Are we alone in the Universe?

[Aonz]

This of course is open to speculation; I'm just interested to know your opinions. Here are a few details about the Universe. 1) There are some 100 billion galaxies visible to modern telescopes and the total number in the universe is believed to exceed this number. 2) The total number of stars in the universe is roughly 10 billion trillion. 3) If one in a million stars has 1 planet that is roughly 10 million billion planets in the universe. 4) Dr Norman Murray, from the Canadian Institute for Theoretical Astrophysics has estimated there are 50 billion Earth-like planets in our own Milky Way galaxy.

[woodpam]

I've just finished a book called Other Worlds by Michael D. Lemonick. It's not particularly easy to read unless you have a sound knowledge of modern science, especially Cosmology, but it's fascinating and worth the effort. It is harder for me to believe that we are alone in the Universe than to believe that we are one of a number of life forms.

[Gef]

Given the huge scale of the Universe I would very much doubt if we are alone.

[anthomson]

Just because a planet is capable of substaining life does not mean it will necessary have life. Although evolution works great once it gets going - actually kicking it off in the first place may be very difficult indeed. Assuming that it will happen on other planets just because it happened here seems to me fundamentally wrong - you can't make good statistical predictions from a single piece of data - it could be we are just very, very lucky.

[thealien]

greetings, I found this site when I was searching the multinet using www. askneeelix.com. You are definitely not alone in the universe. Me and the wife, the three kids and the pet targ are here with you.

[woofgang]

God has asked me to say that she is here too

[treaclefight]

my standard answer to all these type of questions is that in an infintite universe, everything becomes inevitable, even the loch ness monster

[anthomson]

treaclefight's viewpoint was shared by Scientfic American last month : http://www.sciam.com/article.cfm?colID=1&articleID
=000F1EDD-B48A-1E90-8EA5809EC5880000 It does make the assumation that the universe is infinite and more or less uniformly filled with matter - not sure how they know this ?

[Gef]

I think anthomson has posted the most sensible answer so far. Probability (as most people understand it) suggests that there are many "Earth's" out there. However, there is no statistical evidence to support this view. Earth just happens to be the optimal distance from a particular type of star so it's generally not too hot or too cold for life. Its gravity is strong enough to keep its atmosphere intact but not so great to crush potential life-forms. Its period of rotation also prevents it getting too hot or too cold (in general) and its orbit is not so elliptical that the extremes of winter and summer endanger life. There are so many factors to consider and that is what makes it such a fascinating question. Irrationally I still beleive my previous answer. By the way, I see that woofgang believes that there are two Gods - one male and one female :-)

[xyzzy@bok]

I think...
There are infinitely many 'parrallel universes' that have Earth like planets with people with the same appearance, name and memories as you, who play out every possible permutation of your life choices. There is probably even one exactly identical to ours in every respect except that they spell parallel differently :-)
And if there was such a thing as time travel, or parallel crossing, it would by definition have already been done, so there isn't - unless that explains ghosts, and stuff. Likewise if there was an intelligence high enough to cross these great distances that would have been done already too. So in my opinion we are all too far away and a visit is not possible and Dog new this when he made the blueprint. And that sequence at the end of "name escapes me", movie with planet in Orions belt, where Orion is the cat, that end sequence where the planets' spinning and zoom out, out, out till you see it's really a collossal being playing marbles.. that sequence, what movie was that?

[Aonz]

To Anthomson and Gef: surely if life can exist miles below the oceans surface in water that is superheated by hydrothermal vents and where sunlight never penetrates. It is not unreasonable to assume life will exist elsewhere in this universe. To xyzzy@bok: The possibility of us ever encountering intelligent life if another matter entirely and if there are intelligent civilisations out there capable of space travel, what makes you think they would want to make contact with a violent and primitive species?

[woofgang]

I think that when you are thinking about God, gender is irrelevant, but "it" sounds a bit rude so I use either

[treaclefight]

my theory does all depend on the universe being infinite, but i cant see why matter needs to be uniformly spread out, in fact when we look at galaxies etc it seems that the universe is clusters of matter and not uniform at all. there's no spiritiuality and harldy any opinion in my answer, it just is logically true that if the universe is infinite everything becomes inevitable....infinte means the most obscure stuff will be happening somewhere...believe me, i only have to open my front door to see it most days. lately i want to question whether the universe is infinite though, but i think i should put that up as a separate question.

[woodpam]

To answer Gef's point about the Earth having the optimum conditions to support life - I understand that earth's gravity is not fixed and that the magnetic field around it actually reverses over enormously long variable periods of time. Our atmosphere is tiny in proportion to the earth's mass and changing in it's make up all the time. Life on earth seems able to cope with a large number of variables in our planet and perhaps evolution has equipped us to adapt to these changes. There is no reason to believe that any other planet's life forms would not have this ability.I am not an expert in this but am aware that we know very little about Earth and how it affects the life forms it supports. It took 15 years for drilling beneath the surface of the planet to get proportionally as far as breaking the skin on an apple so its ni wonder our knowledge is so limited.

[football]

http://www.seti-inst.edu answers part of this one. Is it Radio Cosmology or is it a hoax?

[LeMarchand]

A scientist by the name of Fermi has postulated that we could well be alone, as given the age of the universe other races (if they exist) should have started expansion out from their home worlds, and that we should have been able to detect some evidence of this (if only in the form of radio waves). Try a search for "Fermi Paradox" for more info.

[anthomson]

We don't even know how life begun on Earth - we still don't really have any idea how molecules could combine in such a way as to start replicating themselves. It has only happened once here on Earth and cannot be reproduced in the lab despite all our knowledge of RDA and DNA. That being the case it seems unscientific to start making predications about life starting elsewhere in our universe.

[anthomson]

I think the only way we can statistically 'prove' life elsewhere is by calculating the probability that an exact or near exact copy of earth and its history exists elsewhere. For this to happen I would guess we would be looking outside of our own universe because although its big it is finite (see treaclefight's posting on Infinite Universe. )