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Wed 4 Aug, 2004 12:51 am
With all the billions of stars in our galaxy, and the billions of galaxies in the universe, it seems probable that there is other, intelligent, forms of life 'out there.' But how many might even come close to resembling us?
Think about it: Earth is something like 4.7 billions of years old (if I'm not exact on this point, please correct); but: how many planets have a moon stabilizing a planet's orbit, as our Earth and Moon? Without a moon, placed EXACTLY where it is, would oceans still have tides? With the type of sun we have, how many planets are the same distance away, forming a variance of temperature like Earth? How many planets possibly possess the same 23% tilt that Earth does, making a much larger portion of the surface inhabitable with the presence of seasons, allowing life to evolve as it has?
How many planets have a similar sort of land mass, and plate tectonics, allowing ocean currents to regulate weather, as Earth does? Or the sort of atmosphere that developed on Earth, based on the ability of plants and trees existing on large land masses to convert carbon dioxide into oxygen? At the rate it does to support human life? And the temperature variance (of what, 120 degrees?) to support human life?
And then there is the whole evolution thing (not to irritate those who believe in Creation, but staying with my original thought). Would mammals have developed like they have if a comet had not hit the Yucatan peninsula 63 million years ago, changing the Earth from an environment favoring reptiles and dinosaurs to one favoring mammals? And from that, would the condition of fauna allow primates to evolve, as they did on Earth?
And that brings me to Time: What are the chances of all of these conditions being not only met, but being met RIGHT NOW somewhere else? How much has the occasional comet set back life on Earth? Or speeded it up? The point being, what are the odds that another planet has met all of these conditions, and are now in the same 10,000 year span as we are?
There surely must be other life somewhere in the universe, but what are the odds that something looking like us is really out there?
I was going to post this on the Science forum, but this seemed to actually be a better place...
What you just wrote is all expressed in the Drake equation:
http://www.space.com/searchforlife/seti_drake_equation.html
The space.com SETI pages are a great place to learn more:
http://www.space.com/searchforlife/
Seems there might be life on Mars after all:
http://www.space.com/scienceastronomy/mars_microorganisms_040803.html
Question is where life originated, here, or Mars, or both or even somewhere else...
Thanks for the reply. I'm familar with the Drake equation, but I believe that is meant for any society able to communicate via radio waves?
I'm actually interested in the possibility of any 'human' (primate) intelligent life. You know, somebody who kind of looks like us.
Drake allows for even non-carbon based life, I believe....
Yeah, you're right, but I guess it can be modified.
I find it almost unthinkable that we're the only intelligent life out there.
Re: Are we alone in the universe? Maybe so.........
A Lone Voice wrote:There surely must be other life somewhere in the universe, but what are the odds that something looking like us is really out there?
Given the diversity of life on this planet alone, even with the common foundation of DNA, it seems wildly unlikely that anything extraterrestrial would resemble us.
This is one of the things that is so disappointing about most sci-fi, and so revealing about alien abduction claims. The tendency to portray aliens as anything even remotely human seems both uncreative a unconvincing.
rosborne979,
evolution is a slow process, but it tends to find very efficient and ways of doing things.
like an ant colony that explores in a seemingly random way, the pheromone trails are selected for and this will allow the colony to very quickly find the most efficient route to a food source.
statr this experiment over as many times as you like, and they will converge on the same result.
this is essentially evolution, and we model it in computer science with genetic algorithms.
evolution of a species is fundamentally the same, and it is highly probably that given the same conditions, a species will evolve the same way.
certainly, on a different planet, conditions would be different...and not everythign would go exactly the same...but this does not mean evolution will find a COMPLETELY different path.
Lone voice
Unless something VERY strange is going on, life on other planets duplicating life on earth is not possible.
On the other hand, life may be widespread and even life that we would understand as intelligent might be common, if the search area encompasses the whole Universe.
What troubles me is not that intelligent life may be out there, but why as we look around, don't we see any?
Why don't we see any? Because it is very small.
Quote:Unless something VERY strange is going on, life on other planets duplicating life on earth is not possible.
I hope everyone else realizes why this sentence has no meaning.
Quote:What troubles me is not that intelligent life may be out there, but why as we look around, don't we see any?
...because we can't see billions of light years away through space with our eyes.
As someone posted on another thread:
Sometimes I wonder if there is intelligent life on earth.
Quote:...because we can't see billions of light years away through space with our eyes.
Thats funny, what are those little pinpoints of light outside my window right now? They appear to be stars, some of which I'm sure are many many light years away.
[I meant see as in detect, you know with a radio telescope array as in SETI etc.]
stuh505 wrote:evolution of a species is fundamentally the same, and it is highly probably that given the same conditions, a species will evolve the same way.
Conditions are never the same, and even the slightest variations have cascading effects, further reducing the probability of convergence.
The mere diversity of life on this planet, from bacteria to plants to fungus to insects to sharks to zebras, all within the biosphere of a single planet, all built from the same molecule (DNA), all related, should be sufficient indication of the variability inherent in the process (evolution) to convince anyone that we will not likely find any extra terrestrials with much similarity to us.
Steve (as 41oo) wrote:What troubles me is not that intelligent life may be out there, but why as we look around, don't we see any?
This is the Fermi Paradox. Fermi thought that if there was technologically intelligent life out there, that we should see it. And the fact that we don't, indicates that there isn't.
The Fermi Paradox Thread is here:
http://www.able2know.com/forums/viewtopic.php?t=24595&highlight=
Ah, but Ros, Fermi had not considered the Stuh505 paradox, that our eyes are not powerful enough to see very far into space, even if there was a little green man with a flag waving it.
Steve (as 41oo) wrote:Ah, but Ros, Fermi had not considered the Stuh505 paradox, that our eyes are not powerful enough to see very far into space, even if there was a little green man with a flag waving it.
Yes. Well, I guess we're gonna have to start re-writing all the books now...
If intelligent life was advanced enough to cross hundreds of light years of space, would they want to contact us?
Why?
"Hey, lets go see how those humans are doing?"
Why wouldn't they?
If we could visit them at minimal cost, wouldn't we want to do so? Wouldn't we be just a little curious about another intelligent life form? To see how they were coping if nothing else, with life?
Of course our inadvertant shout into the rest of space is still only a bubble about 90 light years in diameter. But its too late to recind it. If you believe intelligent/technological life is out there, we might have taken the biggest gamble of all time without even knowing it.
Quote:Thats funny, what are those little pinpoints of light outside my window right now? They appear to be stars, some of which I'm sure are many many light years away.
[I meant see as in detect, you know with a radio telescope array as in SETI etc.]
you must be joking, right? we just barely figuring out what's on Mars, and that's practically on top of us. even if we could see 10 billion years away, and there were a million planets in our direct line of sight that had intelligent creatures, and somehow we knew which planets contained intelligent creatures just by looking at the planets...even then, the chances of us finding them would be slim to none because we wouldn't know where to point the telescopes.
Quote:Conditions are never the same, and even the slightest variations have cascading effects, further reducing the probability of convergence.
The mere diversity of life on this planet, from bacteria to plants to fungus to insects to sharks to zebras, all within the biosphere of a single planet, all built from the same molecule (DNA), all related, should be sufficient indication of the variability inherent in the process (evolution) to convince anyone that we will not likely find any extra terrestrials with much similarity to us.
may I call you Mr.Science, because you seem to speak for the entire scientific community, and you have obviously worked a lot with genetic algorthms.
Quote:If intelligent life was advanced enough to cross hundreds of light years of space, would they want to contact us?
Why?
"Hey, lets go see how those humans are doing?"
1) I don't know whw the subject of alien life always makes people think of aliens visiting Earth. Aliens visiting Earth is highly IMPROBABLE for the same reasons that their existence is PROBABLE.
2) Who says that being super-intelligent allows them to travel the speed of light, or implies they want to spend millions of generations cramped on a tiny spaceship for no reason, going in some aimless direction?
3) Other intelligent creatures probably WOULD want to find other intelligent aliens...simply out of curiosity. Humans obviously do. But thats not going to make it happen.
Quote:1) I don't know whw the subject of alien life always makes people think of aliens visiting Earth. Aliens visiting Earth is highly IMPROBABLE for the same reasons that their existence is PROBABLE.
2) Who says that being super-intelligent allows them to travel the speed of light, or implies they want to spend millions of generations cramped on a tiny spaceship for no reason, going in some aimless direction?
3) Other intelligent creatures probably WOULD want to find other intelligent aliens...simply out of curiosity. Humans obviously do. But thats not going to make it happen.
This seems to touch on my original post; do we really know what the motivation of an intellegent, alien species might be?
Humans evolved as omnivorous mammals, slightly leaning to being carnivorous. Like many other mammals, primates (which we essentially are) tend to attack or even kill other primates that invade their territory. Other male mammals, such as the big cats and primates (again) will kill the young of other competing males if given the opportunity.
This is how we evolved.
I don't think we have any idea of what the motivation of an alien life might be if we contacted them, or they learned of us.
Quote:Of course our inadvertant shout into the rest of space is still only a bubble about 90 light years in diameter. But its too late to recind it. If you believe intelligent/technological life is out there, we might have taken the biggest gamble of all time without even knowing it.
Outstanding observation, Mr. Steve! This is also what I was planning on getting to in this thread. Again, it goes with my observation that we really do not have
ANY idea of how other life might have evolved.
And I'll say it again: I believe there is little chance that it evolved to look like us...
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