct a table of them, but I can say with certainty that any putative alien life forms are going to have the same set of elements (albeit, in differing proportions) to work with as we do.