Are we alone?

[sman]

This was the caption a couple of months ago on the cover of a popular magazine we subscribe to . The article was about exoplanets. It seemed completely inappropriate to me. The fact that we can detect (Jupiter-like) planets in orbit around other stars I find fascinating and exciting, but the idea doesn’t immediately lead me to think that there might be someone on one of them that I might talk to.

 

I think it is an unfounded fantasy. There it is. I think the likelyhood of humans encountering extra-terrestrial intelligence is beyond what we should reasonably think of as possible. Like the likelyhood of me suddenly levitating in thin air here as I type, or of all the molecules in my body suddenly, simultaneously wandering off in separate directions.

 

It is a tantalizing idea to many, many people that intelligence may have emerged somewhere else in the nearby cosmos & that we may be able to communicate. Just the fact that popular magazines will use it to sell a loosely related article should alert us that it is tempting to think - and we should be extra-cautious. Everybody wants there to be aliens that we can talk to. It reminds me of the God hypothesis. Everybody wants there to be a God and does everything they can to justify the thinking.

 

Both are terrifying to me. And I find both equally untenable. (Thank God!)

[Moontanman]

I'm not sure how untenable this is, a large exoplanet could very well have habitable moons, and we have found Earth class planets as well.

 

The idea that aliens would be god like is, I think, making some quite large assumptions. It depends a lot on how much we really know about the cosmos and laws that regulate it. If, indeed, we know as much as we think then aliens are pretty much confined to their own solar systems or at most a very slow march across the galaxy and planets like the Earth would probably be avoided in favor of hotter stars with more debris around them due to any slow moving generation type ships would be the homes of the aliens and planets and gravity wells would probably be avoided.

 

I doubt aliens would be interested in the earth for many reasons (other than maybe just scientific curiosity) There is no reason to think that alien life would be compatible with earth life, even if they use the same nucleotides in they use for DNA the proteins and such would probably be incompatible, even things like trace elements could be totally different Arsenic could replace phosphorus like it already does in some Earthly life forms. A planet could easily have different concentrations of various trace elements and they would be totally incompatible with Earth life forms due to it.

 

Are Aliens Among Us?: Scientific American Slideshows

 

Researchers have hypothesized that in alien organisms arsenic could successfully fill the biochemical role that phosphorus plays for known life-forms. Arsenic is poisonous to us because it mimics phosphorus so well; similarly, phosphorus would be poisonous to an arsenic-based organism.

 

Different concentrations of heavy metals would make the Earth incompatible with life from another planet, mercury could easily be far to common in the biochemistry of another planet for instance.

 

another thing to keep in mind is how common life is or in this case intelligent life. If for instance there were several thousand civilization in our Galaxy they would still average thousands of light years apart. Since communication is limited to light speed no civilization would be aware of us for many hundreds if not thousands of years.

 

On top of that is the fact that the ability of the Earth or a similar planet to be detected over many light years is greatly exaggerated. If the earth wanted to be detected we could send a signal that could eventually be detected billions of light years away. But the common leakage of normal radio and other electromagnetic signals could not be detected by another world of equal technology even a couple light years away.

 

Interstellar dust and natural signals swamp any leaked earth signals way before they would even reach the nearest stars. If an earth technology planet was orbiting around alpha centari we would be hard pressed to detect them unless they were intentionally signaling.

 

The lack of detection of aliens could indeed be simply because they are not interested in being found and a super civilization would probably leak even less in the way of signals due to more efficient com type systems to stop wasted energy.

 

It is even possible that aliens are already in our solar system harvesting resources from kuiper belt objects and even closer asteroids, hiding from us would not be difficult and if they had been here for a long time they would have had a long time to decide on whether to stay hidden or not and adapted their technology to suit. Such a civilization having no need for planets could indeed already occupy most of the galaxy and we would be totally unaware of them.

[Turtle]

This was the caption a couple of months ago on the cover of a popular magazine we subscribe to . The article was about exoplanets. It seemed completely inappropriate to me. The fact that we can detect (Jupiter-like) planets in orbit around other stars I find fascinating and exciting, but the idea doesn’t immediately lead me to think that there might be someone on one of them that I might talk to.

 

I think it is an unfounded fantasy. There it is. I think the likelyhood of humans encountering extra-terrestrial intelligence is beyond what we should reasonably think of as possible. Like the likelyhood of me suddenly levitating in thin air here as I type, or of all the molecules in my body suddenly, simultaneously wandering off in separate directions.

 

 

possible - definition of possible by the Free Online Dictionary, Thesaurus and Encyclopedia.

1. Capable of happening, existing, or being true without contradicting proven facts, laws, or circumstances

...

4. Of uncertain likelihood.

 

so, on definition 1., the exo-planet-with-life does not violate any circumstances of life as we know it, in fact it is because they do have similar circumstances/conditions to our planet that the idea comes up. :phones: on #4, the best anyone has put forward on the certainty of life elsewhere is the drake equation, and it is certainly uncertain so, we don't know with any certainty how likely life is to arise outworld of us.

 

the other definitions @ the link may or may not apply, but you can check them there.

 

just started wondering what the likelihood, say probability, is of a meteor vaporizing a person? i think that would satisfy the "all the molecules in my body suddenly, simultaneously wandering off in separate directions." query. :cheer: :rolleyes:

 

now chore to your everyday returns and stop interupting our study. we are from France.

[Moontanman]

Being hit by a meteor is very a low but not non zero possibility, there has been some property damage by meteors in recent times, very recently a doctors office was damaged by a meteorite. a woman was hit while lay in bed a few decades ago but she was not killed, just bruised badly. now actually being vaporized is a different thing, it would take a quite large meteorite to do that. I'm not sure how large but I would think a few tons at least.

[Turtle]

Being hit by a meteor is very a low but not non zero possibility, there has been some property damage by meteors in recent times, very recently a doctors office was damaged by a meteorite. a woman was hit while lay in bed a few decades ago but she was not killed, just bruised badly. now actually being vaporized is a different thing, it would take a quite large meteorite to do that. I'm not sure how large but I would think a few tons at least.

 

roger. so, the probability of a 3 ton meteor entering under any circumstance is part of the calculation. person or no, we know this has happened, and that is my point. it isn't simply "non-zero", which used as you have implies "so unlikely as to be virtually impossible", which is what sman is saying, which is what i don't agree with. got all that? :phones:

 

here we are on this rock, evolved from gook and when we got up out of the gook we look out at other rocks & see they have similar gook and it is not any sort of wild stretch of the imagination to ask the question "are we alone?" any more than when we looked out at the horizon and asked "is this rock round?".

:rolleyes:

/forums/images/smilies/banana_sign.gif

[Moontanman]

roger. so, the probability of a 3 ton meteor entering under any circumstance is part of the calculation. person or no, we know this has happened, and that is my point. it isn't simply "non-zero", which used as you have implies "so unlikely as to be virtually impossible", which is what sman is saying, which is what i don't agree with. got all that? :phones:

 

here we are on this rock, evolved from gook and when we got up out of the gook we look out at other rocks & see they have similar gook and it is not any sort of wild stretch of the imagination to ask the question "are we alone?" any more than when we looked out at the horizon and asked "is this rock round?".

:rolleyes:

/forums/images/smilies/banana_sign.gif

 

 

I would say the probability of life, even complex life, being with in say 100 light years of the earth is many many times higher than you being vaporized by a meteorite. I would be willing to say it's almost a sure thing compared to being vaporized by a meteorite. A Tunguska type event Tunguska event - Wikipedia, the free encyclopedia is far more likely to get you and a lot of other people at once than you are to be individually killed.

[Turtle]

I would say the probability of life, even complex life, being with in say 100 light years of the earth is many many times higher than you being vaporized by a meteorite. I would be willing to say it's almost a sure thing compared to being vaporized by a meteorite. A Tunguska type event Tunguska event - Wikipedia, the free encyclopedia is far more likely to get you and a lot of other people at once than you are to be individually killed.

 

well, let's see some calculations to support that. :rolleyes: it's not enough to just throw out what you "believe" or "think" or "would say" if you connect that to a likelihood or probability and then not show some actual probablities, formulae, data, or supporting material. my point, again, is that i assert that sman's assertion that asking "are we alone?" is a query of "unfounded fantasy" is mistaken. since i know from previous conversations that you agree with this, i fail to see why you want to dance with me over it. we have trolls here for that kind of thing ya know. :phones:

[Moontanman]

Turtle you made the assertion about the meteorite not me, I simply said the possibility of being killed by a meteorite is quite small, if it were not it would happen regularly with 6 billion of more targets on the earth and no recorded incidence of death by meteorite i would say it's quite improbable, especially when you consider that huge explosions of meteorites occur on the average of every 24 hours in the Earth's upper atmosphere. (see the Tunguska link for how often and how big) If it was likely it would happen regularly. Actually the main reason it doesn't happen regularly is the Earths atmosphere, meteors above a certain size generally explode, below that they burn up, very few large chunks ever really hit the Earth, the ones that do are traveling slowly due to the Earths atmosphere slowing them down, like a human falling from 30,000 feet or 10,000 feet they both hit at the same speed.

 

As for "are we alone", I would say absolutely not, the question is not are we alone but how far away are they.

[Moontanman]

Turtle you made the assertion about the meteorite not me, I simply said the possibility of being killed by a meteorite is quite small, if it were not it would happen regularly with 6 billion of more targets on the earth and no recorded incidence of death by meteorite i would say it's quite improbable, especially when you consider that huge explosions of meteorites occur on the average of every 24 hours in the Earth's upper atmosphere. (see the Tunguska link for how often and how big) If it was likely it would happen regularly.

Death by meteorite | Bad Astronomy | Discover Magazine

As for "are we alone", I would say absolutely not, the question is not are we alone but how far away are they.

[Turtle]

Turtle you made the assertion about the meteorite not me, ...

 

correct; you're just the one that took it out of the context i gave it in. it's for sman. ;)

 

 

 

...I simply said the possibility of being killed by a meteorite is quite small,

i simply said, tell me how small. like in probability of .000045 or such a matter & say how you got it.

 

...if it were not it would happen regularly with 6 billion of more targets on the earth and no recorded incidence of death by meteorite i would say it's quite improbable, especially when you consider that huge explosions of meteorites occur on the average of every 24 hours in the Earth's upper atmosphere. (see the Tunguska link for how often and how big) If it was likely it would happen regularly.

Death by meteorite | Bad Astronomy | Discover Magazine

 

well, apparently you missed this then: >> Mammoth Comet Extinction...

 

As for "are we alone", I would say absolutely not, the question is not are we alone but how far away are they.

 

i believe i said that. :Alien:

[Moontanman]

correct; you're just the one that took it out of the context i gave it in. it's for sman. ;)

 

I think you're just being difficult, where is that little park you are so enamored with? I think I'll hunt you down , tie you up and turn a Beaver loose on you, but you'd probably enjoy it :evil:

 

i simply said, tell me how small. like in probability of .000045 or such a matter & say how you got it.

 

1/700,000 to being killed along with many others, I cannot find serious figures on you personally alone in your little park being killed, I suspect it's far to low to be expressed meaningfully.

 

 

well, apparently you missed this then: >> Mammoth Comet Extinction...

 

Nope, it simply wasn't relevant to your question of personally being killed.

 

i believe i said that. :Alien:

 

I believe I said it first, now I'm wishing for that meteorite :Alien:

 

Absence of evidence is not evidence of absence ;)

[sman]

I see I've caught a couple of believers in my net. No need to be gentle. The "Contact" fantasy is something you both hold dear - and I've compared it with the God delusion. I expected to be attacked. :Alien:

 

I'm not sure how untenable this is, a large exoplanet could very well have habitable moons, and we have found Earth class planets as well. - Moontanman

 

Don't get me wrong. The main reason I get excited when I hear these kinds of things - earth class planets of other solar systems - is the possibility of extra-terrestrial life. But intelligent life is a different matter.

 

Bacterial life emerged here on earth just about as soon as the conditions allowed for it. I wouldn't be surprised if it turned out to be common. But to discover something analogous of bacteria on another world would not address our sensibilities - the question "are we alone?" does not have bacteria in mind, does it.

 

The fantasy is that there is another planet out there in the cosmos housing beings that we may exchange information and technology and philosophy with.

 

well, let's see some calculations to support that. ;) it's not enough to just throw out what you "believe" or "think" or "would say" if you connect that to a likelihood or probability and then not show some actual probablities, formulae, data, or supporting material. :Alien: my point, again, is that i assert that sman's assertion that asking "are we alone?" is a query of "unfounded fantasy" is mistaken.

 

I am certainly not the one to do the math. But I have some idea of the math that you are asking for. Here you may sneer at my child-like understanding of probability, but please correct me if I steer it wrong.

 

My definition of impossibility is statistical. If I roll a single die, the possibility of rolling a 6 is one in 6 so, on average, I should have to roll six times to get a 6. If I have a 100million-sided die (that somehow fits in the palm of my hand) I should need a hundred million rolls - a generational commitment. But we could speed up the experiment by recruiting other die-rollers. If we had 100 million smans, each equipped with crap table & super-die, me & my army of idiots should produce a six on the first roll. (on average)

 

Now, even I can tell that there is a limit to these numbers. There are only so many particles available in the universe for dice, and there is only so much time in the universe for die-rolls. This can be trimmed back quite a bit. We will never have access to the whole universe - so all we have to consider is the number of particles in our immediate vicinity, say, 100 light years out, as moonman suggest - that's not unreasonable. And we don't have the entire age of the universe to play with either. We are looking for beings that have evolved on 2nd or 3rd generation stars, with heavy, complicated elements in their systems. It takes awile for a star to die a couple of times.

 

Drake Equation, thank you.

 

The Drake equation states that:

 

 

where:

 

N = the number of civilizations in our galaxy with which communication might be possible;

and

 

R* = the average rate of star formation per year in our galaxy

fp = the fraction of those stars that have planets

ne = the average number of planets that can potentially support life per star that has planets

fℓ = the fraction of the above that actually go on to develop life at some point

fi = the fraction of the above that actually go on to develop intelligent life

fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

L = the length of time such civilizations release detectable signals into space.[2]

 

The problem I have with the Drake equation is that it's hard to tell how many dice we need to roll. Intelligent life may seem like one die roll away from life, but I think it is many:

 

Not every species in an eco-system is eligible for intelligence. Most are prey, and we need predators, or at least omnivors, like us.

 

The fraction of (non-prey) species that develop stereoscopic tri-color(or tetra-color) vision. This is more important than you might think. Look into the fabulous circumstances that led to this development in humans.

 

The fraction of the above that are organized into social groups.

 

The fraction of the above that, by some means, can pool their experiences and accumulate knowledge extra-genetically.

 

...the list goes on. None of these things are commonplace on earth - a planet teeming with diversity.

 

I'd say we need to come "down to earth" about this, but that lands us in the sampling error that riddles this proplem: We only know of one sample, earth. :evil:

[Moontanman]

I see I've caught a couple of believers in my net. No need to be gentle. The "Contact" fantasy is something you both hold dear - and I've compared it with the God delusion. I expected to be attacked. ;)

 

No attack, just a more reasonable take on the data.

 

Don't get me wrong. The main reason I get excited when I hear these kinds of things - earth class planets of other solar systems - is the possibility of extra-terrestrial life. But intelligent life is a different matter.

 

Yes, you got that correct.

 

Bacterial life emerged here on earth just about as soon as the conditions allowed for it. I wouldn't be surprised if it turned out to be common. But to discover something analogous of bacteria on another world would not address our sensibilities - the question "are we alone?" does not have bacteria in mind, does it.

 

No it does not, would you accept complex life or do you insist on a radio telescope building aliens?

 

The fantasy is that there is another planet out there in the cosmos housing beings that we may exchange information and technology and philosophy with.

 

I see so you do need electronic technology at least.

 

 

I am certainly not the one to do the math. But I have some idea of the math that you are asking for. Here you may sneer at my child-like understanding of probability, but please correct me if I steer it wrong.

 

My definition of impossibility is statistical. If I roll a single die, the possibility of rolling a 6 is one in 6 so, on average, I should have to roll six times to get a 6. If I have a 100million-sided die (that somehow fits in the palm of my hand) I should need a hundred million rolls - a generational commitment. But we could speed up the experiment by recruiting other die-rollers. If we had 100 million smans, each equipped with crap table & super-die, me & my army of idiots should produce a six on the first roll. (on average)

 

Now, even I can tell that there is a limit to these numbers. There are only so many particles available in the universe for dice, and there is only so much time in the universe for die-rolls. This can be trimmed back quite a bit. We will never have access to the whole universe - so all we have to consider is the number of particles in our immediate vicinity, say, 100 light years out, as moonman suggest - that's not unreasonable. And we don't have the entire age of the universe to play with either. We are looking for beings that have evolved on 2nd or 3rd generation stars, with heavy, complicated elements in their systems. It takes awile for a star to die a couple of times.

 

Drake Equation, thank you.

 

You are wrong and I think Drake is misleading, the Drake equation has far to many of it's variables as unknowns. Until we get more of the unknowns better understood it's not much better than my guesses and assumptions.

 

 

The problem I have with the Drake equation is that it's hard to tell how many dice we need to roll. Intelligent life may seem like one die roll away from life, but I think it is many:

 

Not every species in an eco-system is eligible for intelligence. Most are prey, and we need predators, or at least omnivors, like us.

 

The fraction of (non-prey) species that develop stereoscopic tri-color(or tetra-color) vision. This is more important than you might think. Look into the fabulous circumstances that led to this development in humans.

 

The fraction of the above that are organized into social groups.

 

The fraction of the above that, by some means, can pool their experiences and accumulate knowledge extra-genetically.

 

...the list goes on. None of these things are commonplace on earth - a planet teeming with diversity.

 

I'd say we need to come "down to earth" about this, but that lands us in the sampling error that riddles this proplem: We only know of one sample, earth. :Alien:

 

You are correct, we simply do not know enough to really guess much less use equations at this point,

 

My guess is that you have been reading "Rare Earth" by Ward and Brownlee

 

Rare Earth hypothesis - Wikipedia, the free encyclopedia

 

Some of their assumptions have been shown to be, if not wrong, at least unreasonable. I expect complex life to be reasonably common in our galaxy, bacterial type life to be common as asses on humans. But as you pointed out the real $64,000 question is intelligent technological life. There is no way to really say how common, anything anyone comes up with is no better than a guess.

 

There is some reason to be skeptical of intelligent life, we can postulate that our own civilization is capable with only slightly more advanced technology than we now have to occupy the entire galaxy in less than one million years. self sustaining freely moving colony type ships or artificial worlds could spread through out the galaxy quite quickly in terms of geologic time. such aliens would not need and probably avoid large planets and as I said in my first post they could be actively harvesting the resources of our own solar system with out our knowledge.

 

So we are faced with the possibility that we are alone, we are not alone but no one has been around long enough to really do anything or They are pretty much where ever they want to be and are ignoring us. :Alien:

[Turtle]

I think you're just being difficult, where is that little park you are so enamored with? I think I'll hunt you down , tie you up and turn a Beaver loose on you, but you'd probably enjoy it :Alien:

 

:Alien: get in line son. 45º 38' 50" N 122º 27' 37.35" W

 

I'd say we need to come "down to earth" about this, but that lands us in the sampling error that riddles this proplem: We only know of one sample, earth.

 

ok. but since you said this is "unfounded fantasy" to ask about intelligent life off-world, then that would make this a thread for Silly Claims and not Space. :evil: i don't "believe" anything about the answer to the question, rather i believe only that the question be reasonable & reasonably put. ;)

 

aside:

Why People Probably Don't Understand Probability

...

Professor GELMAN: As a way of giving students an intuition into randomness, we divide the class and then I leave the room. One half of the class has to create a sequence of 100 coin flips, and then they're told to write it on the blackboard as a sequence of zeros and ones.

 

The other half of the class was instructed to create a fake sequence of 100 zeros and ones that's supposed to look like coin flips.

 

SIEGEL: And then you return from outside the room.

 

Professor GELMAN: Yeah. I returned and what I see is two blackboards, each with sequence of 100 zeros and ones, and I can immediately tell which is which.

 

SIEGEL: You can immediately tell which is the blackboard that represents a real series of 100 events.

 

Professor GELMAN: Right. A real sequence of coin flips is likely to have a long run of heads or tails. You're more likely than not to see a run of seven straight heads or seven straight tails. The fake sequence, they tend to alternate too much between heads and tails, so I can immediately see the fake one looks too random and the real one looks like something strange went on.

 

SIEGEL: The stranger the realer, as it turns out. It explains, in part, why some people are surprised by runs of chance and luck in reality and rush to supernatural, even miraculous explanations of things. ...

http://www.npr.org/templates/transcript/transcript.php?storyId=7320273

[sman]

My guess is that you have been reading "Rare Earth" by Ward and Brownlee

 

Rare Earth hypothesis - Wikipedia, the free encyclopedia

 

I havn't, but I'll check it out, thanks.

 

I guess my influences here would be Jarred Diamond, Ernst Mayr, Steven Pinker...not, BTW, simpletons. Mayr's objection to the Drake equation was something like that there are fifty million some-odd species on earth and only one of them has developed civilizations - so the Drake equation should be multiplied by an aditional 50,000,000. Something cosmologists at the time didn't really think of.

 

One reason I think this issue is distorted is that it has been front-ended by cosmologist & astronomers, like Drake and Sagan, when it really is the relm of biology.

 

 

ok. but since you said this is "unfounded fantasy" to ask about intelligent life off-world, then that would make this a thread for Silly Claims and not Space. ;) i don't "believe" anything about the answer to the question, rather i believe only that the question be reasonable & reasonably put. :Alien:

 

 

I agree. So, what are the chances of intelligent life off-world, close enough to us in space and in time to talk to us, and with any inclination at all to do so? And do these chances approach one in the number of particles in the universe X the number of seconds since existance? (or some such agreed upon rubicon beyond which we can dismiss as impossible)

 

Is that reasonable?

[Moontanman]

I think in this discussion it is important to point out that life on Earth is not some strange unlikely event, life appeared almost immediately after the earth's crust cooled enough for liquid water to have formed. The sun was much cooler then and it is reasonable to assume that Venus developed life as well and maybe even Mars.

 

Thomas Gold in his book "The Deep Hot Biosphere" seems to think that life developed deep within the Earth at temps and pressures we would think impossible for life but due to pressure chemicals act completely different than on the surface and water is a super critical liquid at very high pressures and temps. Such conditions probably prevailed on all of the terrestrial planets for part of their history. He sites gold and other metals being associated with Carbon deposits as evidence of this. Since some high temp microbes we already know of use metals as electron receptors and leave behind deposits of pure or relatively pure metals.

 

Even Silicon life, Gold postulates, could exist in such high pressure/temperatures, that exist even deeper using silicone oils as a working fluid since silicon behaves significantly different at such pressures and temps. He sites quartz crystals that are associated with gold and other metal deposits as evidence of this.

 

The point is Life is not an oddity or a rarity, as conditions on the Earth changed life changed as well eventually life began to influence the environment to it's own benefit. On Venus the sun's continued increase in energy out put overcame life's ability to adapt and a run away greenhouse doomed life on that planet.

 

On Mars loss of the atmosphere negated the benefits of increased solar energy, quite possibly the increase accelerated the loss of the Martian atmosphere. It's a pretty good bet that microbes still live in the deep under ground of Mars at least.

 

Quite possibly the silicon life still lives inside Venus (if it exits at all) but that will be difficult to confirm. The point is that life is not unusual and on the Earth (one of three) life continued to develop and as it did the complexity of Earth life increased as conditions for it improved eventually life it's self changed the environment to allow more and more complex life.

 

I do not think it's unlikely that a high percentage of planets that develop life eventually develop complex life. Lots of factors come into play and the Earth does in some ways appear to be charmed but there is no reason to think that all of the "special" circumstances that seem to help life on Earth need to be present for complex life everywhere.

 

Some calculations seem to indicate that even a large moon is not as unlikely as once thought, larger Earth type planets might even be more complex life friendly than the Earth. With more extensive magnetic fields, denser atmospheres and a higher rate of continental drift these super terrestrial planets might turn out to be super life worlds as well.

 

Still the question remains, intelligent technological life? I see no way to be sure other than contact of some kind but if it happened here i see no reason to think it didn't happen someplace else and if there are lots of complex life worlds then there are probably lots of technological life bearing planets as well.

[Moontanman]

I havn't, but I'll check it out, thanks.

 

I guess my influences here would be Jarred Diamond, Ernst Mayr, Steven Pinker...not, BTW, simpletons. Mayr's objection to the Drake equation was something like that there are fifty million some-odd species on earth and only one of them has developed civilizations - so the Drake equation should be multiplied by an aditional 50,000,000. Something cosmologists at the time didn't really think of.

 

I think that is totally unreasonable, almost none of those species had any chance to be intelligent, intelligence is not a random thing that just strikes like the lottery.

 

One reason I think this issue is distorted is that it has been front-ended by cosmologist & astronomers, like Drake and Sagan, when it really is the relm of biology.

 

The idea that intelligence is a random thing that just struck humans is not biological thinking. Life was not complex enough to attain intelligence until at the very least the last of the Cretaceous. some would say that as soon as intelligence could develop it did, I'm not sure that is supportable but to assume all life has an equal chance to be intelligent is simply wrong.

 

I agree. So, what are the chances of intelligent life off-world, close enough to us in space and in time to talk to us, and with any inclination at all to do so? And do these chances approach one in the number of particles in the universe X the number of seconds since existance? (or some such agreed upon rubicon beyond which we can dismiss as impossible) Is that reasonable?

 

Yes, but if intelligence is relatively rare, and I think it is, the nearest civilization could indeed be 10,000 light years away, 1000 at least even if intelligence is quite common.. If they are using light speed as a limit as we are, they are totally unaware of us and unless they want to be found we are totally unaware of them and likely to remain so.

 

The only fantasy i see here is the idea of an alien space ship landing on the Earth, unless they are the type that live in artificial colony type ships and are already pretty much everywhere I see no likely contact for many years to come.