Extraterrestrial life (did I spell it right?)

[Wildor]

No mountain nor sea,
no thing of this world
could keep us apart.
Because this is not my world
...you are...

Montros, allow me to be completely off-topic for a second and say this is the loveliest sig!

[Rota]

But it's not like there are only two civilizations in the whole universe. There might be millions!!! Which means, for example, planet A might contact planet C, while planet B might contact Planet D, and so on. So, if there were a serious amount of civilizations in the universe, we're bound to find at least ONE civilization. If we're lucky, we may even find two!

But, as I said, if it's so easy to find a civilization in space, why haven't we found one yet? Project S.E.T.I (Search for Extra-Terrestrial Inteligence) is searching for some right now, but they've only found space dust and nebulas. Plus, they're also starting to lose some funds, and if they're broke, no more satalites for them. which means there will be an even lower chance to find intellegent lifeforms other than humans.

Granted. I probably chose my words poorly when i said "two."

But my point still stands.
Even if there are thousands of spacefaring species, the sheer mega-huge, utlra-big, enormously-large, (no bigger than that), and even bigger than that size of space means we are so incredibly unlikely to run into them.

Not impossible.
I'm just saying, that it's a heck of an ego to think Earth is even on their radar.

[Montros]

Well the thing is, if we were to actully find a civilization, its a high posibility that they are much more advanced than us. like you guys said, they might have space ships and lasers, but more important is the fact that they will probably have more experience in politics( since they've been in the universe longer), which means that they have also probably put violence and greed aside, kind of like a utopia.
Also, other civilizations can be more advanced than us not only because they may have evolved faster, but maybe because nature allowed a better "Learning environment". Earth, is just about right in the life zone. The life zone is the zone in space at which life can be sustained. But, Earth isn't exactly at the middle. If we were, it may effect how we live, such as better agriculture. Or, maybe we're just slow learners . For example, When there were futuristic technologies in India and Saudi Arabia, there was iron age technologies in europe, and stone age technologies in North America. This shows that some countries are slow learners, and some are fast.

[Montros]

Granted. I probably chose my words poorly when i said "two."

But my point still stands.
Even if there are thousands of spacefaring species, the sheer mega-huge, utlra-big, enormously-large, (no bigger than that), and even bigger than that size of space means we are so incredibly unlikely to run into them.

Not impossible.
I'm just saying, that it's a heck of an ego to think Earth is even on their radar.

Yes, you are also right. Maybe they're so intelligent that they think we're really puney and insignificant, so they don't even bother to look. They may even be in our backyard. Or maybe we're the most intellegent civilization and the others are really stupid and didn't even develop sliced bread yet.

Anyway, there is many possibilities, and your right. There is a small possibility we will find them. And like I said too, most of the other civilizations will most likely be more intellegent than us. And since they are, the thing with us being the smartest wouldn't be so realistic.

[Smythe]

are there extraterrestrials? -most deffinately 100% yes.

why? just go out at night and look up,,, even in a city with all it's pollution there are still more stars than i can count. Then there is the fact that a lot of those points of light aren't single stars, but entire galaxies with billions and billions of there own stars,

so even if only 0.1% of stars have planets - and only 0.1% of those planets have basic life - and only 0.1% of Those planets remain stable enough for long enough to develop complex life - and only 0.1% of THose planets lifeforms survive long enough to become 'advanced' that still leaves you with millions of extraterrestrial species out there.

The problem, i think, is the likelyhood of ever coming into contact with one of them. If human beings do come into contact with alien species, in the forseeable future, chances are that they would have come to us, as opposed to us going to them. so we can make a few assumtions;
1. they will be FAR more advanced than we are - because they are obviously capable of traveling such unthinkable distances
2. they probably didn't come all that way just to say hello
3. if history does repeat itself; we're screwed - [every single time in earths history when an 'advanced' people has come into contact with a 'less advanced' people it has been a massacre,,,

so lets hope they don't find us just yet i say

[theturkeywithin]

so even if only 0.1% of stars have planets - and only 0.1% of those planets have basic life - and only 0.1% of Those planets remain stable enough for long enough to develop complex life - and only 0.1% of THose planets lifeforms survive long enough to become 'advanced' that still leaves you with millions of extraterrestrial species out there.

That's good thinking except for the fact that the planets that have the conditions required to maintain the most basic form of life is FAR less then 0.1%. I'm not ruling out the possibility of other life forms existing, i'm just saying that it's unlikely. Just read my earlier post.

[that guy]

even if those lifeforms are only single cell organisms there are most definitely other planets in the universe which can host life other than our own. to believe otherwise is simply ludicrous

[TPUK]

It's a very complex question. You might view it with a sort of "the universe is so big life is bound to exist somewhere" kind of opinion or with a "the things needed for sustaining life are so specific we're lucky it exists at all" opinion. Personally, i go with the latter. Just thinking about the fact that you need water, oxygen (though not too much of it), etc. to all come together on a place that is not too hot and not too cold makes the odds incredibly small. Throw in the factors that you need two species (or one cannibalistic one) in the same place for food and reproduction and you reduce the odds even more. I also agree with the earlier posters in the fact that if life does in fact exist, we will never find them. Simply because we've searched so far and wide already that even if we did at last discover some alien race, there would be no way of sending word to them that we exist. Anyways, that's just my two cents.

This has come up in a couple of other posts as to the conditions for life to exist - this is based on out current understanding and knowledge. However although a carbon based lifeform is possibly the most likely since as early as 1891 it has been theorised that Silicone could also be a basis for life (and not just breast implants), Silicone based life forms could tolerate much higher tempreatures so this would increase the amount of planets that could potentialy sustain life. Whilst current scientific theories put forward say that Silicone life forms are unlikely for a variety of reasons this is again based on our current knowledge and understanding.
As to how wide we have searched so far not very much in the scheme of things it is very much like searching for a specific grain of sand on a beach, we might if we get lucky find it quickly but the chances are it will take a long time

[Alusair]

Ooo, a fun thread.

Here's a little interesting read for those interested:
http://en.wikipedia.org/wiki/Drake_equation

Unfortunately I can't find the theorized number of planets that could exist in the universe, but this is as close as I can find at the moment:

Based on observations from the Hubble Space Telescope, there are at least 125 billion galaxies in the universe. It is estimated that at least ten percent of all sun-like stars have a system of planets, [and] there are 6.25?10^18 stars with planets orbiting them in the universe. If even a billionth of these stars have planets supporting life, there are some 6.25 billion life-supporting solar systems in the universe.

With that said, the odds of there being another planet being able to support life is fairly decent, and there are some planets within (relatively speaking) range of Earth that are theorized to potentially be able to support life, such as Gliese 581 d.

Of course, this is assuming that a world has to be Earth-like to sustain life. So far we can only use life on Earth as a reference, so it's hard to say what other possibilities there could be.

However, while the odds of basic life (IE, micro-organisms) or perhaps even primitive animal life can be fairly decent, the odds of intelligent life is slimmer, I'd say. Considering of all the races that have existed on Earth, mankind is the only one to become a sentient species (as far as we know ;)), it's probably safe to say the ratio of "primitive life vs. sentient life" across the universe could be equally probable (or improbable, in this case).

That's not to say I believe we're the only race to be that way, though. I do believe there could quite possibly be other intelligent lifeforms in our universe. However, considering the diameter of the "observable universe" is proposed to be at least 93 billion light years, I'd say the odds of us bumping into them would be about the same as two randomly chosen specks of dust crossing paths somewhere on Earth. And even that comparison is probably rather generous.

I'd say we have better odds of inventing sentient AIs first. :p

[fleabird]

The problem, i think, is the likelyhood of ever coming into contact with one of them. If human beings do come into contact with alien species, in the forseeable future, chances are that they would have come to us, as opposed to us going to them. so we can make a few assumtions;
1. they will be FAR more advanced than we are - because they are obviously capable of traveling such unthinkable distances
2. they probably didn't come all that way just to say hello
3. if history does repeat itself; we're screwed - [every single time in earths history when an 'advanced' people has come into contact with a 'less advanced' people it has been a massacre,,,

so lets hope they don't find us just yet i say

I agree! If they are out there, why would we send out beacons with directions to our planet?? It's like a buffet advertisement: We have water and delicious meat and we are defenseless! Our only hope to win against you is a cool voice-over by Morgan Freeman or total pwnage by Jeff Goldblum uploading a virus into your mother-ship with his uber-cool laptop.