Are we alone? [Archive]

glee

7th May 2004, 08:17 AM

Originally posted by Thomas
Skeptics often use all their talents to debunk UFO sightings, abductions, extraterrestrial material etc., and is quite successful in doing so. I myself has yet to see any conclusive evidence concerning intelligent lifeforms in this universe, but this still doesn't mean that we're alone, or does it?

I don't agree with your characterisation. Skeptics ask to see evidence to back up extraordinary claims. If there is no evidence, they say there is no reason to believe the claim. They stand ready to accept new evidence, and then change their views.

If there is no evidence, then no worthwhile conclusion can be made.
I now tell you that there is a mischievious levitating leprechaun that constantly hovers behind your head. Have you ever seen it? No? Is that a reason not to believe in it?

Originally posted by Thomas
1) Do you belive that we're the only intelligent lifeform in this universe?

1a) If yes: Why?

1b) If no: Why?

/thomas

No, we're probably not alone.
This is based on a mathematical argument.
Life already exists on one planet. There are billions of stars, each of which can have planets. Therefore it is likely that there is life elsewhere in the Universe.
Having said that:

- there is no reason to believe aliens have reached our Solar System
- there is no credible evidence for alien abductions / UFOs / crop circles / life on Mars

Seismosaurus

7th May 2004, 09:09 AM

We know for certain that life is possible, so it's just a matter of whether the universe is a big enough place for it to have developed twice.

Last I heard, the number of stars in the universe was around 10,000,000,000,000,000,000,000. So while the jury is still out, I think it's very close to certain that there is at least one other intelligent life form out there somewhere.

chrisberez

7th May 2004, 09:27 AM

Originally posted by glee

No, we're probably not alone.
This is based on a mathematical argument.
Life already exists on one planet. There are billions of stars, each of which can have planets. Therefore it is likely that there is life elsewhere in the Universe.
Having said that:

- there is no reason to believe aliens have reached our Solar System
- there is no credible evidence for alien abductions / UFOs / crop circles / life on Mars

This is my feeling too. Given the billions of other galaxies out there, there is a strong possibility that there is some form of life out there other than us. This applies as well to the possible existence of intelligent life, although I think the probability drops a little.

I think it's absurd to think aliens have visted our solar system, or even know about it for that matter. Think of how difficult it is for us to detect the existence of other worlds, and even when we manage it, it is impossible to tell if that planet is cabable for supporting life. Thing of how long it would take aliens to get here, even if they did discover us. Think about what would happen to a space ship, if it was able to travel at close-to-light speed, if it encountered even a small cloud of space dust. Judging from how close humans have come (and still come) to destroying themselves the more technology improves. Obviously, that doesn't mean that intelligent life elsewhere would do the same, but given our experience, we have to consider it a factor.

So, Yes, I do think that it is very possible there is intelligent life out there other than us. I do not believe, however, that we will ever contact them, or they us. And I really don't believe for a second that having traversed such a great distance, they would choose to avoid formal contact and instead just analy molest random strangers. That would be like one of us traveling all the way to the Congo by foot just to punch a chimpanzee in the face.

Nyarlathotep

7th May 2004, 10:09 AM

Well, I can't say I know that we are not alone, but if there were some way of knowing for sure, I would be very surprised to find out we were. Space, as Douglas Adams said, is big. With Billions of stars per galaxy and billions of galaxies in the universe, it seems pretty likely to me that life would crop up elsewhere. Just plain odds.

dann

7th May 2004, 10:24 AM

Thomas

7th May 2004, 10:29 AM

Originally posted by glee

I don't agree with your characterisation. Skeptics ask to see evidence to back up extraordinary claims. If there is no evidence, they say there is no reason to believe the claim. They stand ready to accept new evidence, and then change their views.

If there is no evidence, then no worthwhile conclusion can be made.

It wasn't intended as a characterisation, merely a description of what is happening - but I get your point.

I now tell you that there is a mischievious levitating leprechaun that constantly hovers behind your head. Have you ever seen it? No? Is that a reason not to believe in it?

If there were, he's quite quick or not there anymore, because I debunked your proposition with a tennis racket aggressively waved behind my head. I'm damn well not gonna have any levitating leprechauns hovering behind my head without a fight ;)

I know that I have used vague terms for this question, this is why they are formatted with italic and underline. The question might even seem rather stupid. On the other hand, I'm quite new on this forum, and therefore I would like to know what the opinions on this matter is among the skeptics of the world.

/thomas

PS. Dann :D

Hellbound

7th May 2004, 10:50 AM

I think you'll get an abundance of answers here.

The possibilities are really endless. I can offer a few of the theories that are tossed around.

1. We are alone. We are the only intelligent life in the universe.

This is considered in some circles, following various schools of thought:
1a. There is no other life. This may seem unlikely, given the size of the universe, but size does not always mean certanty. One can have an infinite number of oranges with only one apple.
1b. If the age of the Earth is closer to the old estimates, and the age of the universe on the young side, then Earth would be one of the earliest planets formed. We could well have been one of the first types of life to develop. There might be life out there, but it is not yet evolved to the level of intelligence, and might not for some time.
1c. Life is common, but intelligence is a fluke.

2. Life is out there, but it's rare.

Again, a couple versions here I can think of.

2a. Under this idea, life exists, but is so rare/widely scattered that it is no suprise we haven't made contact. We simply are going to need more time, possibly much more time.
2b. Life is out there, but it's afraid. Any technological society will eventually develop the ability to travel (or send objects) at relativistic speeds. Even a relatively small object (space shuttle size) impacting a planet at 50% the speed of light can sterilize a hemisphere (yes, sterilize to the bacterial level). Thus, any technological society is an immediate, imminent threat to other societies in it's galactic neighborhood. Since R-bombs, as they are called, are impossible to stop (never where they are detected at, hard to blow up because then you get shotgunned by debris instead of hit, etc), there is a real risk of genocide. Imagine the cold war, but with unstoppable undetectable nukes. Even MAD fails here. What chance of genocide is acceptable? 10%? 1%? The logical choice is to wipe out any other technological race that approaches this development level. While grim, this theory has been discussed and fits observable data.
2c. Life exists, but is so different from us that it is unrecognizeable. We may have already seens signs of it, but have mistaken it for something else.

3. Life exists, and it's made contact with our government who is dealing with them for technolgoy/survival/to sell people/because they want the secret to infra-black paint.

Just a few theories that I've heard at various locations; figured I'd throw them in to help stir up some discussion. I'm more along the lines of 1b or maybe 2a, but I really can't say yes or no.

rebecca

7th May 2004, 12:42 PM

Originally posted by Thomas
[B]
1) Do you belive that we're the only intelligent lifeform in this universe?

No. Dolphins are pretty intelligent. So are chimps. OH, and I'm pretty sure my cat is a genius.

OK, so that's probably not what you meant. I agree with most of the above. I'm an excellent gambler - I play the odds.

chrisberez

7th May 2004, 12:59 PM

Originally posted by Nyarlathotep
Well, I can't say I know Space, as Douglas Adams said, is big.

...really big! You have no idea how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the street to the chemist's, but that's just PEANUTS to space! Listen..."

Oy. I've read that book and listened to the radio episodes far to many times. Wait. Scratch that. It's not possible to read that book too many time.

Beleth

7th May 2004, 01:05 PM

There is no credible evidence that there is life anywhere but here.

Then again, our whole scientific model is based on the premise that there is nothing at all "special" about where we live. Earth is just a water-covered dust speck in the unfathomably large universe.

Odd are, as someone else said, that we're not the only life in the universe. In fact, I consider discovering that we are the only life in the universe as sufficient proof of Intelligent Design.

Segnosaur

7th May 2004, 01:15 PM

Originally posted by Thomas
1) Do you believe that we're the only intelligent lifeform in this universe?

Given that humans have created reality TV programs, Brittany Spears, disco and the RIAA, I don't even think we can say there's intelligent life down here.

7th May 2004, 01:21 PM

"I think we're alone now
There doesn't seem to be any one around"

Seriously, Thomas, I haven't the foggiest. I have no opinion on this one, I just don't have enough information to start to make a decision.

Nyarlathotep

7th May 2004, 01:26 PM

Here are my two cents (and that's probably about what theya re worth) on the ideas you threw out.
Originally posted by Huntsman

1. We are alone. We are the only intelligent life in the universe.

This is considered in some circles, following various schools of thought:
1a. There is no other life. This may seem unlikely, given the size of the universe, but size does not always mean certanty. One can have an infinite number of oranges with only one apple.
Very true, but very few people are going to say that there is certainly life elsewhere, just that it is exceedingly likely. Simply put if there exists even one apple in with the oranges, that means there exists a way for an apple to get mixed in and, given enough time and enough oranges, there is a pretty good chance that a second apple will crop up sooner or later.

1b. If the age of the Earth is closer to the old estimates, and the age of the universe on the young side, then Earth would be one of the earliest planets formed. We could well have been one of the first types of life to develop. There might be life out there, but it is not yet evolved to the level of intelligence, and might not for some time.

I've never heard this one and I am not all that up on how the age of the earth compares to the rest of the universe. If this is so, it sounds logical enough though.

1c. Life is common, but intelligence is a fluke.
I don't think we have enough information to determine how common or rare intelligence is in the universe. We only have our own planet to compare it to, after all.

2. Life is out there, but it's rare.

Again, a couple versions here I can think of.

2a. Under this idea, life exists, but is so rare/widely scattered that it is no suprise we haven't made contact. We simply are going to need more time, possibly much more time.

This idea seems likely but once again, we don't really have enough data to reach this conclusion. I think if we ever did find conclusive evidence of life on Io or Mars it would tend to work as evidence against this theory. For life to have evolved on two different worlds in our solar system I would think would suggest that life will evolve wherever the conditions are right and there is nothing to suggest that our solar system is so unique to be the only place where such conditions are found.

2b. Life is out there, but it's afraid. Any technological society will eventually develop the ability to travel (or send objects) at relativistic speeds. Even a relatively small object (space shuttle size) impacting a planet at 50% the speed of light can sterilize a hemisphere (yes, sterilize to the bacterial level). Thus, any technological society is an immediate, imminent threat to other societies in it's galactic neighborhood. Since R-bombs, as they are called, are impossible to stop (never where they are detected at, hard to blow up because then you get shotgunned by debris instead of hit, etc), there is a real risk of genocide. Imagine the cold war, but with unstoppable undetectable nukes. Even MAD fails here. What chance of genocide is acceptable? 10%? 1%? The logical choice is to wipe out any other technological race that approaches this development level. While grim, this theory has been discussed and fits observable data.
Unless/until we meet aliens and have some graps of how they think, it seems a bit premature to make guesse as to how they would act in any given situation. Again, we just don't have enough info to suport this conclusion.

2c. Life exists, but is so different from us that it is
unrecognizeable. We may have already seens signs of it, but have mistaken it for something else.
The first part may or may not be true, but I don't see how anyone could conclude that we have already seen it but didn't recognize it. Not based on any data we have that I know of anyway.

3. Life exists, and it's made contact with our government who is dealing with them for technolgoy/survival/to sell people/because they want the secret to infra-black paint.
The holes in that one have been pointed out many,many times.

I think I am with you, though. 1b and 2a seem the most likely to me, but I don't think we really have enough data to back up any conclusion yet

SGT

7th May 2004, 01:45 PM

Life is probably common in the Universe. The abundance and variety of life on Earth in practically any environment, suggests that wherever it is possible, life will emerge.
Inteligence is another problem. We are the effect of several mass extinctions on Earth. The death of the dinossaurs is only the last one. If the dinossaurs were not extinct, the mammals would probably never evolved beyond small, frightened critters.
Could a dinossaur develop inteligence? I don't know.
Mammals, birds, reptiles and fish probably descend from a small, primitive cordate, who lived with large invertebrate predators. The extinction of these predators allowed vertebrates to arouse.
Again, could an invertebrate develop inteligence? I don't know, even if octopusses are pretty smart.

Nyarlathotep

7th May 2004, 01:53 PM

Originally posted by SGT
Life is probably common in the Universe. The abundance and variety of life on Earth in practically any environment, suggests that wherever it is possible, life will emerge.
Inteligence is another problem. We are the effect of several mass extinctions on Earth. The death of the dinossaurs is only the last one. If the dinossaurs were not extinct, the mammals would probably never evolved beyond small, frightened critters.
Could a dinossaur develop inteligence? I don't know.
Mammals, reptiles and fishes probably descend from a small, primitive cordate, who lived with large invertebrate predators. The extinction of these predators allowed vertebrates to arouse.
Again, could an invertebrate develop inteligence? I don't know, even if octopusses are pretty smart.

I am not so sure that the abundance of life on Earth in any way speaks either way to the abundance of life (or lack of it) elsewhere in the universe. Unfortunately, we only have our own Earth as an example and that's just too small of a sample size to draw any conclusions from.

SGT

7th May 2004, 02:27 PM

Originally posted by Nyarlathotep

I am not so sure that the abundance of life on Earth in any way speaks either way to the abundance of life (or lack of it) elsewhere in the universe. Unfortunately, we only have our own Earth as an example and that's just too small of a sample size to draw any conclusions from.

I agree with you, that the sample is small, but life arose pretty soon on Earth (about 1 billion years after the formation). The basic blocks of life, aminoacids, form spontaneously in several environments, so they must exist in other planets.
We limit our discussion to life similar to the one existing on Earth, because we probably could not recognize a very different lifeform.
We need liquid water, a few more or less heavy elements and energy.
As have been pointed, the Universe is so big that it is likely that all of these must exist somewhere. The possibility of life does not mean that life should exist, but if it is possible, there is a probability greater than zero for life. Even a small nonzero probability in a great universe makes the event almost sure.

Nyarlathotep

7th May 2004, 02:44 PM

Originally posted by SGT

I agree with you, that the sample is small, but life arose pretty soon on Earth (about 1 billion years after the formation). The basic blocks of life, aminoacids, form spontaneously in several environments, so they must exist in other planets.
We limit our discussion to life similar to the one existing on Earth, because we probably could not recognize a very different lifeform.
We need liquid water, a few more or less heavy elements and energy.
As have been pointed, the Universe is so big that it is likely that all of these must exist somewhere. The possibility of life does not mean that life should exist, but if it is possible, there is a probability greater than zero for life. Even a small nonzero probability in a great universe makes the event almost sure.

Well, I'll agree that the fact that we even exist shows that intelligent life is possible in the universe (cynical jokes to the contrary aside) and that given the size of the universe the fact that it is possible makes it very likely that it exists on other planets as well.

What I don't know enough to make a decision on, is whether that life is common or not. I don't think we (and I know that I personally) don't have enough information available to us to make more than a wild guess on that subject.

Hellbound

7th May 2004, 02:53 PM

[quote]Unless/until we meet aliens and have some graps of how they think, it seems a bit premature to make guesse as to how they would act in any given situation. Again, we just don't have enough info to suport this conclusion.[quote]

Well, this is based on a three rules, or ideas, that were developed a few years back. Basically, they came up with a list of three rules that one could say about an alien race without knowing anything about them:

Rule 1: They will be intellignet, aggressive, and ruthless when necessary. THis is quite simply because nature doesn't favor a wimp. Natural selection will weed out the weak, and from what we know intelligence arises from predator species. This is partly because the predator has more need for intelligence, but also because large brains, or other organ used for thinking, require a lot of energy..i.e-meat. Basically, bunnies don't get far on the food chain.

Rule 2: They will place the survival of their own species above that of others. We can see this is true with every species on Earth; while it may individually be broken, it remains true in aggregate. Again, this is a simple consequence of evolution. A self-sacrificing species won't survive long. Therefore, when a line is drawn, a species will place it's survival over that of any other species.

Rule 3: They will assume the first two rules apply to us.

But you're right, all of this is pure speculation. But it's fun, ain't it? :D

THis idea, actually, comes from a book called "The Killing Star". (http://www.amazon.com/exec/obidos/tg/detail/-/0380770261/qid=1083963552/sr=1-2/ref=sr_1_2__i2_xgl14/104-3063437-4364701?v=glance&s=books) They reprint email exchanges between NASA and some scientists, and the various future technology in the book is explained in the appendix, with information on current research in these areas and why we think it may or may not be possible. Pretty neat read, and an interesting story :)

Segnosaur

7th May 2004, 03:04 PM

Originally posted by Huntsman

1b. If the age of the Earth is closer to the old estimates, and the age of the universe on the young side, then Earth would be one of the earliest planets formed. We could well have been one of the first types of life to develop. There might be life out there, but it is not yet evolved to the level of intelligence, and might not for some time.

Its been a long time since I studied astronomy so feel free to correct any errors, but I don't think the earth could have been one of the earliest planets formed.

The early universe had only hydrogen and helium... The only way that the heavier elements (such as carbon) could have been formed is through the main sequence of a star (one that eventually went nova). So, earth was formed some time after the first stars and planets came and went, and the remanants of a nova helped form the earth.

I believe the universe has been estimated to be between 10 and 20 billion years old, while the earth is estimated to be about 5 billion.

There is an equation that people use to estimate the number of intelligent species on the planet. I forget the details, but it combines things like: the number of planets in the universe, the chance life exists, the probability that any life will evolve intelligence, etc. Turns out, when you plug all the numbers in, the most important factor is how long an intelligent species survives. Rembember, humans almost ended up having a nuclear war. If an intelligent species can survive a long time, (thousands or millions of years) then there are probably many in the galaxy. But if most intelligent species end up destroying themselves, the number of intelligent species is likely very low.

Hellbound

7th May 2004, 03:10 PM

Seg:

Yes, the Earth would be formed after the first generation of stars, but this is true of any non-hydrogen planet. Let me clarify that the Earth would be one of the earliest terrestrial planets formed.

The universe age, IIRC, is thought to be 13.5 billion years (give or take about 2 billion). The age of the Earth, again IIRC, is thought to be 5 to 8 billion. So, given the time it takes for stars to form, explode, then new stars with planets to form, it is not unreasonable for Earth to be one of the earlier ones. Is it likely? I don't think so. Is it possible? Most definately.

Nyarlathotep

7th May 2004, 03:18 PM

Originally posted by Huntsman

But you're right, all of this is pure speculation. But it's fun, ain't it? :D

Oh, no doubt it's fun. I will have to look for that book, but I don't necessarily agree with the three assumptions though.

Rules 1 & 2 are based on natural selection. I don't think it is too hard to imagine a species advanced enough that natural selection really isn't a factor for them any more. Heck, we are almost there ourselves, since we don't have to worry nearly as much about predators, finding food, and other such agents of natural selection as animals in the wild do. In such a case, that species could easily afford to let its ethics (whatever they may be) have free reign without worrying about natural selection. This would be especially true if that civilization was confident in it's ability to defend itself.

Also, the whole 'R-Bomb" thing makes another big assumption. It assumes that any sufficiently advanced technology will have the means to accelerate things to relativistic speeds. Even if a society possessed technology capable of reaching other stars, this is not necessarily the case. There have been many means (wormholes, folding of space/time,etc) proposed of accomplishing that which do not require the ability to accelerate anything to that kind of speed. Since we have never met a species with this capability, nor do we have it ourselves, we do not know how (or even if) such a feat could be accomplished.

Rule 3 also seems an unwarranted assumption. Again, we have no idea how an alien species might think until we meet one.

Speculation is fun but it works both ways.:)

SGT

7th May 2004, 03:21 PM

Originally posted by Segnosaur

There is an equation that people use to estimate the number of intelligent species on the planet. I forget the details, but it combines things like: the number of planets in the universe, the chance life exists, the probability that any life will evolve intelligence, etc. Turns out, when you plug all the numbers in, the most important factor is how long an intelligent species survives. Rembember, humans almost ended up having a nuclear war. If an intelligent species can survive a long time, (thousands or millions of years) then there are probably many in the galaxy. But if most intelligent species end up destroying themselves, the number of intelligent species is likely very low.

The equation you refer to is the Drake equation , proposed by the astronomer Frank Drake. It involves several parameters whose values we don't know. The site
http://www.station1.net/DouglasJones/drake.htm
presents a calculator and some sensible values to the parameters. Using these values we arrive at 900 technological civilizations in our galaxy, but I have seen another set of parameters whose result is 1. Since we are a technological civilization if this later set is correct, there is no place for another such civilization in our galaxy.

SGT

7th May 2004, 03:39 PM

Originally posted by Huntsman
[quote]Rule 1: They will be intellignet, aggressive, and ruthless when necessary. THis is quite simply because nature doesn't favor a wimp. Natural selection will weed out the weak, and from what we know intelligence arises from predator species. This is partly because the predator has more need for intelligence, but also because large brains, or other organ used for thinking, require a lot of energy..i.e-meat. Basically, bunnies don't get far on the food chain.

Gorillas are fairly intelligent vegetarians.
As for predators developping intelligence I am not so sure. Really fierce predators like the dinossaurs and the sharks have no need of intelligence. Sharks have evolved nothing in 300 million years and they don't need it. They are practically perfect in their environment.
Humans, being somewhat fragile in comparison to other predators and to big preys, had to develop intelligence.

Hellbound

7th May 2004, 03:40 PM

Originally posted by Nyarlathotep
Also, the whole 'R-Bomb" thing makes another big assumption. ... Since we have never met a species with this capability, nor do we have it ourselves, we do not know how (or even if) such a feat could be accomplished.

I have to say nay to this one :)

We already have plans for an anti-matter fueled rocket engine. We produce antimatter in particle accelerators. This could easily get us to these speeds, and is considered highly possible. Fission engines can also get to relativistic speeds. By relativistic speeds that includes anything that's a percentage of the speed of light, starting at 10% and up this can have planet-sterilizing effects (depending on the vessel accelerated...think of a ship that splits into two pieces before impacting a planet, the second piece slowing down to arrive exactly one-half rotation of the planet later. Imagine these two pieces each splitting into several dozen before impact, at a distance calculated to spread the debris field over one planetary diameter...). Anyway, not only is relativistic speed considered possible, it is considered probable. The only reason now for not making an anti-matter engine is the cost of production, but the technology is already here.

The book is a few years old, but they have several copies on Amazon (I ordered one today, I lost my earlier copy :() It is a good read, and the tech they discuss varies from the highly speculative (absorbtion bombs) to the probable (antimatter spacecraft). Anyhow, it's good for ideas :)

I do agree with you that ethics can become major factors in an advanced race, and that's basically the "hole" in the theory. Of course, though, how long it takes these ethics to develop is another argument entirely :)

I did like the concept, though..well, not as an actual possiblity but it is a neat thought experiment. The book includes a central park analogy that's pretty good. All it would take is one xenophobic species to keep an entire galactic area quiet. If they R-bomb other species as soon as they detect a threat, then the only species left would be those that A) kept quiet, reducing all forms of emissions from the planet that could be seen outside the local system (radio, etc), or B) those that R-bombed first.

I agree with you it's unlikely, but again I would not call it impossible.

Correa Neto

7th May 2004, 05:55 PM

I´ll go with the idea that life may be around in other worlds, probably those orbiting Sun-like stars, and perhaps not uncommon. But intelligent life -better yet- complex lifeforms are probably rare. Specially if we take a look of how life evolved here.

If things went a bit different, perhaps there would be nothing but cyanobacteria and jellyfishes around. But again maybe no. Maybe s sentient species could have evolved here millions or hundreds of million years before if things were a bit different.

Anyway, even if our star belongs to the first generation of stars with rocky planets (what is not proved), and assuming we have some sentient neighbors, native to planet around a star with the same age of ours, they are probably from a species hundreds of million years older.

As for their behavior, we have no idea of how such civilization would be. Actually maybe the term "civilization" can not even be used in the case. They may ignore us, if sentient life is common or be very interessed on us, if its rare. Now, xenophobic or conquest-hungry aliens... It seems unlikely to me, but that´s all just guessing.

We also can only glimpse what would such an advanced race use to travel. Maybe even small AI ships, travelling at non-relativistic speeds. Would take time to get the info back? Sure, but what would an alien think of it?

Now, if you excuse me, I have to calibrate the n-space wormhole gravitron beam colimators from that Zeta Reticuli ship. Its creating some chronotron leakage...

Phrost

7th May 2004, 06:13 PM

I find it amusing that anyone could answer anything other than "I don't know".

Unless somehow you have first-hand knowledge one way or another.

Luciana

7th May 2004, 06:22 PM

It's very likely I've picked this argument in an Asimov book, but, if not, you can attribute it to me (less impressive, I know, I know).

No odds can be played. As we speak, we are the ONLY intelligent life known in the universe. Only one. We have not find another to make an estimate, say, 2/1000 are inhabited with intelligent life. It's likely we ARE the only ones to have intelligent life. It is irrelevant how many solar systems there are out there: any estimate by us if flawed, by definition. The ratio could be 2/10^243, for all we know.

I can't say it's likely that there is intelligent life out there. You can't possibly infer that there is, or there is not, with the information currently available.

Ratman_tf

7th May 2004, 07:47 PM

Originally posted by Luciana Nery
It's very likely I've picked this argument in an Asimov book, but, if not, you can attribute it to me (less impressive, I know, I know).

No odds can be played. As we speak, we are the ONLY intelligent life known in the universe. Only one. We have not find another to make an estimate, say, 2/1000 are inhabited with intelligent life. It's likely we ARE the only ones to have intelligent life. It is irrelevant how many solar systems there are out there: any estimate by us if flawed, by definition. The ratio could be 2/10^243, for all we know.

I can't say it's likely that there is intelligent life out there. You can't possibly infer that there is, or there is not, with the information currently available.

Yep.
We have yet to survey all the planets in OUR solar system (but the chances on intelligent life in our solar system are pretty slim at this point) much less planets outside it. We just don't have enough info to even make a potshot at a guess at this point.

Fun to speculate though. :D

Explorer

8th May 2004, 05:12 AM

test

Bottle or the Gun

8th May 2004, 05:27 AM

Here's the formula for calculating the possibility of other civilizations.
Drake's Equation (http://www.planetarysystems.org/drake_equation.html)

Also, as far as other intelligent life in the universe, Sagan once said that somebody had to be the first (or the last), and it could be us.

Yahweh

8th May 2004, 12:23 PM

At the moment, we are aware there is a 100% chance of intelligent life developing in the universe, as well a 100% chance of unintelligent life developing in the universe under extreme conditions.

Besides, why would God create this huge huge huge universe and only put one hospitible planet in it?

MLynn

8th May 2004, 01:08 PM

I don't know. I think it's interesting that so far we can't even figure out if there is/was any life on Mars.

Whenever I take a look at the National Geographic map of the known universe, the Earth looks awfully puny.

billydkid

8th May 2004, 01:33 PM

It is unreasonble to the point of being idiotic to suppose that in this incomprehensibly vast universe our little planet is the only place where life has managed to seed itself and thrive. In fact, I would have to say it would not be rational to argue that there are not likely hundreds of millions of planets harboring life of one sort or another.

DangerousBeliefs

8th May 2004, 03:34 PM

We are a sample size of 1, unfortunately.

So, its hard to draw any conclusions.

If I were to guess, I'd say the universe is teaming with life.

thaiboxerken

8th May 2004, 04:47 PM

Of course there are other intelligent beings out there, don't you watch Star Trek?!

Batman Jr.

8th May 2004, 08:16 PM

Originally posted by Ratman_tf

Yep.
We have yet to survey all the planets in OUR solar system (but the chances on intelligent life in our solar system are pretty slim at this point) much less planets outside it. We just don't have enough info to even make a potshot at a guess at this point.

Fun to speculate though.

Once we become capable of emulating the processes which gave rise to life here on Earth, and perhaps even those which we would presume to have given rise to life on other planets, it will actually be quite possible for us to assess our chances of being alone in the universe without having to traverse large distances across our vast cosmos. Am I incorrect in this reasoning?

Oso

8th May 2004, 08:51 PM

Originally posted by Thomas
...
Do you believe that we're the only intelligent lifeform in this universe?
...First we need to establish an unambiguous definition of intelligence. The ability to build a microwave oven, should do just fine.

Next it seems we have to narrow the scope to concurrent intelligent lifeforms. Even assuming we stick around for tens of millions of years that's a match strike to the age of the universe, and the other lifeform(s) has to fall in this same brief flash. Plus or minus a comet or two our period of existence could have come hundreds of millions of years before or after, even assuming intelligence is inevitable.

So for any chance of concurrent intelligence at least one of us has to stay viable for tens of millions of years. What're the odds? Oh yeah that was the original question. My guess is we'll never know, but I still voted no.

edited to correct my vote indication. I meant 'yes' there is intelligent life.

glee

9th May 2004, 08:27 AM

Originally posted by Thomas
It wasn't intended as a characterisation, merely a description of what is happening - but I get your point.

If there were, he's quite quick or not there anymore, because I debunked your proposition with a tennis racket aggressively waved behind my head. I'm damn well not gonna have any levitating leprechauns hovering behind my head without a fight ;)

I know that I have used vague terms for this question, this is why they are formatted with italic and underline. The question might even seem rather stupid. On the other hand, I'm quite new on this forum, and therefore I would like to know what the opinions on this matter is among the skeptics of the world.

/thomas

I think saying 'Skeptics often use all their talents to debunk UFO sightings, abductions...' is inaccurate and slightly offensive.

My example of the leprechaun should have included that he has ESP, so can easily dodge your racquet ;) .

Of course you don't believe in the leprechaun. But this idea came from your phrase 'I myself has yet to see any conclusive evidence concerning intelligent lifeforms in this universe, but this still doesn't mean that we're alone, or does it?'.
Hopefully you wouldn't say 'I myself has yet to see any conclusive evidence concerning levitating leprechauns, but this still doesn't mean that they don't exist, or does it?'

Evidence is what matters. You have no reason to believe in leprechauns, but there is evidence of life on one planet. However, as others have said, a sample size of one does not permit any accurate deduction.

glee

9th May 2004, 08:32 AM

Originally posted by Beleth
There is no credible evidence that there is life anywhere but here.

Then again, our whole scientific model is based on the premise that there is nothing at all "special" about where we live. Earth is just a water-covered dust speck in the unfathomably large universe.

Odd are, as someone else said, that we're not the only life in the universe. In fact, I consider discovering that we are the only life in the universe as sufficient proof of Intelligent Design.

Why is there not something special about our planet / solar system? I don't mean religious mumbo-jumbo, just that there may be a combination of circumstances (planetary satellite / type of star / local resources) that caused life in this particular place.

If we are the only life in the Universe, then by definition God doesn't exist.

glee

9th May 2004, 08:35 AM

Originally posted by SGT
The equation you refer to is the Drake equation , proposed by the astronomer Frank Drake. It involves several parameters whose values we don't know. The site
http://www.station1.net/DouglasJones/drake.htm
presents a calculator and some sensible values to the parameters. Using these values we arrive at 900 technological civilizations in our galaxy, but I have seen another set of parameters whose result is 1. Since we are a technological civilization if this later set is correct, there is no place for another such civilization in our galaxy.

Thanks for the reference.
However statistically a result of 1 technological civilization just means it is likely there is only 1, not a guarantee.

glee

9th May 2004, 08:41 AM

Originally posted by Yahweh
Besides, why would God create this huge huge huge universe and only put one hospitible planet in it?

1. God died before he could finish another lifeform.
2. God got bored with creating.
3. God is away on holiday.
4. God decided to have just one lifeform in this Universe (he has lots of other Universes)
5. God retired.
6. God likes us to have plenty of room.

I could go on, but that's enough examples of religion meeting science (unless you can tell me how many angels can dance on the head of a pin?)

glee

9th May 2004, 08:44 AM

Originally posted by billydkid
It is unreasonble to the point of being idiotic to suppose that in this incomprehensibly vast universe our little planet is the only place where life has managed to seed itself and thrive. In fact, I would have to say it would not be rational to argue that there are not likely hundreds of millions of planets harboring life of one sort or another.

Um, you really need to learn the difference between 'mathematical likelihood', 'deduction', 'idiotic' and 'irrational'*.

Unless this* was a deliberate pun?

Pantastic

9th May 2004, 08:47 AM

Lots of people are making a classic error in stating that because the universe is SO vast and there are SO MANY stars, that there MUST be life out there somewhere. Unfortunately, this arguement is based on probability when you don't actually know what the probability of life developing is.

One post states the number of stars at 10^22 or similar, so there must be at least one with life, right? Well, what if the chance of life developing on a planet is 1 in 10^10000? In that case, its extremely unlikely that there is life out there. On the other hand, maybe the chance is 1 in 100.

NO ONE KNOWS.

With only one planet we know of harbouring life (Earth), there is no way to extrapolate from that the chance of other planets having life. Perhaps, even given the incomprehensible number of stars in the universe, the chances of life developing are so slim, that you would still bet against it happening.

glee

9th May 2004, 08:49 AM

Originally posted by Oso
First we need to establish an unambiguous definition of intelligence. The ability to build a microwave oven, should do just fine.

Presumably you refer to some sort of 'species intelligence', since I doubt many people could build a microwave oven.
It also means you don't believe dolphins are intelligent (and no aquatic lifeform can ever be.)

Is a termite hill evidence of intelligence? it seems pretty impressive for countless small insects to build such a well-designed structure without blueprints or education.

glee

9th May 2004, 08:54 AM

Originally posted by Pantastic
Lots of people are making a classic error in stating that because the universe is SO vast and there are SO MANY stars, that there MUST be life out there somewhere.

I hope you're not including me in this. I said (added bolding for emphasis):

No, we're probably not alone.
This is based on a mathematical argument.
Life already exists on one planet. There are billions of stars, each of which can have planets. Therefore it is likely that there is life elsewhere in the Universe.

Just for interest, do you want to list the posters who stated there must be life somewhere?

billydkid

9th May 2004, 09:18 AM

Originally posted by Pantastic
Lots of people are making a classic error in stating that because the universe is SO vast and there are SO MANY stars, that there MUST be life out there somewhere. Unfortunately, this arguement is based on probability when you don't actually know what the probability of life developing is.

One post states the number of stars at 10^22 or similar, so there must be at least one with life, right? Well, what if the chance of life developing on a planet is 1 in 10^10000? In that case, its extremely unlikely that there is life out there. On the other hand, maybe the chance is 1 in 100.

NO ONE KNOWS.

With only one planet we know of harbouring life (Earth), there is no way to extrapolate from that the chance of other planets having life. Perhaps, even given the incomprehensible number of stars in the universe, the chances of life developing are so slim, that you would still bet against it happening.

No, it is not a matter of the probability that life would develop. It is the mathematical likelyhood that this planet is unique among all of the thousands of billions of other celestial bodies in the universe in its having had the capacity to spawn life. One must concede that it is extremely unlikely that there have not existed many billions of planets on which conditions have existed which could have produced life. Amound all of those it is further extremely unlikely that only our earth succeeded in doing so. You don't have to do the calculations to recognize this.

In the same way that, given a vast expanse of time and the nature of life on earth, a process of evolution is not merely likely, it is inevitable and unavoidable and to deny it is to be willfully stupid - the process of the generation of life given almost infinite opportunity simply has to happen. It would take some sort of supernatural intervention to stop it from occurring and to suppose that it hasn't happened many times all over the place is akin to believing in the the supernatural.

Pantastic

9th May 2004, 09:18 AM

Okay, okay. No one actually used the term 'must', perhaps that was not the right word. But plenty of 'it is likely', 'I'd bet on it' and so on (including billydkid's thoughts that it is irrational not to think there is life all over the universe), based on the idea that there are so many stars.

Saying 'it is likely' is still based on a flawed premise - that the number of planets needed to make it likely that life would develop on one of them is less than the number of planets in the universe. How can you say this?

I didn't mean to pick on any poster in particular, but simply to point out that I think the mathmatical argument based on the number of stars/planets is flawed. It's something I used to subscribe to, but I realised my mistake when I read a section in one of Richard Dawkins' books (Blind Watchmaker I think it was), on the chances of life on other planets.

Pantastic

9th May 2004, 09:26 AM

Originally posted by billydkid

No, it is not a matter of the probability that life would develop. It is the mathematical likelyhood that this planet is unique among all of the thousands of billions of other celestial bodies in the universe in its having had the capacity to spawn life. One must concede that it is extremely unlikely that there have not existed many billions of planets on which conditions have existed which could have produced life. Amound all of those it is further extremely unlikely that only our earth succeeded in doing so. You don't have to do the calculations to recognize this.

In the same way that, given a vast expanse of time and the nature of life on earth, a process of evolution is not merely likely, it is inevitable and unavoidable and to deny it is to be willfully stupid - the process of the generation of life given almost infinite opportunity simply has to happen. It would take some sort of supernatural intervention to stop it from occurring and to suppose that it hasn't happened many times all over the place is akin to believing in the the supernatural.

I disagree. Why are these things 'extremely unlikely'?

As far as I am aware, a mathmatical likelihood IS a probability. In the same way as you can't decide if a medical treatment works or not from a single case (homeopathy aside );), you can't decide if life on Earth was inevitable given our distance from the sun and so on, or whether it was a fluke so astronomical that the chances of it having happened anywhere else in the universe are slim to none. With only one case, statistics are meaningless.

billydkid

9th May 2004, 09:33 AM

Originally posted by glee

I hope you're not including me in this. I said (added bolding for emphasis):

No, we're probably not alone.
This is based on a mathematical argument.
Life already exists on one planet. There are billions of stars, each of which can have planets. Therefore it is likely that there is life elsewhere in the Universe.

Just for interest, do you want to list the posters who stated there must be life somewhere?

Fine, I stated it. Obviously it isn't necessarily true that there "must" be life on other planets, but to suppose there isn't is to be willfully contrary. I see no difference between the position that we "don't know" whether or not there is life on other planets and the position that we don't know whether or not there is life after death. Both positions promote the notion that this or that might be true however utterly unlikely. Tough way to go through life, being open to the possibility that every single undisprovable proposition, however absurd "just might be true". At a certain point common sense has to trump ridiculousness. And, yes, I would hold that it is ridiculous to suppose that the earth is unique in the universe in it capacity to have produced life.

SGT

9th May 2004, 10:30 AM

Originally posted by glee

Why is there not something special about our planet / solar system? I don't mean religious mumbo-jumbo, just that there may be a combination of circumstances (planetary satellite / type of star / local resources) that caused life in this particular place.

If we are the only life in the Universe, then by definition God doesn't exist.

Of course God exists. He/She created us and verified it was a big mistake. So, He/She sent a universal flood and obliterated almost all of the creation. After this failure He/She decided that all those other planets he created to harbor life should be barren.
That is the reason why Earth is the sole planet to harbour inteligent life os perhaps life of any kind.

glee

9th May 2004, 02:40 PM

Originally posted by Pantastic
Okay, okay. No one actually used the term 'must', perhaps that was not the right word. But plenty of 'it is likely', 'I'd bet on it' and so on (including billydkid's thoughts that it is irrational not to think there is life all over the universe), based on the idea that there are so many stars.

Saying 'it is likely' is still based on a flawed premise - that the number of planets needed to make it likely that life would develop on one of them is less than the number of planets in the universe. How can you say this?

I didn't mean to pick on any poster in particular, but simply to point out that I think the mathmatical argument based on the number of stars/planets is flawed. It's something I used to subscribe to, but I realised my mistake when I read a section in one of Richard Dawkins' books (Blind Watchmaker I think it was), on the chances of life on other planets.

Well it's a discussion board so you must try to be as precise in your posting as possible - we can't see your facial + other gestures!

It's not a flawed premise to say that because there are a lot of planets, then life is likely.
If we only observed a handful of planets in the known Universe, then the existence of other lifeforms would be far less likely.

Basically we don't have enough information, such as the chance of life on a single planet.