ishalon

Seeing that its relatively simple for live to evolve, and abiogenesis has occured here, everyone (atheist) here should agree that aliens exist?

Then again, if you're theist, why would God have created the universe just to put us in it?

Jayman

Suppose some day humans can travel to hundreds (if not thousands) of earth-like planets. If no life was found on them, would that cast serious doubt on the possibility of abiogenesis for you? Please explain your answer.

Liquidrage

I belive in the high possibility of alien life due to the vast amount of places that appear to exist where it could form.

Considering it looks like there's at least 1,000,000,000,000,000,000,000 stars in the known universe, if I was a betting man I'd say somewhere out there is life and most likely a lot of it.

Liquidrage

abiogenesis isn't a question of "if" but a question of "how". We know we're here.

Vast amounts of barren planets looks just as silly to a god as it does to a science. Actutally, more so.

elwoodblues

Don't even bother constraining yourself to a rigid set of planets in a set of systems orbiting specific kinds of stars. Hell, even the Oort cloud and similar vast trenches of space have become increasingly attractive as breeding grounds for primitive life (the theory being that passing asteroids then 'seeded' the earth).

The only real objection is an old one. 'If all these aliens are supposed to be out there, then where are they? Why no sign of them?' I've never really heard a satisfactory answer to that. Then again, I don't think it's fair to pose the question without assuming certain things about the nature of these hypothetical aliens, which weakens the argument to begin with.

We need to assume things like aliens would be signaling in mediums we would be capable of receiving and understanding (a vaster assumption than you may think at first). Even more than the assumptions I can spot, it's the assumptions I CAN'T spot about these hypothetical aliens that'll throw things off, the things we so automatically assume that we don't ever even realize it.

[ June 16, 2002: Message edited by: elwoodblues ]</p>

schu

It could be that although life in the universe is very common, intelligent life may not be. We like to think of ourselves (humans) as the pinnacle of evolution. (Some new thinking is that the hyperactive among us lead the way.) The chance happening that was selected to make us what we are could be unique. The Neanderthal didn't seem to change in over 250 thousand years. Homo erectus was around what 2 million? The humanoids that where our ancestors could have been wiped out by an extraterrestrial impact at any time during their development. Then where would we be? I don't think there is any law that states intelligent life has to evolve. It took 3.5 billion years for intelligent life to evolve here. That is about one forth of the time the universe has been existent and then it only happened once as far as we know for sure. I don't know that the odds are all that good for intelligent life to have evolved anywhere in the universe close enough to us that we could expect to make contact with them.

Bookman

Don't forget that the universe appears to have a rigid speed limit which makes popping by for a visit a little less likely.

Bookman

fando

Ah yes, the famous Fermi Paradox. The strongest resolution to this paradox is that the speed of light is insurmountable and that life as complex as us is rare. Exactly how rare is the big question these days, and that's why there's a ton of research in exobiology and exoplanet discovery. Provided that there are no special communication techniques that we're not aware of, it is highly probable that intelligent life is exceedingly rare. I would place my bets on not finding other thinking beings in this universe for a long time to come. However, I'm fairly certain that we'll find conclusive proof of simple life existing outside of Earth within our lifetimes.

Oolon Colluphid

Erm, maybe distance has something to do with it?

In the same way as we humans cannot cope intuitively with the vast spans of geological time, we cannot really get a handle on the vast spans of space. A mere hundred light years means exactly that: something travelling at the fastest speed possible will still take a hundred years to get there. A single light year is about 5,865,696,000,000 miles. And a hundred light years is like walking down the garden, compared to even the distance to the next galaxy, which is like walking to Melbourne from Glasgow.

And you’ve got to think in 3-D. Remember the volume of a sphere is 4/3 pi r^3... well that radius is light years. The ratio of distance to volume goes up by those proportions. Someone with a scientific calculator can tell us what the volume of a hundred-light-year sphere is in miles... but I think it’s quite a lot. That’s how much space there is within a mere 100 light years of us (or them). That much space has a lot of stars in it.

Why aren’t they here? Because it’s too fuckin far to come, and they wouldn’t be able to find us even if they tried.

Cheers, Oolon

fando

While distance has a lot to do with it, it's not really the strongest argument against the Fermi Paradox. The reason is that we should be able to detect the signals of any reasonably advanced civilization given the amount of time that has elapsed since the begining of star formation. There are, after all, 100 billion stars within our galaxy and it takes only one civilization to make enough noise to be detected by chance observations.

A more convincing argument is that the probability of an advanced civilization forming and lasting for a long time is very low. There are lots of factors involved in the computation (Drake equation), and some are only recently coming to light.