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Thread: What do you think is the most likely explanation for the Fermi paradox?

  1. #1021
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    Quote Originally Posted by Roger E. Moore View Post
    The Jews in underground groups and in Warsaw would disagree.
    The ones from Germany would not.

    Afghanistan War.
    Still missing the point. Genocidal policies were first enacted inside the nations in question, on lands that were already under their power. The area of controlled territories spread by invasion, which is not IMO a plausible scenario over interstellar regimes.
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  2. #1022
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    Quote Originally Posted by Roger E. Moore View Post
    No, but it is a necessary assumption for the discussion, that they are social, organized, and tool-using. That's what makes the argument interesting: why, if they have similarities to us, are they not at least talking.
    If they are social enough to build starships, it makes sense that they have something inherent to maintain social cohesion; empathy, or something like it. A species of sociopaths could not maintain a civilization.
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    Quote Originally Posted by Noclevername View Post
    If they are social enough to build starships, it makes sense that they have something inherent to maintain social cohesion; empathy, or something like it. A species of sociopaths could not maintain a civilization.
    Agreed, but they do not have to be sociopaths. You do not have to be sociopathic to take part in destroying another culture. You just have to be certain your side is right, and everything you do is okay because it helps your side win. Also, the other side is not as good as yours, and to you it looks obvious. Sociopathy need not apply. Just bigotry and self-righteousness.
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  4. #1024
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    Quote Originally Posted by Roger E. Moore View Post
    Agreed, but they do not have to be sociopaths. You do not have to be sociopathic to take part in destroying another culture. You just have to be certain your side is right, and everything you do is okay because it helps your side win. Also, the other side is not as good as yours, and to you it looks obvious. Sociopathy need not apply. Just bigotry and self-righteousness.
    We are not talking about cultural changes or colonialism. We are talking about deliberately building and deploying a weapon of mass destruction with the set purpose of wiping out an entire world and every last mind on it. It's not something that will be done off-hand or by arrogance or a sense of entitlement. It is a choice.
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  5. #1025
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    Quote Originally Posted by Noclevername View Post
    The ones from Germany would not.
    Not true.
    https://encyclopedia.ushmm.org/conte...ish-resistance

    Still missing the point. Genocidal policies were first enacted inside the nations in question, on lands that were already under their power. The area of controlled territories spread by invasion, which is not IMO a plausible scenario over interstellar regimes.
    Genocide against native Americans was enacted in lands to which English and Spanish and other nations' colonists migrated, not first inside their own countries.

    And if small groups of aliens with enormous power (which is a given if they are using interstellar travel) can take over a solar system with a low-tech civilization on a desireable planet, why can't they wipe that low-tech culture out?
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    Quote Originally Posted by Noclevername View Post
    We're close enough in delta-V to several large Near Earth Asteroids that we can claim and use before aliens spread too far. That gives us a foothold that we can expand on.
    Not sure interstellar aliens would be slowed down by finding a few Earth people trying to claim a valuable asteroid.
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  7. #1027
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    Quote Originally Posted by Roger E. Moore View Post

    And if small groups of aliens with enormous power (which is a given if they are using interstellar travel) can take over a solar system with a low-tech civilization on a desireable planet, why can't they wipe that low-tech culture out?
    I don't think they can "take over a Solar System". It's just too big a volume for a small group to entirely police without resistance. We will do something. Probably, given the divided nature of humans, we would do many things. But the most obvious step is, we'd vastly increase our presence in space and damn the cost. We'd try to claim as much of our own space as possible before they can get their tentacles on it.

    We've got an entire world of resources, personal and material. They've got whatever they can bring with them across what is literally the hardest and most energy-intensive journey physically possible. No, they'd not automatically have all the power just because they have advanced tech. Ask the Mujahedeen about that.
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  8. #1028
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    Quote Originally Posted by Roger E. Moore View Post
    Not sure interstellar aliens would be slowed down by finding a few Earth people trying to claim a valuable asteroid.
    Not sure we'd be reluctant to do much more than that to defend what we see as ours.
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    Quote Originally Posted by Noclevername View Post
    We've got an entire world of resources, personal and material. They've got whatever they can bring with them across what is literally the hardest and most energy-intensive journey physically possible. No, they'd not automatically have all the power just because they have advanced tech. Ask the Mujahedeen about that.
    But they would have the high ground and the technology. Drop a few asteroids on Earth and we would cease to be a credible threat to them. Even if we use interplanetary capable rockets to carry nukes, we would be unlikely to hit anything of theirs that matters unless they pay no attention to defense.

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  10. #1030
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    Quote Originally Posted by Van Rijn View Post
    But they would have the high ground and the technology. Drop a few asteroids on Earth and we would cease to be a credible threat to them. Even if we use interplanetary capable rockets to carry nukes, we would be unlikely to hit anything of theirs that matters unless they pay no attention to defense.
    There's some confusion here. I was addressing post #1011 where the aliens just came in and annexed the asteroids while ignoring us. So I started with that scenario. The most likely outcome of that would be a Space Race of "who's got the most stuff". It could and probably would eventually develop into violent conflict but that wasn't the starting point.

    If the aliens' goal was to destroy us they need not invade to do it. Remote methods are far less of a risk and potentially more reliable. Beyond that, there's no reason to colonize an already inhabited system; the Universe is full of empty real estate with the exact same resources. The safest choice for colonists would be to skip over us and settle elsewhere.
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    Okay, so your assumption is that they start by ignoring us, and when we attack them they allow us to continue with impunity? It’s a possibility, I suppose but I see no reason they would just let us drive them away when they have the means to stop us.

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  12. #1032
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    Quote Originally Posted by Van Rijn View Post
    Okay, so your assumption is that they start by ignoring us, and when we attack them they allow us to continue with impunity? It’s a possibility, I suppose but I see no reason they would just let us drive them away when they have the means to stop us.
    Not what I said. At all.

    The scenario was Roger E Moore's not mine. That was that the aliens settled here and began a land grab without engaging us.

    To clarify; I think once the conflict became direct, they'd fight. But by then, we might have already put defenses in place off Earth before engaging them directly. Take advantage of them ignoring us for as long as possible. If we're smart. Up until that point though, the job would be to establish our own offworld capabilities while avoiding bodies they've already taken.
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    I’m looking at it like a group of people building something, especially as in an out of the way place, like Alaska wilderness or similar. They know there are animals around and take precautions but don’t get too concerned until the animals start becoming pests or outright attack them, and then they respond. With aliens you would have to hope they see some merit to leaving Earth as a sanctuary for native species and just destroy any ships we put into orbit.

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  14. #1034
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    Quote Originally Posted by Van Rijn View Post
    I’m looking at it like a group of people building something, especially as in an out of the way place, like Alaska wilderness or similar. They know there are animals around and take precautions but don’t get too concerned until the animals start becoming pests or outright attack them, and then they respond. With aliens you would have to hope they see some merit to leaving Earth as a sanctuary for native species and just destroy any ships we put into orbit.
    Well, if they're enough like us to have a spacefaring civilization, communication is a distinct possibility. So they might not consider us animals.

    Which could be good or bad.
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    Going back to the Dark Forest, it seems unlikely to me as an explanation for alien absence.

    In short, what about the winners?

    A civilization that can build an interstellar weapon to wipe a world can easily colonize multiple star systems. Especially if they're now certified empty territory! So an expansive species who carried out such a policy would have no reason not to spread as much as a less genocidal one. They just scorch their way across space and settle in the ashes.
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    Quote Originally Posted by Noclevername View Post
    Predators do not wipe out their prey. That would be ...unwise. Modeling genocide on predator-prey relationships is not rigorous logic.
    A bit off topic, but I think there is a balance, where as the number of prey decreases, it requires more energy to catch them, and predators die off as well, and somewhere there is an equilibrium.
    As above, so below

  17. #1037
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    Quote Originally Posted by Van Rijn View Post
    I’m looking at it like a group of people building something, especially as in an out of the way place, like Alaska wilderness or similar. They know there are animals around and take precautions but don’t get too concerned until the animals start becoming pests or outright attack them, and then they respond. With aliens you would have to hope they see some merit to leaving Earth as a sanctuary for native species and just destroy any ships we put into orbit.
    Yes, this scenario was the possibility I was thinking about.
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  18. #1038
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    Quote Originally Posted by Noclevername View Post
    Going back to the Dark Forest, it seems unlikely to me as an explanation for alien absence.

    In short, what about the winners?

    A civilization that can build an interstellar weapon to wipe a world can easily colonize multiple star systems. Especially if they're now certified empty territory! So an expansive species who carried out such a policy would have no reason not to spread as much as a less genocidal one. They just scorch their way across space and settle in the ashes.
    True.
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  19. #1039
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    Quote Originally Posted by Noclevername View Post
    The scenario was Roger E Moore's not mine. That was that the aliens settled here and began a land grab without engaging us.

    To clarify; I think once the conflict became direct, they'd fight. But by then, we might have already put defenses in place off Earth before engaging them directly. Take advantage of them ignoring us for as long as possible. If we're smart. Up until that point though, the job would be to establish our own offworld capabilities while avoiding bodies they've already taken.
    We could do that, but over time the balance of power will tilt in favor of the aliens, who can build on the resources of the rest of the solar system. Defending the Moon and a few asteroids would be our last hurrah.
    Do good work. —Virgil Ivan "Gus" Grissom

  20. #1040
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    Quote Originally Posted by Roger E. Moore View Post
    We could do that, but over time the balance of power will tilt in favor of the aliens, who can build on the resources of the rest of the solar system. Defending the Moon and a few asteroids would be our last hurrah.
    Why could we not also expand into the Solar System? We'd be starting from a much larger base population and developed industrial capacity. A forest vs a seed.
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  21. #1041
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    Quote Originally Posted by Roger E. Moore View Post
    We could do that, but over time the balance of power will tilt in favor of the aliens, who can build on the resources of the rest of the solar system. Defending the Moon and a few asteroids would be our last hurrah.
    There's plenty of room and materials in the Solar system as a whole to share. They can't claim the whole thing, it's too vast in scale.

    I think if they had a policy of ignoring us, it'd be for a reason. Maybe they want to avoid conflict or preserve the natives or just don't care. Whatever the cause, it means war and extermination of a potential threat are something to be avoided for them.

    So why would we be in conflict? There's plenty of Oort Cloud bodies that we can't use anyway. Easier by far to move away than to engage in a destructive battle. And moving is well within their capacity if they can manage to cross between stars. Harder for us, though.

    So we end up with the inner worlds we can reach, and they get everything else. Genocide averted.
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    Quote Originally Posted by Noclevername View Post
    There's plenty of room and materials in the Solar system as a whole to share. They can't claim the whole thing, it's too vast in scale.

    ...So we end up with the inner worlds we can reach, and they get everything else. Genocide averted.
    Unless they have a long-range policy of having no competition. It's an interesting option. If the aliens can shut down space travel for humans, as they might have done with other races they've met, humans would find themselves on an enforced reservation. You can have Earth, the aliens say right from the start, but everything else is ours. We might not use it right away, but we think in time we will need it. No planet-busting weapons needed, no invasion, just shooting down a few primitive spacecraft and starting the process to convert the solar system into yet another Dyson Sphere. Unless we get rowdy and they drop a few rocks on us.

    I'll leave it at that. I admit I am not particularly married to the Dark Forest hypothesis, but the concept that we could lose everything but Earth is a disturbing one, even if we are left to live our lives here.

    Likelihood it will happen: Meh. Just an interesting speculation.

    I still say, don't alert any Dyson Sphere we find as to our location.
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  23. #1043
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    The Zoo Hypothesis, in other words. Not one I think likely either. It requires an attitude I think of as specifically human, and not even common to all human cultures.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by swampyankee View Post
    If we get evidence off the presence or absence past life on Mars (even with human explorers actually on Mars, this is likely to be non-trivial), we may get some idea of the likelihood of abiogenisis. Once we get that, the argument will get more interesting, as there will be more data.

    Positing a considerable period of active searching, there are a few possibilities (I'm ignoring the possibility of a false negative. Until there has been enough examination -- say until at least 15% of Mars' surface is investigated to a depth of a meter or so -- stating life never existed on Mars is likely premature)
    1) There's never been life on Mars.
    2) There was life, to the approximate equivalent to prokaryotes.
    3) There was life, to the approximate equivalent to eukaryotes
    4) There was life, to the approximate equivalent of multicellular organisms
    5) There are relics of intelligent life (which I think is extremely unlikely)
    6) There is remnant life. I don't think this is impossible, as prokaryotes have been found in subterranean strata over a kilometer beneath the surface.
    7) There's an active ecosystem including autotrophs and heterophs. While I don't think this is impossible, I think it's extremely unlikely.


    The first five give some information to quantify one or two of the factors in the Drake equation (the ones concerned with the number of planets and habitable planets have some quantification due to the discovery of exoplanets. When Drake conceived this equation, even those were largely data-free). Obviously, relics of intelligent life would be the most surprising and could move the Fermi paradox into something interesting from a rather minor question.
    I'd agree that past microbial life on Mars is quite plausible, and is an intriguing possibility. But it is very difficult (whether on Mars or Earth) to show conclusively that a particular mineral formation was produced by ancient microbes rather than by a non-biological process.

    Current life on Mars is not impossible, but is arguably less likely than current life on Titan and in the clouds of Venus. The thing is, Mars' atmosphere is less chemically active than the other two worlds I've mentioned.

    Life chemistry is active chemistry — it's not enough to have suitable chemical building blocks, they have to be reacting together or else you don't have life.

    This is not to say that there will be life everywhere there is chemical activity. Every theory of abiogenesis I've seen agrees that chemical activity came first. Life emerged from chemical activity and caused it to continue in new forms.

    So it's quite likely we'll find some chemically active worlds without life, however not so likely we'll find life on a chemically quiescent world.

    (This line of reasoning is not my own work, it is what David Grinspoon calls the "living worlds hypothesis". See his book "Lonely Planets".)
    Last edited by Colin Robinson; 2021-Jan-01 at 12:08 AM.

  25. #1045
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    Quote Originally Posted by Colin Robinson View Post
    Every theory of abiogenesis I've seen agrees that chemical activity came first. Life emerged from chemical activity and caused it to continue in new forms.

    So it's quite likely we'll find some chemically active worlds without life, however not so likely we'll find life on a chemically quiescent world.
    Mars wasn't always inactive, though. It had a warmer thicker atmosphere and liquid water. Life could have developed there and adapted to the losses, perhaps underground or in polar ice. I personally doubt that's the case but it isn't something to rule out entirely.
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    Quote Originally Posted by Noclevername View Post
    Mars wasn't always inactive, though. It had a warmer thicker atmosphere and liquid water. Life could have developed there and adapted to the losses, perhaps underground or in polar ice. I personally doubt that's the case but it isn't something to rule out entirely.
    I agree that current life on Mars can't be entirely ruled out.

    David Grinspoon's argument is that Mars isn't the most likely place in the Solar System to find life beyond Earth.

  27. #1047
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    Mars does have a history of open oceans, volcanoes, and sunlight just like Earth, if less intense. Venus too. We already have examples of life that exists inside ice or underground. So it's more likely in my opinion than some other choices.
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    Quote Originally Posted by Noclevername View Post
    Mars does have a history of open oceans, volcanoes, and sunlight just like Earth, if less intense. Venus too. We already have examples of life that exists inside ice or underground. So it's more likely in my opinion than some other choices.
    When you say "than some other choices", which do you have in mind?

    I'd agree that current life on Mars is more likely than life on Mercury...

  29. #1049
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    Quote Originally Posted by Colin Robinson View Post
    When you say "than some other choices", which do you have in mind?

    I'd agree that current life on Mars is more likely than life on Mercury...
    Venus and Titan were mentioned.

    I'm not sure about the ice moons. There may have been a role for sunlight in the chemistry of Earth's abiogenesis.
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  30. #1050
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    Quote Originally Posted by Noclevername View Post
    Venus and Titan were mentioned.
    Do you think Venus is less likely for life than Mars? Why?

    I'm not sure about the ice moons. There may have been a role for sunlight in the chemistry of Earth's abiogenesis.
    Glad you mentioned sunlight and abiogenesis.

    It's true that the ice moons including Titan get a lower flux of energy from the sun than Earth or Mars.

    But due to the composition of Titan's atmosphere (hydrogenating rather than oxidising), it's able to turn a substantial part of the solar energy it gets into chemical energy. E.g. by producing acetylene (C2H2) alongside free hydrogen (H2) in its ionosphere. This is comparable to what happened in the Urey/Miller experiment, and to what presumably happened in Earth's atmosphere 4 billion years ago, when abiogenesis occurred.

    That's one reason I think Titan may tell us more than Mars about questions like how common or uncommon abiogenesis is throughout the Galaxy.

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