So basically, an unsolved problem? America can fix it.

stop that

Hmmm. Maybe we have not encountered intelligent life because we have not really travelled beyond our solar system yet?

I'm confident one day we will meet brothers and sisters in the stars, on such large scales, we have no cause to be impatient after a mere 10,000 years of development. Give it time. Accept we were probably born too early.

The idea is is that even if an infinitesimal number of planets give rise to intelligent space faring civilizations, and those intelligent space faring civilizations have had potentially billions of years of a head start (our solar system is relatively young) one would likely have become a giant interstellar civilization by now encompassing the entire galaxy if there is no limit on their expansion (or if the desire to expand is there). The idea is that if a civilization got that huge we would see or hear some sign of it. The question is why we don't see ANY sign of any intelligent civilization. Its not a matter of travel on our end (it might be on their end if our corner of the galaxy is particularly "rural" or undesirable.

"we have no cause to be impatient after a mere 10,000 years of development." Its not the 10,000 years on our end, its the millions or billions of years on their end.

In other words, I'm not sure if I agree that locating alien life is something to be achieved by civilization, like a technological advance. If anything, they'll call us.

And I'm saying maybe there was nothing interesting to that space race about our area until we appeared, and maybe travel at those distances really does take thousands of years. Do you pretend to know what alien species are or aren't potentially capable of?

@ SantaClausowitz: " Its not the 10,000 years on our end, its the millions or billions of years on their end."

I'd suggest that if an intelligent spacefaring race had visited Earth billions of years ago, looking for intelligent life, it's unlikely they would have found much.

I don't, but my point also is that it doesn't matter what they are capable of, its what we are capable of observing. Perhaps we don't have the ability to observe it, but if there were interstellar civilizations all around us I would think that there would be observable signs. And traveling isn't a factor at all, if anything we would her these civilizations before we see them, unless of course they wouldn't want that.

it'd be more likely that if there was by now a massive galaxy or multi-galaxy spanning empire they'd be communicating and working in methods that we are not specifically looking or listening for. It might not be the smartest for such an empire to expressly advertise themselves to the whole universe as well.

Space is big, really big, and we are really small. We can look and see but we still have very little information on whats out there. Just a reminder that the very idea and evidence of an abundance of Earth-like planets is only recently a new thing outside of science fiction.

a possibility

Or they've already taken a look at us and are avoiding us.

The point is that we will never know we are alone unless we find out we aren't, because in Nature anything is possible.

We will also never know that we are not alone unless we somehow find out we aren't. This is just Schrodinger's Cat.

Surely mathematical probability makes it a certainty that we are not alone?

Nope...it just makes a great argument for it being probable. :-) Which just leads to, "OK, then why can't we see them?" and threads like this. Interesting question.

Define "alone" in this sense. We are the only species we have ever met capable of flight and underwater travel that wasn't born with the natural equipment to do so. And we are the *only* species we have ever met to put itself in space. Considering we have never met a second species, we have no way of even guesstimating what the odds are of intelligent life appearing on another planet capable of life. For all we know, the odds are 999 googleplex to 1.

Who believes we are alone in the universe? If it's you your a moron. Will we ever encounter other life forms, not if you believe in the laws of physics as we know them. If we can't travel at speeds greater than light, we will never run into anything EVER.

You started off on a good path there ssorenn and then ... what?

What don't you understand. The closest star,(not even habitable) alpha centari is what100 light years from earth. The Hubble telescope thinks it's found possible planets that might support life as we know it,150+ light years away???so without the possibility of traveling fast than the speed of light( which is not possible under the laws of physics ) were never going to run into extraterrestrial anything.

We don't have to physically reach them to know they're there. We won't see anything in our lifetime, but I wouldn't say that we'll never branch out to other solar systems.

you don't need to travel at the speed of light or greater, you just need to accelerate to near speeds of light and be able to deaccelerate. That would enable long distance travel in very short times.

Again oh simple minded Bo, I think there are sentient beings somewhere out there...but until our laws of physics are disproved and we figure out something different. We will never run into extraterrestrial life forms.

the laws of physics still allow for travel across space ssorenn, and there are even potentially loopholes we can exploit (http://en.wikipedia.org/wiki/Alcubierre_drive)

@chairman moron, without breaking the threshold of light, your at 100+ years of travel to reach just the nearest star.. Space by its volume is something that none of us can actually comprehend. So set off to alpha centari and figure out a way to survive for 100+ years and let us know what you find

Until our laws of physics are disproved? They're not about to be "disproved." They may change in other places outside of the small section of the universe our technology has encountered, but that's it.

It's highly likely that we're not alone. It's unreasonable to think so, given that there's two planets (potentially three - was Venus once habitable?) and plenty of moons in our solar system alone that could have/could still potentially support some form of life. We also don't have to physically move our bodies to another part of space to have a meet and greet with said extraterrestrial life forms. We could pretty easily send communication back and forth, of course taking years to go from place to place but still possible. Carl Sagan already got the ball rolling on that one.

You're really quick to call everyone else morons when you're making a probably bold and completely incorrect statement. You're only considering one type of travel when there are many options available. Even if we have to deal with slow interstellar speeds, the potential for things like long term cryogenic sleep would make travel across space totally possible.

That is again, even not considering the potential to bring yourself to 99% the speed of light which would be adequate enough for travel. Consider that Alpha Centauri is only 4 light years away, not 100.

I said, I believe life is out there, we are just never going to find it at our current available scientific capabilities