Hello again,
I was wounding what are the chances alien life could evolve. I've heard two sides, one very great due to the amout of stars in the univeres, and another that says very low due to the nessesary "ingrediants" for life. Whats your guys/gals take on this? Sorry if this has been done before.

__________________
Fate, chance, destiny, fortune.....There all ways of claiming your success without claiming your failures.

I definitely believe that there is Alien life somewhere in the universe. !00% in my opinion.

Intelegent life is a different matter. An civilization on par or more advanced than is in my book is 20%. Less than us goes up to 30%. (by advanced i mean thecnological skill).

Yeah the tempering thing with such discussion, is the sheer bulk of opotunities out there.

Our galaxy has (depending who you listen too) has between 60 and a hundred billion stars. Lots of chances for conditions to be right - and we do know they have been right at least once.

The harderst part is finding these other races amongst the clutter. The last statistic I saw on the subject suggest over fifty thousand star systems would need to be examined per alien race discovered.

Yes I know the figures were largely guesswork - but it gives you an idea how hard it will really be.

Glen Chapman

Yep, even though the chance that an individual planet will form life is very low, the sheer number (possible number) of planets out there make it approach certainty that there is alien life in the univers.

__________________
Hwæt! We Gardena in geardagum,
þeodcyninga, þrym gefrunon,
hu ða æþelingas ellen fremedon.

Life. Almost certainly.

Intelligent life. Extremely rare, but probably out there somewhere.

__________________
Everything I need to know I learned through Googling.

To someone else on another planet in another galaxy: we are alien life.

Well, there's alien life, and there's intelligent alien life as two possibilities. Life is likely quite common. I think we'll all be surprised if some form of extraterrestrial life isn't found within our own solar system.

Is this thread simply about alien life (not necessarily as we know it) or about intelligent alien life? I think the answer to that question will very much affect how we view the probability of extraterrestrial life forms.

My opinion (not based on much science) is that intelligent life will be very rare because it is only likely to exist for a very brief period of time on a habitable planet. Earth, for example has a 3.5 billion year history of life and for about 85% of that time, life was unicellular. Intelligence (as we'd measure it) has been here for maybe 100,000 years, civilizartion for possibly 10 - 20,000 years.

So if there are 100 billion stars in our galaxy, and we've found about 50 with planets and among that 50 only 1 that has a possibility of having an Earth-like planet, the odds become pretty slim that at this particular time there will be another planet in our galaxy that has intelligent life.

We can currently detect only gas giants and larger planets in other star systems, so we can't really say anything about the probability of finding terrestrial planets, life-supporting or not. At a guess, they are probably fairly common.

Our theories on the frequency of life are limited by necessity; all we can currently say is that life has come up once. From what I've read about planetary formation, it seems to me that we owe our existence to a number of chances:

1) The magnetosphere of Earth is the strongest of all the terrestrial planets, giving us protection against the solar wind.
2) The moon plays some part, though I'm not sure what. Perhaps the formation of the moon was what made the Earth dense enough to form a decent magnetic field. Tidal forces undoubtedly affect the geological processes too. Besides, the moon acts as a shield against incoming meteors.
3) The inclination of the rotation axis and the relatively quick rotation produce a more varied and even climate than might have been the case.

But without more data, this is just speculation.

__________________
"We do not require reality to conform to the expectations of the ignorant"

I'd urge you to read a fantastic high quality science book called "Evolving the Alien" written by Ian Stewart and Jack Cohen, check it out on Amazon. One of the best reads I have had in ages.

The opportunities for life are much more diverse than Astrobiologists like to believe/examine.

A very good read..

__________________
There we were in the park when suddenly some old lady says I stole her purse..... I chucked the professor at her but she kept coming..... So I had to hit her with this purse I found.
-- Bender

You can punch your own estimates into the Drake equation and try it out:

http://www.activemind.com/Mysterious..._equation.html

Not my site, just passing along the info.

Here are the aliens we have invented so far in our hard science fiction scenario; a mixed bunch indeed.
Intelligent life is very likely to be rare, non-humanoid, and very strange.
We only have a sample of one planet to go on; but we can make some predictions about life elsewhere by looking at the geological past...predicting the future is more difficult, so we don't know how long an intelligent race can exist before dying out.

__________________
Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

There are other threads that discussed alien life & the Drake equation, here's one of them.

I did a Drake equation where the Number of communicating species was 2. Us and them. In the entire galaxy, two.

__________________
Oswald: I know! The 'F' stands for 'Fun'!
Luis: HOW COULD IT POSSIBLY BE A BOX OF FUN?!

You take the Drake equation. Mulltiply by the squre root of negitive two. ! , Apply. Is the answer damn near one? Heck! Damm, I know Fermi's BS factor! All known sentients, times all the sentients, equals 1.

Of course, We have to settle on a definition for "intelligent." They may, for instance, not have the ability to communicate in a very complex manner (just very simple chemical signals, or something) and be able to build a spacecraft that can make it here from the Trelotan home world of Trelos IV. Or, they might be extremely good at complex communication and be very good in major areas of science, like comsology, astronomy, astro-physics, math, logic, etc... , but have no desire to advance technologically.

Or they may be as dumb as a rock, just strong enough and numerous enough to overthrow a dominent, smarter species which created warp technology, and just smart enough to operate it, somewhat.

Or they may be a little smarter than us, but not smart enough to be considered intelligent. #-o :wink:

Well, I've never really considered it something we could estimate. Maybe there is life on other planets...maybe it was a freak accident that only happened once...maybe life needs water and energy to exist universally, but then again maybe it doesn't. The fact is that we really have no idea at the moment. Of course, scientifically we have to work with what we know, but I still wouldn't put money on any of our estimates being correct.


That being said, I believe that if simple life is found anywhere in the universe, then intelligent life is very probable. I mean this planet has only hosted life for a couple of billion years and we already have one technologically advanced species, and a number of fairly intelligent species.

__________________
"Most editorials are written by people that love to argue but got kicked off debate team for not making any sense." -Seanbaby

I honestly don't think that question can be answered with any certainty.

We don't really understand the chemistry and thermodynamics of how life came to be. There are theories but nothing is proven. Because of this we cannot state with any certainty all the elements and conditions needed to create life - and therefore cannot possibly predict with any accuracy the probability of life existing, in whatever form, anywhere else in the universe.

We can, of course, speculate on the possibilities based on assumptions - like the assumptions that wherever the basic conditions (chemical and energy conditions) that existed when life presumably arose on earth exist, life may appear. This assumes first that life arose spontaneously on earth (it may actually have been seeded from space naturally or intentionally, which is a whole other can of worms), and that the conditions on earth when life appeared were both necessary and sufficient. Neither of these assumptions may be true.

It may be conditions we deem necessary (i.e. the presence of water) are not necessary for life - only for "life as we know it" (life based on entirely different principles of chemical reactivity than what we experience on earth is a possibility - and the probability is equally impossible to calculate). And it may be the conditions on earth then were not sufficient in and of themselves - that some unknown anomoly (radioactive meteorite, who knows) was also required - and this would change the odds dramatically.

We're learning more about this question, very slowly, as we learn more about DNA and the mechanisms of life. Finding life on other planets in the solar system would similarly add information (which could nonetheless be ambiguous. A relatively terrestrial-like microbe from a moon of Jupiter might lead one person to argue that life will evolve in many places in a very similar track to the earth's - it might lead another to argue that this just proves that life was seeded from outside the solar system.)

While I would like to believe otherwise, I can't see intelligent (self-aware, technonogical) life being too common. Hope I'm wrong.

No way to calculate with only one point. But seeing as how it took about 3.5 bilY to get to us and if ol' earth has about 0.1-1.0 bilY left for life, our best-studied example says it takes a looong time. Maybe too long.

Maybe our best hope is to put some life elsewhere.

I agree. I think there might be intelligent life elsewhere but not as common as one might think. I'll be glad to be wrong on this one. One of the things that make me pessimistic is that fact that if intelligent life was common I would presume we'd see or hear something out there.

One possibility offered by an author is these "aliens" are mutated earthlings descendants from other species and humans ...sounds weird but.
Earth is the origin of intelligent species forced in exile on other stars planets systems long time ago.
Note than I don`t necessery agree with the author.Food for thought.

http://eaglenet.enochgraphics.com/dulce/O-LEVESQ.html

http://eaglenet.enochgraphics.com/dulce/

I remember the Dulce legends from my hard-core UFO debunking days. Besides the obvious reasons, I never believed that our gov't was "double-crossed" by scheming aliens that share an underground facility with us. A race capable of coming here doesn't need subterfuge to do us bad. It would make a good sci-fi movie though ... speaking of 'food for thought ' I remember reading about alternate intelligent life that might be unrecognizable to us, such as crystalline-based entities or exotic creatures like intelligent gas-bag type things that would live in a Jupiter-like atmosphere (I think it was Arthur C. Clarke that brought up the gas-bags in one of his novels). This could be one way intelligent life might avoid our detection I suppose. "Blimps" that think would take some getting used to! There's also the possibility of an aquatic-type culture (I'm playing "devils-advocate" against my earlier post it seems .. but, you'll have that!)

Lets continue that sci-fi movie....
The art of invasion.
http://www.humanunderground.com/archive/mj12.html

http://www.geocities.com/hyperdigm/tunnels.html
What is it? a space rocket?