Originally Posted by SF_Steve_63

The most adamant unilateral disarmament advocates who sprung up during the late 1T and really came out during the 2T certainly wanted all of us to believe what you wrote. I used to believe it myself. I no longer do. Believing it sets you up for certain slavery because it prevents any sort of real preparation for the great power geopolitical stage of The Crisis. Un prepared means ready to be conquered.

No matter how much you WANT to believe it isn't true, no matter how many reasons of desire such as you just presented why it isn't a good thing that it's true, these are not logical reasons why it ISN'T true.

It is true. If that means that we are "set up for certain slavery," then we are set up for certain slavery. End. Of. Story.

Anyway, you're wrong. Believing it doesn't keep you from being prepared. It just keeps you from being stupid and destroying the world.

I voted Prime Directive. I believe the aliens out there are "peacemakers" with a highly evolved demeanor and mentality who would only step in if some people got dangerous to the existence of the universe somehow.

Originally Posted by Traveler89

I voted Prime Directive. I believe the aliens out there are "peacemakers" with a highly evolved demeanor and mentality who would only step in if some people got dangerous to the existence of the universe somehow.

That still would not explain why we have not seen the obvious Infrared signatures of Dyson Spheres and Ringworlds. Or maybe we have and nobody has connected the dots between the "odd" looking stars, yet; It's a huge galaxy...

Originally Posted by Odin

That still would not explain why we have not seen the obvious Infrared signatures of Dyson Spheres and Ringworlds. Or maybe we have and nobody has connected the dots between the "odd" looking stars, yet; It's a huge galaxy...

The way I see it is if they have the technology to visit us or even know we exist they most likely have some crazy technology to make themselves and their signals invisible at an advanced level that we can't even comprehend yet. Because to travel across the entire universe would require something much more advanced than a standard fuel or energy source.

Originally Posted by Brian Rush

No matter how much you WANT to believe it isn't true, no matter how many reasons of desire such as you just presented why it isn't a good thing that it's true, these are not logical reasons why it ISN'T true.

It is true. If that means that we are "set up for certain slavery," then we are set up for certain slavery. End. Of. Story.

Anyway, you're wrong. Believing it doesn't keep you from being prepared. It just keeps you from being stupid and destroying the world.

Well, no matter what the Saganian peaceniks would opine, the Left's beloved Obama has invested more energy into perfecting Oplan 8080 (nee "the SIOP") than any President since Reagan. Lots of activity planned especially for Fall and Winter.

Originally Posted by SF_Steve_63

Well, no matter what the Saganian peaceniks would opine, the Left's beloved Obama has invested more energy into perfecting Oplan 8080 (nee "the SIOP") than any President since Reagan. Lots of activity planned especially for Fall and Winter.

As I said above.

You still have not presented one single cogent argument why I'm wrong. You've presented reasons why, morally and ideologically, I should be wrong. You've said why it's better for liberty and justice and little cuddly kittens if I'm wrong. But you've presented no reason at all to believe that I actually am. If you want to refute what I've said, don't say how much Obama is spending on the military (that's irrelevant), and don't spout stuff about how believing this will condemn us to certain slavery (that's also irrelevant), show how a full-scale nuclear war can be fought without bringing an end to civilization.

That's the ONLY argument that could ever be relevant. And you have not presented it, or even tried to.

Setting wishful thinking aside, the most likely answer to the poll question is "slow boat." We don't know for certain of any way to travel faster than light. That explanation suffices, and it's true as far as we know.

I don't like setting wishful thinking aside, and so I answered "prime directive" which I do believe to be the second-most-likely explanation. That's the reason why we haven't seen them if they can get here. But I do realize that wishful thinking is the only good reason I have to believe that they might be able to.

The one thing I'm completely certain about, though, is that Rare Earth is wrong.

Originally Posted by Brian Rush

The one thing I'm completely certain about, though, is that Rare Earth is wrong.

It depends on how you interpret the poll's definition of Rare Earth. It says: We are the one of the very few habitable planets in the galaxy. I decided to add: that has life technologically advanced enough for interstellar communication/transportation. I believe that life, in some form, is common in the galaxy, but not technologically advanced life. If Rare Earth is supposed to mean we are one of the only planets with life of any form, then I would change my answer to Naked Ape. Although even with Naked Ape I would tweak it to: Intelligence inventing advanced technology is not inevitable.

"If there are exploration-minded alien civilizations, thenwe should have a record of encountering them."

I've thought about this and well....there's a flaw because why would we assume that they want to interact with us in the first place? What do we have to offer them? What if our presence is so small that we have gone undetected by other life forms from other planets, or we're considered so insignificant that we aren't worth their time and energy.

The resources we might have in our solar system, specifically on our planet, could probably be found in a system closer to theirs. So what could we have that they might want? It could be costly for their race to embark on some type of expedition to visit a far away planet in another solar system.

I suppose they could enslave us but we're such a small population of life, what would be the point? Or perhaps they would like to learn from us, but...if they're so intelligent that they can travel, what would they learn from us?

I guess they could study us like bugs under a microscope, if that's the case than...who says they haven't visited our planet. if they're so intelligent that they can travel through space to our planet, then I can imagine that they would to to great lengths not to be noticed.

Originally Posted by Erik '73

It depends on how you interpret the poll's definition of Rare Earth. It says: We are the one of the very few habitable planets in the galaxy. I decided to add: that has life technologically advanced enough for interstellar communication/transportation. I believe that life, in some form, is common in the galaxy, but not technologically advanced life.

THAT is what I'm absolutely certain isn't true. I explained why above. It remains possible, though it seems to me unlikely, that we may be rare in the emergence of life, but where there is life there will inevitably be intelligent life.

I explained my reasoning in detail in #11. If we look at the history of life here, we find that as soon as the conditions were ripe for any step along the road towards intelligent life, that step happened very quickly. Probability of it happening went from zero to something fairly respectable. For example, life's beginning had a probability of zero until the planet had liquid water, and as soon as it did, life emerged within a few hundred million years. Similar observation with the emergence of photosynthesis, of eukaryotes, of candidate intelligence, of human intelligence. No step along this road was possible -- each had zero probability -- before certain other developments occurred, and once they did occur the advance appeared in a very short time.

Progress towards high technology after the emergence of human intelligence has been even more rapid. Our species is less than 200k years old. That's the blink of an eye in evolutionary terms.

Originally Posted by Felix5

I've thought about this and well....there's a flaw because why would we assume that they want to interact with us in the first place? What do we have to offer them? What if our presence is so small that we have gone undetected by other life forms from other planets, or we're considered so insignificant that we aren't worth their time and energy.

The 'undetected' possibility is something I could buy. Buy as to why one that could would necessarily want to interact with us (or even look for us in the first place)? That's simple.

Because new stuff is cool. Such a perspective on the world around them is a constant in all the intelligent and semi-intelligent lifeforms of which we are aware. Given the nature of what we mean when we talk about 'intelligence', curiosity -- and more important a fundamental drive that rewards acting upon curiosity -- seems very much to be an inevitable parts of it. What's more, if we are talking about a creature that has developed the capacity to look and travel outside its own native biosphere, then we're talking about a thing that has developed something resembling science. Again, evidence of a drive to search for new thing to poke at and ways to poke at them better.

Really, of all the reasons possible why another intelligence would fail to interact with us, lack of interest on their part is probably the only one that's simply not even remotely likely.

Originally Posted by TimWalker

anti-exponential theory

This article makes a very good point, and shows that a major assumption of the Fermi Paradox--that any and all intelligent life would (of course!) spread and multiply exponentially and indefinitely like some culture in a huge Petri dish--most certainly needs reviewing and should probably be discarded. "Slow boat" need not mean just limitations on speed of travel, but simply no desire (or need) to expand all that quickly in the first place. Quality of life and civilization would more likely become more of an issue of an advanced intelligent race, than just continuing to amp up the quantity full tilt.

Of course we cannot assume one general way of thinking for any of a possible multitude of intelligent races as may exist, but physical sustainability limits also come into play as the article mentions. I've always had a feeling that the "Fermi Paradox" made too many assumptions about how intelligent races would necessarily operate regarding interstellar expansion. It's not like we're anywhere close to that point ourselves yet, and expansion through dead space hardly parallels expansion across a living planet--so there is not even a real human model to look to in this regard (thus not even one example in this universe that we have been able to observe, yet--and yet we make these huge assumptions about how it would be done).

That's part of my reasoning, actually. Like war, exponential expansion is something that must be changed before a civilization can achieve interstellar travel. If we cannot end our own exponential expansion and achieve a sustainable culture within the limits imposed by resources on this planet, we will self-destruct before we can ever expand. Expansion into space is necessarily going to be slow, barring radical redesign of the human physical vehicle, because as we exist today as living organisms we are dependent on a biosphere for long-term survival. We can survive in space temporarily only by expending more resources than we would if we stayed home. In order to permanently colonize other parts of space beyond the Earth, we must transport not just ourselves and our civilization but also reproduce the terrestrial biosphere in sufficient completeness for ecological sustainability. In other words, we have to terraform other planets. Doing that would be a massively capital-intensive and time-consuming project with a big ultimate payoff in increased resources and living space, allowing controlled -- not uncontrolled -- population growth. Whether we would find it worth doing is a good question, but we certainly aren't going to expand into space the way our ancestors did across the planet. Exponential growth is possible, up to a limit, within a biosphere but not outside it.

Any advanced civilization capable of interstellar travel will be ecologically conscious and have a sustainable society, and will not be warlike. Failure to achieve either of these things results in self-destruction before interstellar travel becomes technically possible.

Because new stuff is cool. Such a perspective on the world around them is a constant in all the intelligent and semi-intelligent lifeforms of which we are aware. Given the nature of what we mean when we talk about 'intelligence', curiosity -- and more important a fundamental drive that rewards acting upon curiosity -- seems very much to be an inevitable parts of it. What's more, if we are talking about a creature that has developed the capacity to look and travel outside its own native biosphere, then we're talking about a thing that has developed something resembling science. Again, evidence of a drive to search for new thing to poke at and ways to poke at them better.

Yea but this is true for us, but maybe not so much for other intelligent life. Perhaps we aren't anything new or special

Really, of all the reasons possible why another intelligence would fail to interact with us, lack of interest on their part is probably the only one that's simply not even remotely likely.

And we know this...how? We don't know anything about life outside of our planet, in fact we still don't understand life on this planet.

Curiosity is an inherent feature of intelligence. It is impossible to be intelligent and non-curious, for the same reason it's impossible to be both in top athletic condition as a marathon runner and severely overweight.

I think civilizations almost immediately turn completely inward. I think the dreams of galactic spread are pretty silly in the face of just turning to inward realities, where you want dense computational structures.

High tech civs are probably super-dense computational superstructures that recycle almost all their energy. They probably look like brown dwarves, or dead stars.

The actual universe is only so interesting when compared to the vast possibilities of computational simulation.

If you want to explore it, send out tiny, tiny probes.

I fail to see how there is a paradox. Let's assume for the sake of argument that to travel to another solar system would require moving through Einsteinian space to get there--no "cheating technology" like warp drives that lets one travel faster than light at a tiny fraction of the energy cost needed to travel in the normal way.

Given this very plausible assumption it is clear that the energy requirements needed to travel at a high rate of speed are very large compared to the energy costs of operating in space within one's own solar system. For example, for the energy cost of sending just one manned spaceship to another star, one could put tens or even hundreds of millions of people into space habitats orbiting the sun, or terraform entire worlds.

A civillization capable of interstellar travel has the capability to do very impressive things right at home, so why go?

Even if the goal is simply curiosity, this can be achieved using a tiny robotic craft instead of a ship carrying people. Such a ship might well be 100 millions times cheaper then sending people. Such a tiny craft could even be here and we would never know it.

I see no situation in which aliens would go to the tremendous expense of physically moving themselves to our solar system, when they could more easily accomplish anything achievable by such a trip by not going. So I think most alien civilizations would not bother coming in the first place, and even any that did come would never be detected, unless they wanted to be.

I can imagine some might want to make contact. All that is needed to explain lack of contact is that civilizations currently capable of and interested in interstellar travel for contact purposes, are simply not located nearby, and so any planets they do visit won't be ours. And all that is needed for this to be true is that such civilizations are quite rare, in which case it is far more likley that they are far away than close by.

So the Fermi paradox is exactly what one would expect even with a universe full of intelligent life.

Originally Posted by Mikebert

I fail to see how there is a paradox. Let's assume for the sake of argument that to travel to another solar system would require moving through Einsteinian space to get there--no "cheating technology" like warp drives that lets one travel faster than light at a tiny fraction of the energy cost needed to travel in the normal way.

Given this very plausible assumption it is clear that the energy requirements needed to travel at a high rate of speed are very large compared to the energy costs of operating in space within one's own solar system. For example, for the energy cost of sending just one manned spaceship to another star, one could put tens or even hundreds of millions of people into space habitats orbiting the sun, or terraform entire worlds.

A civillization capable of interstellar travel has the capability to do very impressive things right at home, so why go?

Even if the goal is simply curiosity, this can be achieved using a tiny robotic craft instead of a ship carrying people. Such a ship might well be 100 millions times cheaper then sending people. Such a tiny craft could even be here and we would never know it.

I see no situation in which aliens would go to the tremendous expense of physically moving themselves to our solar system, when they could more easily accomplish anything achievable by such a trip by not going. So I think most alien civilizations would not bother coming in the first place, and even any that did come would never be detected, unless they wanted to be.

I can imagine some might want to make contact. All that is needed to explain lack of contact is that civilizations currently capable of and interested in interstellar travel for contact purposes, are simply not located nearby, and so any planets they do visit won't be ours. And all that is needed for this to be true is that such civilizations are quite rare, in which case it is far more likley that they are far away than close by.

So the Fermi paradox is exactly what one would expect even with a universe full of intelligent life.

So far the closest non gas giant is a heat blasted sphere of slag ~30 LY away. Indeed, not much incentive here. Until / unless someone can demonstrate something beyond Einsteinian energy balance considerations, I must agree with your assessment.

Originally Posted by SF_Steve_63

So far the closest non gas giant is a heat blasted sphere of slag ~30 LY away. Indeed, not much incentive here. Until / unless someone can demonstrate something beyond Einsteinian energy balance considerations, I must agree with your assessment.

Now that you brought this up, it is unlikely that sol-like systems are very common, considering we have discovered over 400 extrasolar planets, none of which are in systems resembling our own. And it is also clear that the metalicity of our sun is on the high end, suggesting that only a minority of sun-like stars would have the right sort of planets. Furthermore only a minority of these would have life and only a minority of those would have intelligent life. Based on a quickie census I did of close-by stars, about 6% are G-class. If we assume 1% of these have Earth-like planets with life this would suggest one planet with life for every 1666 stars, putting the closest one around 50 light years away or so.

Only a fraction of these (probably a tiny fraction) would have intelligent life capable of interstaellar travel and interested in doing so. Let's be very generous and assume 1 out of 1000 such planets have interstellar-capable civilizations. With these assumptions our galaxy alone would have on the order of 100,000 space-faring civilizations, that is, lots and lots of them. Even so, the closest one would be around 500 light years away. When they look at Earth the light they see would have left Earth 500 years ago, long before any evidence of intelligence appearred such as recent very rapid rise in CO2 levels or radio signals. There would be nothing to mark the Sol system as special and so no reason to come here as opposed to any of hundreds of apparently similar worlds much closer to them. Now a 900 years from now, we will have announced our presence over a sphere 2000 light years across, in which case potential inhabitants of more than 12 million stars would have had a chance to see evidence of intelligent life here and so possibly some one would make the trip. So maybe they will come in the future. But right now is way too soon.

Originally Posted by Mikebert

Given this very plausible assumption it is clear that the energy requirements needed to travel at a high rate of speed are very large compared to the energy costs of operating in space within one's own solar system. For example, for the energy cost of sending just one manned spaceship to another star, one could put tens or even hundreds of millions of people into space habitats orbiting the sun, or terraform entire worlds.

Untrue. The energy cost does not increase with distance. One expends energy to accelerate to top speed and again to decelerate on entering the new star system. In between, one proceeds on inertia without expending any energy except to survive.

Originally Posted by Mikebert

Furthermore only a minority of these would have life and only a minority of those would have intelligent life.

The first part of this sentence (scarcity of life) may or may not be true. The second part (intelligent life being rare in biosystems) is almost certainly untrue.

Based on a quickie census I did of close-by stars, about 6% are G-class. If we assume 1% of these have Earth-like planets with life this would suggest one planet with life for every 1666 stars, putting the closest one around 50 light years away or so.

This much is quite plausible and probably close to accurate.

Only a fraction of these (probably a tiny fraction) would have intelligent life capable of interstaellar travel and interested in doing so.

This however is almost certainly false. Of the one star in ~ 2000 having biospheres, all of them would have intelligent life capable of interstellar travel (with or without cheating) except those that were relatively new (like us) and those that had self-destructed. Life may or may not be rare, but given life, intelligence is a certainty.

Insteller Cyclers. I have to wonder if there is a catch - lack of coordination, due to messages being limited to the speed of light.

I know I sound like a broken record here, but there are some compelling illusions about how rare intelligence must be, and it's an interesting exercise to penetrate and dispel those illusions.

The first illusion involves how much time it took from the beginning of life until the evolution of H. sapiens. Life is some 4 billion years old, while our species has existed for only .002 billion years at most, so it took four billion years for us to emerge. That makes it look like a low-probability event, if you think of nature starting to roll dice 4 billion years ago and only finally hitting the right combination in the last evolutionary eyblink of time. The second involves tracing the events in evolution that led to the emergence of our species and noting how extremely improbable we are.

The reason the first is an illusion is a specific iteration of the general point that you have to date the amount of time it took for any evolutionary development to happen, not from the beginning life, but from the point when it became possible for that development to happen. One-celled organisms don't have a very low probability of morphing into intelligent organisms capable of space flight, they have a zero probability. Before a species like ours can evolve, there must exist at least one less intelligent species that uses manipulation of the environment and social organization as its survival strategy. Earth currently has many such species: all of the primates, several other mammal species, and several species of bird. The animal family group that eventually bred man (primates) appeared some 40-50 million years ago, and so that's how long the evolution of our species took from sub-sapient intelligence. As for sub-sapient intelligence itself, that emerged (probably for the second time) within 15-25 million years after the K/T extinction, so that was pretty rapid as well in evolutionary terms.

In other words, neither of these developments is low-probability. Without the evolutionary prerequisites, they are zero-probability; with them, they are high-probability. The same is true for all other steps along the evolutionary line before that, with the possible exception of the emergence of life itself.

The other illusion involves a confusion of the pertinent question. The question isn't "how likely was it that H. sapiens evolved?" The question is, "how likely was it that some species or other with basically the same abilities as H. sapiens evolved, whether us or something else?" The emergence of our own species specifically was of course a complete fluke and one should not expect it to be duplicated exactly anywhere. But the emergence of some species capable of doing what we can do (more or less) was a high probability event. It didn't have to be us, but it did have to be something.

Further discussion of interstellar cyclers. Of course, there is the difficulty of reaching half of light speed - if that should prove to be impractical, will cyclers be limited to a much more constrained range?

Originally Posted by Brian Rush

Untrue. The energy cost does not increase with distance. One expends energy to accelerate to top speed and again to decelerate on entering the new star system. In between, one proceeds on inertia without expending any energy except to survive.

I was referring to the energy needed to accelerate and decelerate. It is very large compared to other tasks to which that energy could be put.