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ZappBrannigan
2003-May-27, 06:48 PM
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, ďHello.Ē

Now, I donít think aliens have ever been to Earth, partly because of Carl Saganís explanation of how space-faring species might never meet, and partly because by this point, theyíve intercepted our transmissions of Gilliganís Island.

But I do think someone, maybe lots of someones, are out there. Heck, Iíve 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 ďout there.Ē

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

Glom
2003-May-27, 06:52 PM
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
2003-May-27, 07:03 PM
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
2003-May-27, 07:21 PM
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
2003-May-27, 11:18 PM
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
2003-May-27, 11:34 PM
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
2003-May-28, 01:05 AM
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
2003-May-28, 01:38 AM
JS Princton and I had a rather lengthy (and perhaps obnoxious to those that endured reading it) debate about this starting about here (http://www.badastronomy.com/phpBB/viewtopic.php?p=80042#80042).

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
2003-May-28, 01:58 AM
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
2003-May-28, 02:05 AM
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
2003-May-28, 02:17 AM
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
2003-May-28, 03:12 AM
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
2003-May-28, 03:25 AM
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
2003-May-28, 04:45 AM
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
2003-May-28, 12:26 PM
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
2003-May-28, 12:45 PM
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
2003-May-30, 04:26 AM
I agree with your view. Hey where is that list posted?


Requirements for Interplanetary Life (http://www.badastronomy.com/phpBB/viewtopic.php?t=4570&sid=46ce3673996d676dc0bdae2e16d1c931)

NubiWan
2003-May-30, 11:42 PM
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
2003-May-31, 08:58 PM
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
2003-Jun-01, 01:06 AM
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
2003-Jun-01, 04:49 AM
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
2003-Jun-01, 11:44 AM
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. :D

TheWatcher
2003-Jun-01, 09:49 PM
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
2003-Jun-01, 10:02 PM
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
2003-Jun-01, 10:35 PM
Ok, lets say Mars did have running water in it's past. Does that necessarly mean there was once life there?

Glom
2003-Jun-01, 10:39 PM
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
2003-Jun-01, 11:13 PM
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
2003-Jun-02, 03:01 AM
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
2003-Jun-02, 03:27 AM
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
2003-Jun-02, 04:40 AM
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.

Glom
2003-Jun-02, 11:28 AM
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.

That is evidence life can exist and there is a high probability that is does. The object is not to prove that life can exist, but to prove that it actually does exist. We have no evidence that it does exist, just evidence that there is a high probability. Until we find evidence that life does in fact exist, we suspend judgement. Remember, working on the null hypothesis that ET life does exist but we just haven't found it yet is not falsifiable and therefore not valid.


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

There have been hundred of thousands of reports of unidentified objects in the night sky. None of these have been able to credibly discern that they are in fact alien spacecraft.

I am an amateur astronomer. I spend a fair bit of time watching the sky and have yet to see one. When I was younger, I was easily influenced by the pseudoscientific bilk and was interested in UFOs. I remember deciding to sight a UFO at some point. While walking through Pinner, I looked up for a second and thought I'd seen one. It was plane. But because I didn't know much about the sky, I was easily deceived. Now I know more, I recognise planes and planets.

It's rare for Enterprise to say something intelligent, but this line was important. "There is a difference between keeping an open mind, and believing something because you want it to be true."


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'm a Stargate fan. But I've also seen the BBC programme Pyramid (http://www.bbc.co.uk/history/programmes/pyramid/index.shtml). I have yet to see any credible evidence that the construction of the pyramids was beyond the capabilities of the humans of the time. In certain ways they were more capable than we are today. No unions. It was Maggie's dream time. There is always the Against the Mainstream forum if you wish to argue this point. It would be on topic, although it's probably been discussed before. Do a search first.


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

Sometimes common sense can be applied for the purpose of proof. But common sense is not a substitute for proof.


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.

Actually, X-ray and gamma ray diffraction have yielded much evidence in favour of the simple atomic model.

But more to the point, atomic theory down to the level of protons, neutrons and electrons, anything more detailed is most certainly not cast in stone, is accepted as fact because it so neatly predicts what chemists observe. There is evidence for the validity of atomic theory. The model explains the observations with great accuracy and reliability.

However, no observations require us to formulate the model that ET life does in fact exist. Such a hypothesis would not explain any observations. The observations currently would explain why ET life would exist but attempting to reverse that would be affirmation of the consequent, a criminal fallacy.


So why can't I make a reasonable supposition about life teeming in the universe with or without proof.

A lot of us also think that it is highly likely the universe is teeming with life. Scientifically, such a supposition wouldn't serve of any benefit as it wouldn't explain anything. The observations will tell the story.

Our confidence that we will sooner or later find ET life fuels the imagination with some great astro art (http://www.bbc.co.uk/science/space/spaceguide/skyatnight/proginfo.shtml). But a lot of us are uncomfortable with the idea of saying outright we believe such life exists without actual evidence, even if probability is on our side.


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.

Atomic theory is based on observations. Magnetism, electricity and gravity are based on observations. The Big Bang is a hypothesis supported by evidence (CMB, Cosmic Abundance, the expanding universe) but no proper scientific mind would say that it is cast in stone. Light being made of photons is a model that is based on observations and predicts other observations with great accuracy. Observations have led to these theories we believe. The hypothesis that life exists elsewhere in the universe is not based on observations. It's based on statistical probabilities and wishful thinking so far. Hopefully before long, we will have the evidence. Europa is awaitin'.


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.

Never underestimate the benefits of a little healthy competiton. It can inspire great and rapid progress. Periods of greatest technological advancement have come due times of war. Apollo is the result of competition.

A.DIM
2003-Jun-02, 12:23 PM
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. :D

Addendum:

http://news.bbc.co.uk/2/hi/science/nature/3010631.stm

TimH
2003-Jun-02, 02:22 PM
Slightly OT but... this thread reminded me several years ago there was a theory gaining some momentum that one of the moons of Jupiter, Europa, might have liquid water beneath an icy crust. Some jumped the gun and started to speculate there may be simple forms of life near fissures in the floor of Europa's oceans. It was all the rage on CNN's 'science' page at the time but given their recent run I may have to delete the above theory from my memory

I don't think this is the same article I read all those years ago, but I think it is similar enough http://www.msnbc.com/news/207504.asp

A.DIM
2003-Jun-02, 03:11 PM
Slightly OT but... this thread reminded me several years ago there was a theory gaining some momentum that one of the moons of Jupiter, Europa, might have liquid water beneath an icy crust. Some jumped the gun and started to speculate there may be simple forms of life near fissures in the floor of Europa's oceans. It was all the rage on CNN's 'science' page at the time but given their recent run I may have to delete the above theory from my memory

I don't think this is the same article I read all those years ago, but I think it is similar enough http://www.msnbc.com/news/207504.asp

I don't know about "all the rage," but NewScientist has had several items in the last year about this:

http://www.newscientist.com/news/news.jsp?id=ns99993421

http://www.newscientist.com/news/news.jsp?id=ns99992929

http://www.newscientist.com/news/news.jsp?id=ns99992313

ZappBrannigan
2003-Jun-09, 03:35 AM
You say we have no evidence of extraterrestrials so therefore we will withhold speculation.
I see a poll that shows 43 out of 44 board members think that thereís at least simple life out there (and I note Glomís point about the limited choices of the poll. I guess thatís why I asked ďDo you think.Ē) I actually got more-or-less the result I expected from this poll. I had assumed that scientists, amateur and professional astronomers, and their groupies (like me) thought, as a group, that thereís life out there. Of course, we have no proof.


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.
I donít think thatís true, either. I canít speak for the pros on this board, but I bet they all assumed (or believed, or whatever sub-scientific fact term you want to use) that other stars had planets orbiting them long before we actually observed any.


2. Hundreds of thousands of credible eye witness testimony of persons that have seen UFO's. This is evidence of the first degree.
There have been hundreds of thousands of Virgin Mary, faerie, succubus, and even dragon sightings, if you go back far enough in history. Iím not going to get into the first one, but I think itís safe to assume that the last three donít exist, despite the number of sightings. Also, hereís a thread (http://www.badastronomy.com/phpBB/viewtopic.php?t=5610) detailing my own alien sighting.


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.
On behalf of the ancient Egyptians, YUHUH! We did so build Ďem! Why is it that the pyramids are so impossible for humans to build when nobody has any doubts about who built the other Seven Wonders of the Ancient World?


Think about it, your entire atomic theory is just that, theory.
We donít understand atomic theory? Then exactly what are all those huge craters doing in the Nevada desert? What was causing all that background anxiety I had back in the 80's?


My friends, we are not ready to know, and that is the sad truth.
Iím ready. But Iím ready to know facts, and solid information, not strange stories about Earth being visited by aliens with a very alarming *** fetish.

(Sorry I said ďass.Ē)

foxd
2003-Jun-12, 07:50 PM
I think there are probably other intelligent beings in our galaxy, and some may have spread out across the galaxy, but that doesn't mean they have spread to every nook and cranny in the galaxy, which is what the Fermi paradox seems to imply. After all, we as a species have spread across the Earth, but there are certain places we prefer to live.

As far as picking up their radio broadcasts, it is a bit more complicated than tuning in their broadcasts of "I Love Zorblat!" What it comes down to, is that there are a series of trade-offs and assumptions about each other's receiving and transmitting equipment, which may or may not be correct. When mixed with an unknown drifting doppler shift for both parties, detection becomes very difficult.

I do think once a signal is detected, enough will be discovered about it to enable the detection of other such signals. (Also, there will suddenly be a lot of funding for the search.) Figuring out what the signals are for may be a problem, I don't really think they will be the Encyclopedia Galactica, more likely some beacon transmitting telemetry or the alien version of Gene Scott.

A.DIM
2003-Jun-16, 01:50 AM
I think there are probably other intelligent beings in our galaxy, and some may have spread out across the galaxy, but that doesn't mean they have spread to every nook and cranny in the galaxy, which is what the Fermi paradox seems to imply. After all, we as a species have spread across the Earth, but there are certain places we prefer to live.

As far as picking up their radio broadcasts, it is a bit more complicated than tuning in their broadcasts of "I Love Zorblat!" What it comes down to, is that there are a series of trade-offs and assumptions about each other's receiving and transmitting equipment, which may or may not be correct. When mixed with an unknown drifting doppler shift for both parties, detection becomes very difficult.

I do think once a signal is detected, enough will be discovered about it to enable the detection of other such signals. (Also, there will suddenly be a lot of funding for the search.) Figuring out what the signals are for may be a problem, I don't really think they will be the Encyclopedia Galactica, more likely some beacon transmitting telemetry or the alien version of Gene Scott.

Charles Townes was celebrated (http://www.space.com/searchforlife/charles_townes_030613.html) recently for his contributions to SETI.

What about laser beam (http://www.space.com/searchforlife/optical_seti_010724.html) transmission of info? Cool.

AK
2003-Jun-16, 02:15 AM
Ah, good point--long-term stability of the environment could be pretty important.

To a degree, depending on how much stock you place in catastrophism. Many would argue if the environment was too stable, there wouldn't be the kind of selection pressures you'd need to see dramatic evolution from simple self-replicating molecules to complex organisms.

eburacum45
2003-Jun-16, 10:31 AM
There probably has to be gradual environmental shift, so that previously continuous populations become isolated from each other by physical barriers.
Evolution seems to work best in these conditions.
This sort of medium level environmental change doesn't want to be too rapid, or even the isolated populations will become extinct.

Earth is a good place to evolve - yet to an extent the environment of Earth is regulated by the actions of life, so these conditions might not be so difficult to come by after all.

dgruss23
2003-Jun-16, 12:02 PM
Ah, good point--long-term stability of the environment could be pretty important.

To a degree, depending on how much stock you place in catastrophism. Many would argue if the environment was too stable, there wouldn't be the kind of selection pressures you'd need to see dramatic evolution from simple self-replicating molecules to complex organisms.

Just to be clear - by climatic stability I mean conditions that allow for the existence of all three phases of water. You can have ice ages and warm periods with no polar caps, but as long as water is capable of existing in all three phases then you have a relatively stable climate.

AK
2003-Jun-16, 01:15 PM
There probably has to be gradual environmental shift, so that previously continuous populations become isolated from each other by physical barriers.
Evolution seems to work best in these conditions.

This is known as allopatric speciation, and for a long time was considered the main vehicle for speciation. However, recent evidence has revealed a lot more sympatric ("same land"/same environment) speciation than previously thought, often due to niche specialization within these environments.

Glom
2003-Jun-16, 01:20 PM
This is known as allopatric speciation, and for a long time was considered the main vehicle for speciation.

We knew that. :o

AK
2003-Jun-16, 03:18 PM
We knew that. :o

Sorry, not trying to talk down at anyone, I was just clarifying in case there was someone who didn't know.

Glom
2003-Jun-16, 05:12 PM
Sorry, AK, that was an RDAism. It was a line O'Neill used in '1969' when he didn't understand Carter's explanation of the precautions she was taking with dialing out.

Stuart
2003-Jun-16, 05:25 PM
I put down intelligent life is common (although, having done so I thought about my last trip to Washington and doubts surfaced) . I have a hunch that its going to be one of those avalanche things - making the first contact will be hard, the rest will pour down.

NubiWan
2003-Jun-16, 06:26 PM
LOL The real question is, "Does intelligent life exists," huh, Stuart.
:lol:

Stuart
2003-Jun-16, 07:31 PM
LOL The real question is, "Does intelligent life exist," huh, Stuart.
Once inside the Washington Beltway, yes. A very good question. Probably the only being inside the Beltway with a grasp on reality is the Drunken Angel (inside joke for Washingtonians there)

Kebsis
2003-Jun-16, 07:41 PM
Well, as far as we know, all you need to produce life is water and reasonable temperatures. And thats just to produce life that is similiar to what we know on Earth.

All you need to produce intelligent life (intelligent as in, average mammal-level) is the above criteria and time.

Since I'm sure all those things exist within the universe in vast quantity, I'd imagine there are plenty of places teeming with life just like our planet. I voted 'Mammal-like life is abundant', because although I feel human-level or greater intelligence is also probably present in large numbers, I don't think that we've been visited or that we'll be making contact anytime soon.

And, anyone who says scientists aren't ready to know 'the truth' about aliens has their head on wrong. I'm not a scientist, but I consider myself scientifically minded, and I would love to be abducted by aliens. They could use whatever instrument they wanted on whatever orifice they wanted, the knowledge of their existance would be worth the price.

Emspak
2003-Jun-16, 10:33 PM
I didn't answer the poll, but there is a little math you can do to tease out the possibilities.

First, you have to work out the assumptions you make. We can only (thus far) detect anything like life that shows up at astronomical distances. That means it has to be broadcasting something. Anything, it doesn't matter. But our own TV transmissions cover a pretty wide spectral range. (Radio runs at the KHz range for AM all the way up to GHz for cell phones). Obviously these will all transmit differently over varying distances.

However, that said, if you were looking at the Earth from, say, 40 light years away, it would be one heck of a bright radio source, and far brighter in some wavelengths than the sun has any right to be. More important, anyone listening, even without any knowledge whatsoever of us, would be pretty clued in that this was no way a natural phenomenon.

OK, so why haven't we seen an aliens' "I Love Lucy" episodes?

Well, there is the time factor. We have only been transmitting for abuot 100 years -- and not in any quantity for more than 80 or so, and only had television since 1939. So anyone who hears it had to start listening sometime in the last 100 years, and has to hit the right frequency for that. The problem (for the hypothetical aliens) is made easier as time goes on, even though some frequencies won't get as far as others. But still, that puts a maximum possible radius anyone could hear us. Say 100 light year sphere.

Now, we could all blow ourselves to kingdom come tomorrow. Or a meteor could hit. Whatever. Point is, if we stop transmitting tomorrow, that sphere one can hear us in lasts for 100 years, and then that is it. Whoever is listening has to be doing so in the right time frame, which means they had to have developed a technical civilization at least around the same time we did. This time moves back the further away you go.

What it means is that the odds of hearing someone else are proportional to the amount of time that civilization lasts. It is also related to how far away it is.

So, if we wanted to detect a civilization 1000 light years away, they had to start transmitting radio signals -- even if it is just bleed from their own transmissions, like us -- 1000 years ago. They had to keep doing it long enough for us to be looking, so if they started transmitting 1100 years back and died out 50 years afterwards, and we didn't happen to be listening, tough luck.

We know approximately how many stars there are in the galaxy (about 100 billion or so). Most are clustered towards the center and in the spiral arms. But the furthest is about 100,000 light years distant, give or take.

So, if anyone is calling, they can't have started transmitting from the furthest place out less than 100,040 years ago or so, or we would have heard them. So we can pretty safely say that out to 100,000 light years in the areas of sky we've seen there is nobody transmitting, at least not from the local galaxy. Or more accurately, we haven't heard anyone who achieved the ability to transmit and kept it to within 100,000 years of our being able to hear them.

Now, this still leaves a lot of possibilities. It could be that nobody in that neighborhood has radios yet. No reason they should, either.

Or, they could have come and gone without our ever knowing (see above). There has been plenty of time for civilizations to come and go -- if they did so a million years back we'd never know.

So you have 100 billion stars spread out in a pancake 100,000 light years wide. How long does a civilization have to last for us to have a hope of hearing about it?

Well, assuming a random distribution, and assuming further we could examine closely 10,000 stars a year, they'd have to last at least 10 million years to hope they were in that lucky patch of sky we happened to spy on. That number goes down the more stars you can cover in a given time frame.

Assuming the stars were evenly distributed in a pancake 1/50th as thick as it is wide (they are not, I am doing this or simplicity's sake) that is 15.7 trillion cubic light years or an average of .006 stars per cubic light year -- about one every 150 cubic l.y. or so on average. Plainly this is not the actual distribution locally, stars cluster about but again, this is an average smeared out over an approximate volume. That puts the average distance between stars at 3-4 light years or thereabouts.

Now, they aren't all on every star, so really the average distance is much greater.

This means, basically, that while there possibilities for alien civilizations out there, we may well have missed them. But we know where (and when) they aren't, or can't be, assuming they use radios.

What if they don't use radios? Well, they might all be using phased neutrinos or smoke signals, or spinning neutron stars up and down to produce patterns in pulsar signals. We don't know. But you have to stat someplace, and granted the bias is to life forms that produce repeating signals.

eburacum45
2003-Jun-17, 12:03 PM
Advanced civilisations might be expected to use narrow beam communication- lasers in the visible wavelengths or shorter-
this means the amount of data communicated per joule is higher than by radio broadcasts.
(however the interstellar medium is less transparent to many short wavelengths- it is a question of looking for holes perhaps)
There might be a way of using quantum effects to increase the data transfer efficiency- quantum entanglement allows for quantum teleportation, which sounds wacky, but because it transfers information via classical channels, operates at the speed of light rather than instantaneously.
http://www.wikipedia.org/wiki/Quantum_teleportation
I would also suggest that subatomic wormholes are also capable of data transmission over long distances, and there would be no possibility of interception of such transfer.
So SETI are perhaps looking at the wrong wavelengths, and possibly looking for signals which are actually transmitted by channels impossible to detect between the sender and destination.

foxd
2003-Jun-17, 02:25 PM
The main advantage of lasers is that it is easier to focus them into a narrow beam. While this makes it easier to detect by the civilization it is aimed at, those off to the side of the beam would have a more difficult time detecting it.

It is possible that they use radio in an entirely different way than we do. For instance, there are recent developments to use guassian pulses, rather than carriers, to transmit information. A civilization that went the guassian pulse route from the start of radio development would be very difficult for us to detect.

http://www.ee.ucl.ac.uk/lcs/papers2002/LCS040.pdf
http://www.csem.ch/corporate/Report2001/pdf/page76.pdf

Emspak
2003-Jun-17, 02:56 PM
You are quite right, but I was assuming that they are not deliberately transmitting to us or anyone else. That isn't necessarily so either. Good point.

But I think the method I outlined -- and the one being used by SETI researchers now-- has the benefit of making the smallest possible number of assumptions.

There was an interesting article in Scientific American a year or two ago, about how life would be limited in time as well as space. There could be no life before the first few milion (maybe tens of millions) of years in the universe becuase you need elements other than just hydrogen and helium. That means second generation stars, so the oldest possible civilizations would have had to get their start, oh, say 10 billion years ago when the first sets of stable stars with lots of heavy (i.e Lithium and beyond) elements available appear.

So that means in our galaxy, you can't go back more than that. Still plenty of time for someone to colonize the rest of us, if intelligence is common.

But that time window drops when you realize that metallicity does matter- if there are too few heavy elements in a developing solar system you can't have complex chemistry and if there are too many you get big, heavy planets like Jupiter.

Maybe that is why we haven't heard? Everybody appears at approximately the same time, in cosmological terms.

foxd
2003-Jun-17, 10:29 PM
On earth we colonize where there is reason to colonize, such as trade routes and/or exploitable resources. I would think that aliens would have reason to do the same thing. While we view Earth as special, it may not be such a reasonable place to colonize, due to lack of exploitable resources that can get to market. This is one of the reasons I question the Fermi Paradox.

Vega115
2003-Jun-19, 02:56 PM
I look at it this way, as said in the movie Contact: "If its just us out there...It's an awful waste of space." 8)

eburacum45
2003-Jun-19, 09:24 PM
On earth we colonize where there is reason to colonize, such as trade routes and/or exploitable resources. I would think that aliens would have reason to do the same thing. While we view Earth as special, it may not be such a reasonable place to colonize, due to lack of exploitable resources that can get to market. This is one of the reasons I question the Fermi Paradox.

But what material goods would be valuable enough to trade over interstellar distances? Any element would be as likely to be found in all the other solar systems, any food or manufactured article would be cheaper to grow or construct at or near the point of construction.

As it happens, Earth has a greater variety of usable elements and minerals than almost anywhere else in the solar system, because of the geological activity mixing and differentiating the crust.

However if interstellar prospectors really want to cross light years to obtain metals and other resources it might be cheaper for to mine Io and the asteroids because of the lower gravity.

Glom
2003-Jun-19, 11:10 PM
But, if they're nice aliens, they might treat Io, as a part of our system, as our jurisdiction and so they would have to rent it.

A.DIM
2003-Jun-20, 12:25 PM
Seti Today (http://www.space.com/searchforlife/seti_astrobiology_030619.html) article out yesterday discusses current technologies and mindsets behind the search.

foxd
2003-Jun-20, 02:51 PM
But what material goods would be valuable enough to trade over interstellar distances? Any element would be as likely to be found in all the other solar systems, any food or manufactured article would be cheaper to grow or construct at or near the point of construction.


The elements in the material might be readily available, but the procedure for assemblying them into the desired product might be very difficult to figure out, due to the atoms and molecules needing to be added in a particular order.


As it happens, Earth has a greater variety of usable elements and minerals than almost anywhere else in the solar system, because of the geological activity mixing and differentiating the crust.

Of course, the argument could be made that they would have no need to trade for usable elements, since any they needed could be made from readily available protons, neutrons and electrons. I think the difficulty of assembly argument applies here too. Certain nuclear reactions are easier than others.

A.DIM
2003-Jun-25, 09:25 PM
More desensitizing (http://www.space.com/scienceastronomy/astrobio_tyson1_030625.html) for us. And chances are, they're like us. :o

sarongsong
2003-Jun-26, 07:18 AM
Yes, of course there is.
Did anyone see this Sci-Fi Channel presentation?
(I missed it)
"...The network will have the premiere of a documentary, "Out of the Blue," at 8 tonight [Posted on Tue, Jun. 24, 2003], that methodically lays out an argument that there's something out there..."
http://www.kansascity.com/mld/kansascity/entertainment/6151911.htm

eburacum45
2003-Jun-26, 08:58 AM
eburacum45 wrote:
But what material goods would be valuable enough to trade over interstellar distances? Any element would be as likely to be found in all the other solar systems, any food or manufactured article would be cheaper to grow or construct at or near the point of construction.

foxd wrote:
The elements in the material might be readily available, but the procedure for assembling them into the desired product might be very difficult to figure out, due to the atoms and molecules needing to be added in a particular order.
----------------------------

The procedure for assembly is really all that is required; if each interstellar colony has assembler technology, all that needs to be sent in most cases is the recipe for the item you want- from a glass of orange juice to a spaceship.

nebularain
2003-Jun-26, 01:58 PM
Did anyone see this Sci-Fi Channel presentation?
(I missed it)
"...The network will have the premiere of a documentary, "Out of the Blue," at 8 tonight [Posted on Tue, Jun. 24, 2003], that methodically lays out an argument that there's something out there..."

Yes, I saw it. You can see my evaluation here (http://www.badastronomy.com/phpBB/viewtopic.php?p=106217#106217) . For all the hype, it was the same-o-same-o UFO documentary I've seen many times before. I was disappointed. Nothing new, nothing more convining than all that's been before.

Manchurian Taikonaut
2004-Mar-19, 06:25 PM
it is a great idea, not to only we on this search for life, but to also detect the radio wave given off when sunlight falls on a leaf, it might also be possible that in another part of the galaxy some other life form has stumbled across UHF in the last 100 years, or is the galaxy empty?

Danny_Lpool
2004-Mar-23, 12:03 AM
surely by the laws of possibility, there has to be life out there, i refuse to belive that only us are here, in a universe thats bigger than we can even imagine there is life out there. this i would bet my left arm on that. (i need my right one incase i am proven wrong.....)

Brady Yoon
2004-Mar-23, 01:24 AM
I believe, like many others on this board, that intelligent life is fairly common, but the vast distances of space make direct contact almost impossible. I also think that the life will most likely be completely different from life as we know it.

makaya325
2006-Nov-26, 03:55 AM
i would say that simple life is common, complex life like fauna and plants certainly exist, only in small numbers. intelligent life capable of using technology are probably very rare, but given the size of the universe, even if they are rare, at least 1 other could exist

Van Rijn
2006-Nov-26, 04:04 AM
This is an old thread. Did this come up on the "similar thread" list? Hum, just noticed that the "similar thread" list seems to be gone.

greenfeather
2006-Nov-26, 04:32 AM
Since I'm sure all those things exist within the universe in vast quantity, I'd imagine there are plenty of places teeming with life just like our planet. I voted 'Mammal-like life is abundant', because although I feel human-level or greater intelligence is also probably present in large numbers, I don't think that we've been visited or that we'll be making contact anytime soon.

I almost voted for the Mammal-like life, but then I thought about how almost all the exoplanets they've discovered are gigantic hot Jupiters and other worlds which wouldn't work for Earth type life. Of course I don't rule out Jovian-type life, such as those big ol' gasbags & blimps. :D

Of course, there are a lot of those on Earth too... especially inside the Beltway!!!!!!!!!!:razz:

Apollo123
2006-Nov-26, 05:05 PM
The reason most of the exoplanets discovered so far are gigantic hot jupiters is because they are the easiest to find. Most astronomers think that the smaller the body is, the more there are of them. That rule works for stars, the biggest and hottest are the least common, the coolest red stars are the most common. They are finding more and more brown dwarfs, and the suspicion is, since these can also form independently of any star, that they are more common than the small red stars.

Applying the rule further, you would have Jupiter sized planets > brown dwarfs, Neptune size planets > Jupiter sized planets, Large rocky planets (>5x earth) > Neptune size, earth size > large rocky, mars size > earth size, pluto size > mars size, moons > pluto size? ... asteroids > moons or whatever we are going to call them ... meteriotes > asteroids , electrons > ... and putting them all in order you would have:

Large stars < medium stars < small stars < brown dwarfs < Jupiters < Neptunes < large rocky < earth size < mars size < plutos < moons < asteroids/comets < meteorites < dust grains < gas molecules < atoms < ...

So we can see from the rule, that there could be hundreds of billions of planets in our own galaxy alone, many of which could be in the mars to earth size, and many could be in the life zones of stars. Given the abundance of water and complex organic molecules that form in the universe, we have an abundance of life forming material, and an abundance of places for that material to settle. And that is just to produce carbon based life as we know it.

Scientists now think that water planets are probably common throughout the universe, because of the amount of water and the number of planets they are finding in places they didn't think they would find them. Even though most of the ones discovered so far are jupiter sized, many (other than the hot ones ) would probably have moons around them, so if that is case, and these moons are anything like the ones around Jupiter and Saturn, they probably have lots of water around them. Where there is water there is probably life and lots of it.

My first guess is the galaxy and universe are both teaming with life of all kinds, with the small single celled life forms being the most abundant, but with plenty of complex intelligent life forms as well. Even if the intelligent forms are rare compared to the smaller forms, there could still be a lot of it.

One qualification is that all life isn't just going to appear all at the same time, it will come and go as a planet and star ages, and eventually disappear as the planet and star die. It takes a long time to form a species as complex as a human being, so the chances of two intelligent species forming near enough to each other and in the same time period, and last long enough to be able to communicate with each other, and be both at a similar level in develpment (ie they recognize that something is attempting to communicate with them ) is probably very small, and probably very rare on a galactic scale.

My second guess is that we haven't been around long enough for our signals to reach any advanced civilizations, and in our whole galaxy, we could be the only civilization at this stage (just reaching the beginnings of the space faring stage) in development. Any other intelligence could be either so far beyond us in evolution and technology that we don't recognize it (if we survive, would we recognize ourselves in a million or billion years?, we probably can't even imagine or comprehend what we'll be like or what we can accomplish), too far away for our signals to reach each other, or any other intelligent life that exists now might not yet be at the point where it can even attempt to communicate interstellarly. We could be the only one in our galaxy capable of any kind of interstellar communication ... right now.

Also consider this: In the life cycle of a galaxy, there will be a first occurrence of intelligent life somewhere in that galaxy. There is always the possibility that we are that first occurrence. I consider that unlikely, given the age and size of our galaxy, but it is possible. If that is the case, then we aren't treating ourselves very well. We would be an extremely rare and important occurrence, and it should be our duty to preserve ourselves, and our environment. I mean maybe a galaxy only gets a few chances before it gets too old to produce intelligent life.

makaya325
2006-Nov-26, 08:50 PM
well we know that some fauna, like tubeworms and targinades, can survive extreme conditions, as well with other animals. so i think it could mean animal life isnt as rare as people might think. rare earth never points out that even tubeworms, which are multicellular, can survive in extreme conditions.

loglo
2006-Nov-27, 06:59 AM
well we know that some fauna, like tubeworms and targinades, can survive extreme conditions, as well with other animals. so i think it could mean animal life isnt as rare as people might think. rare earth never points out that even tubeworms, which are multicellular, can survive in extreme conditions.

I think the question that really needs answering is can life develop in extreme conditions? Did the ancestors of the current extromophiles develop where they live or did they just evolve into the niche from somewhere relatively benign? We know life is tough once it gets going, its the getting going that remains problematical, to us anyway.

greenfeather
2006-Nov-29, 01:47 AM
The reason most of the exoplanets discovered so far are gigantic hot jupiters is because they are the easiest to find.

Actually I was thinking of how there are so many of these hot Jupiters and how they're so close to their suns, that they probably prevent any Earths from forming in the habitable zone. That was what got me thinking maybe Earths are pretty rare.



My first guess is the galaxy and universe are both teaming with life of all kinds, with the small single celled life forms being the most abundant, but with plenty of complex intelligent life forms as well. Even if the intelligent forms are rare compared to the smaller forms, there could still be a lot of it.

I agree that the galaxy probably teems with all kinds of life. I also think that there could be many kinds of intelligences out there, who don't communicate with us because they don't use radio.

Frinstance I just read today on msnbc.com that humpback whales have a certain type of brain cell that humans have, which is thought to be a function of intelligence. Dolphins and chimps have this too.

I think we are way too human-chauvinistic about what constitutes intelligence. It's possible that life has evolved some sort of intelligence in many places, without evolving skyscraper-building, TV-watching aliens. It's even possible that ET's have better control of themselves than we do, and they have never overpopulated or polluted their planet.

Maybe they know about us, but don't want to associate with our kind of lowlife!

greenfeather
2006-Nov-29, 01:50 AM
I think the question that really needs answering is can life develop in extreme conditions? Did the ancestors of the current extromophiles develop where they live or did they just evolve into the niche from somewhere relatively benign? We know life is tough once it gets going, its the getting going that remains problematical, to us anyway.

Well, life on Earth began in extreme conditions, didn't it?

PhantomWolf
2006-Nov-29, 01:51 AM
Maybe they know about us, but don't want to associate with our kind of lowlife!

Oh I firmy believe that the New Horizons team is in for a shock when they photograph Pluto. I think they'll find a gigantic sign stuck in it reading "Danger, Humans next 15 Billion Kilometres. Keep Out!"

loglo
2006-Nov-29, 11:08 AM
Well, life on Earth began in extreme conditions, didn't it?

Only extreme for us, not for extremophiles, if I understand the latest thinking on origins of life (and I'm not an expert). I was referring to the >80C or sub-zero temperatures or ultra acidic/alkiline environments etc that are touted as possible places in the universe that life could have formed.

Saying that since extremophiles on Earth can survive such conditions then it is possible for life to develop in similar conditions elsewhere does not necessarily follow. If the base chemical processes necessary for the creation and development of simple lifeforms cannot exist in those extreme conditions then life cannot evolve in such environments but only adapt to it from elsewhere after evolving more robust chemical reactions.

My personal hunch is that life needs a relatively benign environment to actually start so all life bearing planets would have had a "warm wet" period at some point.

greenfeather
2006-Nov-29, 12:27 PM
Of course I don't rule out Jovian-type life, such as those big ol' gasbags & blimps. :D


Somebody on this list recommend a SF book called WHEELERS. It's about the Jovian life--blimps, of course, who live in great floating cities-- and how the Jovians accidentally almost destroy Earth, but before they can correct their error, they have to put the proposal through several committees and debate it for a few thousand years. GREAT BOOK, whoever recommended it!! The Jovian lifeforms are rendered beautifully!

Ilya
2006-Nov-29, 02:07 PM
Only extreme for us, not for extremophiles, if I understand the latest thinking on origins of life (and I'm not an expert). I was referring to the >80C or sub-zero temperatures or ultra acidic/alkiline environments etc that are touted as possible places in the universe that life could have formed.

Saying that since extremophiles on Earth can survive such conditions then it is possible for life to develop in similar conditions elsewhere does not necessarily follow. If the base chemical processes necessary for the creation and development of simple lifeforms cannot exist in those extreme conditions then life cannot evolve in such environments but only adapt to it from elsewhere after evolving more robust chemical reactions.
Possibly. It is also entirely possible that what we consider "benign environment" is actually "extreme" (most likely, too cold) for life to start. The difference between "normal life" and high-temperature extremophiles is that proteins of the latter are wrapped a little tighter. "Normal" proteins unravel at about 60 C; "high-temperature" proteins retain their integrity at 80-120 C, and in fact can not finction effectively at "room temperature" -- it's too cold.

Now, unraveling proteins does not involve breaking molecular bonds -- only the much weaker bonds between molecules (actually, between different parts of one very long molecular chain, in this case). 80 C is not nearly enough to actually disassemble any organic molecules, and 120 C is not that bad either. Hence non-protein chemistry in high-temp extremophiles is pretty much the same as in us -- but all reactions proceed much faster! Pace of chemical reactions roughly doubles with every 10 degrees C. Faster pace is very likely conducive to early life generation. That's basically where the "latest thinking" that life may have originated in ~100 C hydrothermal vents comes from. If true, then we are an extreme-cold adaptation. Notice that the difference between 37 C (us) and -2 C (cold extremophile) is smaller than the difference between 37 C and 100 C (hot extremophile). To a 100 C lifeform, we and what we call "psychrophiles" are equally "psychrophilic".

Ilya
2006-Nov-29, 02:25 PM
Of course I don't rule out Jovian-type life, such as those big ol' gasbags & blimps.

I do. The biggest problem with life on Jupiter (or any gas giant) is that convective currents keep mixing the atmosphere. Any complicated organic molecule will sooner or later (actually, sooner) get dragged into deep layers where it will be destroyed by heat. How do you ever GET to the balloon stage?

greenfeather
2006-Nov-29, 11:58 PM
Maybe they know about us, but don't want to associate with our kind of lowlife!

Oh I firmy believe that the New Horizons team is in for a shock when they photograph Pluto. I think they'll find a gigantic sign stuck in it reading "Danger, Humans next 15 Billion Kilometres. Keep Out!"

Or else the sign will say "Come any closer and we'll show you who's a 'dwarf planet'!!!"

PhantomWolf
2006-Nov-30, 12:38 AM
Or else the sign will say "Come any closer and we'll show you who's a 'dwarf planet'!!!"

Nah, that'll be hastly spray-painted onto the back of it graffetti style. ;)

greenfeather
2006-Nov-30, 01:44 AM
Or else the sign will say "Come any closer and we'll show you who's a 'dwarf planet'!!!"

Nah, that'll be hastly spray-painted onto the back of it graffetti style. ;)

Or else maybe it will say "no lifeforms from big fat overweight giant planets allowed."

loglo
2006-Nov-30, 10:59 AM
...snip..That's basically where the "latest thinking" that life may have originated in ~100 C hydrothermal vents comes from. If true, then we are an extreme-cold adaptation. Notice that the difference between 37 C (us) and -2 C (cold extremophile) is smaller than the difference between 37 C and 100 C (hot extremophile). To a 100 C lifeform, we and what we call "psychrophiles" are equally "psychrophilic".


Thanks Ilya, that is a very interesting point which turns my speculation upside down if the majority of Earth life can be regarded as psychrophilic. :)
This suggests that the conditions required for life to start could be more widespread than I had previously thought.

greenfeather
2006-Nov-30, 10:48 PM
This is a great link--I don't know if I got it from this forum or somewhere else.

http://www.daviddarling.info/encyclopedia/A/ammonialife.html

go backward one level to a whole section on "alternative forms of life". They speculate on life forms based on ammonia, silicon, boron etc. The ammonia life would apparently work in much colder environments than Earth. Like, say, Jupiter.

I printed it out & I'm going to study it along with my 'chemistry for dummies' book!!!

Noclevername
2007-Apr-11, 07:01 AM
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?

It took Earthly life about 3.5 billion years to advance beyond single-celled organisms. The main reason for that appears to be the development of eukaryotic organisms with a more complex and structured cell interior. Given the randomness of mutation, it's concievable that a world's life might not happen to stumble on this precise path of fortunate biology. Thus the cells would remain simple and single, and the path of life on that world would remain at the bacterial level. Nothing is inevitable in evolution.

Noclevername
2007-Apr-11, 07:14 AM
eburacum45 wrote:
But what material goods would be valuable enough to trade over interstellar distances? Any element would be as likely to be found in all the other solar systems, any food or manufactured article would be cheaper to grow or construct at or near the point of construction.

...The procedure for assembly is really all that is required; if each interstellar colony has assembler technology, all that needs to be sent in most cases is the [i]recipe for the item you want- from a glass of orange juice to a spaceship.


Original artwork, celebrities on tour, biomolecules too complex to replicate artificially, tourists, top secret documents which can't be trusted to an open beamcast, holy artifacts for the religious (don't laugh, there are people who literally buy stones "from the cave where Jesus was born"; no, on second thought, laugh like heck).

tdvance
2007-Apr-11, 06:05 PM
I just came across this poll today--and checked "very simple life is common"--but there is some ambiguity (what is "common"?). I think the universe (even the observable portion) is big enough that intelligent life is common, but we could easily be the only ones in the galaxy at this time.

Microscopic life...I'd be surprised if Earth is the only planet in our solar system having that! Scenarios for it existing on Mars, Venus, Europa, IO, and Jupiter have been proposed. Europa is the most likely. So--I suspect very simple life is nearly everywhere. (It's been the dominant form on earth for billions of years).

Finally--no mammals anywhere but earth (unless the universe turns out to be infinite). But something similar to mammals might exist elsewhere--something that gives live birth and provides nourishment somehow while it finishes developing. It could be strange to our minds: mom gives birth and dad gives the "milk" (which may have no resemblance to any earthly milk--could even be the equivalent of the creature's "blood" which might not be red), no self-produced milk but something like what birds do, the creatures could have feathers or other heat-regulating systems instead of fur, four legs might not be standard, breathing and eating might not use the same opening, redundant nerve paths instead of a backbone, and so on.

edit: I see now that it said "organisms as complex as mammals", not 'mammals'.

Noclevername
2007-May-09, 10:36 PM
On earth we colonize where there is reason to colonize, such as trade routes and/or exploitable resources. I would think that aliens would have reason to do the same thing. While we view Earth as special, it may not be such a reasonable place to colonize, due to lack of exploitable resources that can get to market. This is one of the reasons I question the Fermi Paradox.

Historically, a good many of those who led expeditions into unknown lands did so for fame and glory, or for religious reasons, as well as for money. Settlers who colonized these lands were often fleeing persecution or disaster, as well as looking for opportunities, or the freedom of a frontier society-- or to start their own society with their own rules. Not every means of colonization (stretching the definition of the word "colony" there a bit, perhaps settlement or even invasion will do better) is motivated purely by trade. Maybe they might plan to cut off relations with the homeworld and create their own market right here.

(I question the Fermi paradox just 'cause it's not a paradox; the universe is just big, and the neighbors may live far away, that's all. Or right next door and pre-industrial.)