Is there life out there?

[ZappBrannigan]

I consider myself to be Mr. Skeptical, especially here in Hollywood, land of dog psychics and Shirley McClain. But there's one area of, I guess, astronomy (biology?) where I have what may be considered an irrational belief:

I think the universe is teaming with life.

And by life I mean the kind of life that we would recognize as such immediately, either under a microscope or when it steps up to us and says, “Hello.”

Now, I don’t think aliens have ever been to Earth, partly because of Carl Sagan’s explanation of how space-faring species might never meet, and partly because by this point, they’ve intercepted our transmissions of Gilligan’s Island.

But I do think someone, maybe lots of someones, are out there. Heck, I’ve got Seti@Home running on my computer.

I wanted to find out what other people on this board, many with lots of letters after their names, think about the possibility of life “out there.”

(Oh, and I had a more granular set of poll options, but one is only allowed five.)

[Glom]

I voted simple life because I'm pretty sure that there is plenty of simple life out there in some form, although to date, I do not know this as no evidence has been found, direct or indirect. I'll hedge my bets with the other ones.

If I may say, the last option is a bit insensitive to those going through a breakup. :P

[frenat]

I voted for simple life but I do believe that more complex life does exist. I don't believe that we will ever make contact. Why? Well think about the vastness of space and the age of the universe. More complex life will certainly be rarer. Strike one. The vast distance between stars and galaxies makes it less likely that any other life will be found because it takes to long to travel and combined with the increased rarity, it is extremely unlikely we could just go to the "next star over" and find complex life there. Strike two. Finally, with the age of the universe, other civilizations could have grown and dies out long before life even started to develop here. Strike three. So what are the chances we could travel somewhere within a reasonable distance, find these more rare complex organisms and that they would happen to be thriving at the time we decided to show up? Pretty slim I'd say.

[A.DIM]

I voted for simple life but I do believe that more complex life does exist. I don't believe that we will ever make contact. Why? Well think about the vastness of space and the age of the universe. More complex life will certainly be rarer. Strike one. The vast distance between stars and galaxies makes it less likely that any other life will be found because it takes to long to travel and combined with the increased rarity, it is extremely unlikely we could just go to the "next star over" and find complex life there. Strike two. Finally, with the age of the universe, other civilizations could have grown and dies out long before life even started to develop here. Strike three. So what are the chances we could travel somewhere within a reasonable distance, find these more rare complex organisms and that they would happen to be thriving at the time we decided to show up? Pretty slim I'd say.

But you're imposing our "human" understanding of physics and such on said "intelligent life" - should this be done? I don't think so. Especially considering that Earth and its "intelligent life" have been around a mere 4.5billion years (well, "intelligent" life is much younger and certainly the "intelligent" part is debatable :P ) and the Universe, as we know it, is much older.
So much for the Drake Equation, eh?

[waynek]

Back in grad school we had the asignment once to estimate the number of intellegent species in the galaxy using the Drake equation (see http://www.wikipedia.org/wiki/Drake_equation for the uninitiated). Most of the numbers are pure guesswork, but it helps to quantify an individuals guesses. Without premeditating the answer, I estimated (guessed) all of the variables and came to my particular result - exactly one (us). I therefore conclude that we may well be the only ones at the current time in our galaxy. At least this answer satisfies the Fermi Paradox ( http://www.transhumanism.ndtilda.co.uk/Fermi.htm ). I voted for simple life, although I'm not convinced that even that is all that common. We just don't know enough about that leap from amino acid soup to life to really say how easy it is. There are likely enough places for it to have a good try, though, that I won't go so far as to agree with the first choice.

[David Hall]

I've heard it said that the Drake equation is not so much a tool to calculate the existance of life, as a way to organize our ignorance about the subject. The answer is only as good as the estimates we put in to it, and those right now are mostly pure speculation. All it really does is give us a handle on what factors need to be considered.

[tracer]

There's an option missing from the poll:

"Very simple life exists on a few other worlds, but even it is rare."

That's the option I would have chosen.

[dgruss23]

JS Princton and I had a rather lengthy (and perhaps obnoxious to those that endured reading it) debate about this starting about here .

I agree with David Hall that the Drake equation provides us with a handy tool to organize our ignorance. I put down simple life may be common. I think that complex ecosystems are probably hard to come by.

[DStahl]

Hmmm. I too put down that simple life is common, but...

If simple life is common then no matter what environment it started in would not an evolutionary principle immediately come into play? And would that not lead inevitably in the direction of a complex ecosystem and increasingly complex lifeforms?

[dgruss23]

Hmmm. I too put down that simple life is common, but...

If simple life is common then no matter what environment it started in would not an evolutionary principle immediately come into play? And would that not lead inevitably in the direction of a complex ecosystem and increasingly complex lifeforms?

I think it depends on how the planet evolves. Take Mars - evidence is there that it probably once had liquid surface water. But today it obviously doesn't. So if life evolved on Mars, it could theoretically still exist as extremophile life in underground rocks - similar to what is found on Earth today. So I can see simple life being common, but the persistence of conditions that would allow that simple life to evolve into complex surface ecosystems might be much less common because some sort of climatic stability would seem to be necessary to maintain the surface liquid. That was the part where JS and I had severe differences of opinion. Obviously there's not enough data at this time to know for sure.

[DStahl]

Ah, good point--long-term stability of the environment could be pretty important. I'll have to look up that thread; it must have been one I missed.

[waynek]

Well, I certainly didn't intend to imply that the Drake equation was anything more than a tool for organizing our ignorance, only that my particular experience with it was that the idea that we are the only inteligence in the galaxy is just as plausible as a larger number.

tracer's missing option is the one I would have voted for if it had been there.

I haven't read the thread on long-term stability, but that is definately part of my thought process regarding simple life vs. complex. "Habitable zone" planets may be common enough, but the Earth seems particularly well suited for stability, including a large moon thought to have come about by a very improbable event (planetary collision). I thing of the almost infinite variety of possible planetary conditions there are very few so perfectly suited.

[frenat]

What if very simple life evolved but evolved in such a way that anything more complex would be immediately extinguished? Evolution then might never progress beyond the very simple stage.

[RafaelAustin]

I voted for simple life also. I think that once started, life is very tenacious and can exist in very harsh conditions. But unfortunately I think that most places are simply too harsh for complex evolution to reach higher levels. I posted a list recently of all the astronomical factors I could think of that make Earth habitable for humans. And after looking at that list, they seemed to be rather rare or even unique. Granted life elsewhere doesn't (or shouldn't) have to fit our mold. But the circumstances that brought us here are pretty special.

So I vote for billions of interesting petri dishes, but few zoological gardens and very few gardeners at all.

[dgruss23]

I voted for simple life also. I think that once started, life is very tenacious and can exist in very harsh conditions. But unfortunately I think that most places are simply too harsh for complex evolution to reach higher levels. I posted a list recently of all the astronomical factors I could think of that make Earth habitable for humans. And after looking at that list, they seemed to be rather rare or even unique. Granted life elsewhere doesn't (or shouldn't) have to fit our mold. But the circumstances that brought us here are pretty special.

I agree with your view. Hey where is that list posted?

So I vote for billions of interesting petri dishes, but few zoological gardens and very few gardeners at all.

That's a neat analogy. Do we rate as gardeners?

[A.DIM]

Nevermind the Drake Equation; only last year another statistical analysis increased the odds:

http://www.newscientist.com/news/news.jsp?id=ns99992283

And then this year:

http://www.newscientist.com/news/news.jsp?id=ns99993223


Yeah, I think we're being desensitized to the idea so that when they finally come out and say "We found'em!", most of us will go, "I knew it!"

[RafaelAustin]

I agree with your view. Hey where is that list posted?

Requirements for Interplanetary Life

[NubiWan]

Well, went with "common simple life" too, although being from Vegas, would expect there to be higher more complex life as well. Play the odds and see what you think... 8)

[nebularain]

I wanted to vote, but to do so I'd have to make a commitment. My stance is "It's possible there is some form of life out there, but it is also possible there is not." How do you vote that? :-?

[Archer17]

I voted for "simple" life. I'm not ruling out intelligent life somewhere out there but I don't think there's any in our immediate galactic neighborhood, at least not intelligent life as we know it. I base this on the presumption that we would've picked up at least something, somewhere, with SETI-type monitoring by now. Isn't some of our stronger EM transmissions a decent amount of light years out already?

[pmcolt]

I have this feeling that "simple" life will pop up anytime you have some interesting puddles of goop and a few million years of good conditions. I'm just not sure how often it ends up wriggling out, growing limbs and a brain, and sending out expeditions to probe farmers from nearby races.

[A.DIM]

This out a few days ago:

http://news.bbc.co.uk/2/hi/science/nature/2941826.stm

Claims have re-emerged that the US space agency (Nasa) did find signs of life on Mars during the historic Viking landings of 1976.
Dr Gil Levin, a former mission scientist, says he now has the evidence to prove it, just days before the US and Europe send new expeditions to the Red Planet.

So, it seems at least 60% of us are correct. :wink:

And why is NASA not looking for it during this mission?
I'd say because they already know.

[TheWatcher]

Common sense should tell everyone there is life out there. How primitive we will seem to the coming generations. They will ask themselves, how on earth (no pun intended) could those humans believe they were the only beings in the universe. How egotistical and naive!

You scientists that scoff at the earth-centric theories of old and the flat-world thinkers; don't you morons realize that we will be scoffed at in the same way?

Wake the ^$%% up! We are not alone, never have been. The universe is teeming with life and we are relatively primitive. There must be civilizations hundreds of thousands or millions of years more evolved than us.

Instead of debating the silly notion that we are alone, we should be getting ourselves ready for inclusion in a higher society. Right now we are as aboriginals to those civilizations that have achieved interplanetary travel. They don't want to interject their norms and ideals and society on us anymore than we do to aboriginals.

We must become more civilized before they will make themselves known to the masses.

This conclusion is the most logical and probalistic. The notion that we are alone is about as logical as thinking that the world must be flat or else everyone would fall off. And you thinkers that think that we are alone or that there is only microbial life out there, are the exact same people that hold us back from making the important discoveries. You are clinging to the security of the known and staying with the mainstream rather than risk being ridiculed. And you don't even know it.

You cling to your belief systems, until someone PROVES it to you, then you say you knew it all along. You deride those with different views than your own rather than facing them with an even mind.

Would you mind explaining why you think that the Earth alone is populated out of the trillions of trillions of other planets?

[Glom]

First of all, we are schooled in the ways of the Jay. We don't assume there is intelligent, advanced life out there. We suspend judgement.

Why? Because it's scientific.

Having a null hypothesis that the universe is teeming with intelligent, advanced civilisations that we simply haven't found is not falsifiable. As we continue to lack evidence of it, we just say that there just somewhere else. The hypothesis is not falsifiable and therefore not valid as a null hypothesis.

Assuming that no other life exists however is falsifiable. It is falsified when we find such life, which we think is rather likely. Hence, it is a valid null hypothesis.

Falsifiability is at the heart of the scientific method.

But, to use the null hypothesis that there is no life beyond Earth also entails a proposition. We have not been "everywhere" so we cannot offer supporting evidence for our hypothesis. Therefore we suspend judgement.

There have been some expressions that the poll is not that fair because it forces us to take up the position of proponent when we have no evidence to back up our proposition. We like to be scientific and that entails suspending judgement about the existance of extra-terrestrial life. The votes in favour of only simple life simply reflect the evidence we are likely to find in our life times. In a few years time, we may very well have the evidence for simple life in the solar system. But the evidence of advanced civilisations may be a long time down the road and hence, as scientists, we are suspending judgement and choosing not to get too wild, whatever statistical probabilities say, with our propositions.

Second, we may find civilisations more primitive than ours as well. We could be in the middle of the evolutionary chain. Who knows? We have no evidence. We're suspending judgement.

[Pluto is a planet]

Ok, lets say Mars did have running water in it's past. Does that necessarly mean there was once life there?

[Glom]

Ok, lets say Mars did have running water in it's past. Does that necessarly mean there was once life there?

No, it doesn't. Similarly, an absence of water, while pretty much negating the possibility of life as we know it evolving, does not prove that no kinds of life could evolve.

But, logically, we have no evidence for these "other" types of life forms, so we suspend judgement as to their existance and just go looking for Earth-like life. Anywhere with liquid water is a good place to start.

[ToSeek]

Ok, lets say Mars did have running water in it's past. Does that necessarly mean there was once life there?

Well, in the only sample space we have so far (Earth), water => life. Wherever there's water, there's life, even in the coldest icecaps of the Antarctic. Wherever there isn't water, there isn't life. So it definitely improves the odds, at the very least.

[TheWatcher]

You say we have no evidence of extraterrestrials so therefore we will withhold speculation.

We have lots of evidence:

1. Ourselves here on this planet and the fact that we now know that there are lots of other planets; gee, most scientist didn't want to think that there were other planets until they saw stars move in response to something. Ok, so here we have evidence on life on planets ours, therefore, it would be logical to assume that there must be life on other planets.

2. Hundreds of thousands of credible eye witness testimony of persons that have seen UFO's. This is evidence of the first degree.

3. The pyramids are proof enough, oh yeah, I forgot, you probably still cling to the silly notion that they were carved and chiseled and built by humans. That hypothesis, fails the common sense test unfortunately, as does the idea that we are alone.

One does not need proof, when common sense is applied.

You have no proof of hardly anything scientific. Only eye witness testimony and conjecture.

Think about it, your entire atomic theory is just that, theory. No one can say how an atom is constructed. Yet, scientists cling to the atomic theory as if it is cast in stone. Yet, no proof has been shown. So why can't I make a reasonable supposition about life teeming in the universe with or without proof.

All of your scientific knowledge regarding the atomic theory, magnetism, electricity, gravity, big bang, light being made of photons, and almost all of your astronomical knowledge is pure guess work. No proof. Yet, you believe it.

We should accept the fact, well okay - educated guess, that the universe is teeming with life, that we are the fools who still act like fighting children amongst themselves. Scientists still arguing about this and that in the face of total ignorance. Each one wanting to be right and get their name lit up in fame and fortune.

Every scientist fighting tooth and nail for their latest theory, to be recognized above their brethren. Rather than cooperating with each other, they compete against each other. We have segmented our sciences and compartmentalized everything to such a degree, that we have hindered true research and new discoveries.

All because of the frail human ego.

My friends, we are not ready to know, and that is the sad truth.

So let's go back and start squabbling amongst ourselves as to whether or not we are alone, instead of worrying about substantive issues.

[frenat]

A UFO is not necessarily an alien craft. It is simply something unidentified. Why are there not a lot more UFO sightings by amateur astronomers? They look up in the sky much more than many other people. If these UFO sightings were credible, then most of the sightings would be coming from amateur astronomers. Instead, an astronomer can identify the planet Venus or an airplane whereas casual observers have been known to misidentify the moon. And no, I'm not kidding about that last one.

Why do you you think most scientists didn't want to think that there were other planets? Do yo have a reference for that? I think most assumed other star systems would have planets as well but until recently they remained undetected.

Finally, how can the pyramids fail the common sense test? You think man couldn't have built them? If so, where is a single tool that was left behind? Where is a single artifact made with exotic alloys or non-primitive materials? There is plenty of evidence to suggest that man could and did build the pyramids as well as more than a few credible techniques that have been discussed right here on this very bulletin board. Maybe you just don't give mankind enough credit.

Oh well, I know I'm not going to convince you anyway.
Time to stop feeding the troll.

[beskeptical]

You say we have no evidence of extraterrestrials so therefore we will withhold speculation.

We have lots of evidence:

1. Ourselves here on this planet and the fact that we now know that there are lots of other planets; gee, most scientist didn't want to think that there were other planets until they saw stars move in response to something. Ok, so here we have evidence on life on planets ours, therefore, it would be logical to assume that there must be life on other planets.

Agreed. Life on Earth is evidence life can exist.

2. Hundreds of thousands of credible eye witness testimony of persons that have seen UFO's. This is evidence of the first degree.

Eyewitness accounts are some of the LEAST reliable kinds of evidence.

3. The pyramids are proof enough, oh yeah, I forgot, you probably still cling to the silly notion that they were carved and chiseled and built by humans. That hypothesis, fails the common sense test unfortunately, as does the idea that we are alone.

I think the evidence is mounting for purely human intervention. Perhaps you are relying on outdated research?

One does not need proof, when common sense is applied.

Common sense comes from evidence one has accumulated over time. If one cannot go back and sort out which evidence supports the common sense conclusion one has drawn, chances are good the conclusion will be based on distorted evidence.

You have no proof of hardly anything scientific. Only eye witness testimony and conjecture.

Think about it, your entire atomic theory is just that, theory. No one can say how an atom is constructed. Yet, scientists cling to the atomic theory as if it is cast in stone. Yet, no proof has been shown. So why can't I make a reasonable supposition about life teeming in the universe with or without proof.

All of your scientific knowledge regarding the atomic theory, magnetism, electricity, gravity, big bang, light being made of photons, and almost all of your astronomical knowledge is pure guess work. No proof. Yet, you believe it.

I don't mean to belittle you here, but atomic theory and all the things you cited above are based on clearly observable evidence, not just conjecture. I think you may just not be aware of the science involved in understanding the evidence.

We should accept the fact, well okay - educated guess, that the universe is teeming with life, that we are the fools who still act like fighting children amongst themselves. Scientists still arguing about this and that in the face of total ignorance. Each one wanting to be right and get their name lit up in fame and fortune.

Every scientist fighting tooth and nail for their latest theory, to be recognized above their brethren. Rather than cooperating with each other, they compete against each other. We have segmented our sciences and compartmentalized everything to such a degree, that we have hindered true research and new discoveries.
All because of the frail human ego.

My friends, we are not ready to know, and that is the sad truth.

So let's go back and start squabbling amongst ourselves as to whether or not we are alone, instead of worrying about substantive issues.

Such a cynical view. I don't care to win any nobel prize for a scientific discovery. I'm happy taking it all in and waiting for someone to discover something else. And, I like sharing what I've learned.

What you are describing as science is not. It is human nature. We are a competitive bunch whether we are politicians, business persons, priests or scientists. And, not everyone is as extreme a competitor as you imply.