Assuming intelligent aliens, they know this model.
Assuming stable state alien civilizations, they have countermeasures.
Grabby Aliens might discover immune system against cancer-like civilizations growing without limit. It should hit them early before they are metastasized.
Grabby Aliens might foresee immune system even before they encounter resistance. They might try stealthy expansion, gradual probing first strategy, or modify their behavior in order to survive, .... and so on.
This essentially is the Dark Forest hypothesis explanation for the Fermi Paradox. Civilizations work to avoid drawing attention to themselves because might be exterminated as potentially cancerous if detected
The assumption that seems most unlikely is that civilizations will simply stop expanding when they encounter another one. Even if most civilizations would stop, a single aggressive one would quickly dominate. Especially under the assumption that they can expand at a large fraction of the speed of light, a defender would have little ability to organize a defense before being overrun.
If we change our assumptions about whether they live on or even care about planets it becomes a very different story. Who knows if they even need the free energy that stars emit. Most of the interstellar medium is ionized so it may be that it’s much easier to just scoop up gas and dust with magnetic fields than it is to attempt to extract large quantities of matter from planets that are few and far between not to mention gravitationally bound.
What does a war between two nuclear-capable nations look like? If they can nuclear bombs, doesn’t that mean their first strike weapons are all nation killers? If we assume they still primarily use cities as the sites of their industrial and population centres then doesn’t that mean any city within striking distance are immediately obliterated by large, dark, unstoppable projectiles? Any point defence you can think of fails when you can easily throw thousands of these at a nation. There’s no way to win that game for either side.
So as you said, maybe the solution to the Fermi Paradox is that every surviving civilization is hiding in cloaked habitats within the vastness of intergalactic space.
I think if you look ahead at feasible technology, you get self-sustaining pure-space civilizations long before you get civilizations that can launch relativistic planet killers.
(The other problem with the "planet killer" hypothesis, as we've discussed in other HN conversations, is that there's no reason to wait until there's a civilization on the other end to launch one, given how fast they can pop up. As soon as you see life, you should launch one. But Earth has been broadcasting fairly conclusive proof that a civilization with just a bit more tech than we have now is alive ever since the Great Oxygen Catastrophe, yet nobody has killed Earth.)
This is more dangerous. If weapons are absolutely but selectively destructive - I can wipe your planet out quickly before you have time to respond and my planet is just fine - it incentivizes me to attack first and hunt down other potential threats and destroy them before you or they destroy me.
Would this affect their model, though? If either of the two civilizations dominates, rather than both being obliterated through mutual destruction, you would expect to see the same thing: that volume of space time is now occupied by a civilization. I’m not sure it matters which one (to their model, of course it would presumably matter to the inhabitants) — and either would be visible and have the effect described in the paper.
Also, one civilization dominating wouldn’t mean that the other one would magically disappear. As a simple assumption, I can imagine the stronger civ expanding into the territory of the weaker one relatively unhindered (in terms of expansion speed). But the weaker civ would still expand outwards as well. If it’s expansion speed isn’t slower, it would continue to grow in absolute size.
Every volume contains only a certain amount of potential free energy that can be used before the end. That’s what you fight over. Dyson Spheres, fusion, antimatter, these are all details. Everybody wants negentropy and it’s a zero sum game.
If a civilization is spread out in a 10000 light year area and encounters another in one place it seems impossible they could make a collective decision given the amount of communication that it would take.
This implies a lot of things though - let us say we expand to Mars and manage to terraform it somehow - after a few hundred years though Mars has enough of a population that they end up needing new resources (obviously we need some story as to how they expand this quickly, I blame genetic engineering and Hoxar Matos the dictator-general of Mars who commands a billion test tube babies be born and raised by robots in the underground Martian nursery creches).
The model for grabby aliens is that Mars must find somewhere else to expand as they are part of the human civilization - but given human civilization it seems more like splitting the civilization and infighting to get more resources would be the most likely outcome.
Is it, though? Grant me whatever assumptions I like and I can put tight bounds on anything - as long as it's unfalsifiable, at least.
Neither of those positions is irrational, except maybe the first (maybe), but there's certainly scenarios where it would be your only choice.
...given all of that is due to the risk of aggression from the Soviets, and I believe NATO may have disarmed themselves unilaterally if they didn’t see the SU/WP as a military threat (regardless of ideological threats) - what was making the SU so concerned about NATO military threats? Did the SU still have expansionist designs... or did they actually believe NATO still wanted to liberate/claim Poland long after the 1960s?
MAD is a formal (i.e. mathematical) model. It is 100%, unequivocally rational. The problem is that this rational process leads to outcomes you and I dislike.
These "bad outcomes" are value judgements. That is, MAD's outocmes don't align with our values. Therefore, the problem with mad (on which we agree!) is based in something extra-rational: values.
Again: you and I agree there is a problem with MAD. Where you are wrong is that the problem is not "MAD is irrational". The problem is "MAD's logical conclusions run afoul of our values".
Of course, this is all just making guesses about technology way beyond our current comprehension. Maybe universe-destroying bombs come up rather early in technology on this scale. Who knows.
So much so that parts of Human Male's anatomy seems to be purposely driven for combat and survival. Things like larger muscles, thickness of skull, thickness of neck. Also, societies seem to come together and cooperate, hunker down, in war and conflict. Also seems to me to have some genetic component to that social behaviour.
Only about 50% of men have reproduced through out human history. Raiding a neighbouring village, killing the man, and taking the best women for wives would be a rational though unethical behaviour. Its exactly what the Vikings did.
In fact, there's a growing concern that large and growing percentage of men, currently unattractive to females (internet incels) will lead to radicalization and possibly conflict in the west. As those man try to better their odds of reproduction. Currently they are genetic rejects.
If the base requirement for life is liquid water, then it is a generic property that you find it in most moons and dwarf planets, usually driven by pressure and geothermal or tidal energy. If the under layer is rock instead of ice you could have thermal vent economies like we have in ocean rifts.
In comparison the Earth is a really dry place, the most special thing about it is that the plants support an oxygen economy that might not be necessary for complex life but it sure helps.
Any species that masters interstellar travel is going to know how to cut up something like Ceres or Pluto into hundreds of thousands of miles of shopping malls and apartment buildings and might not find inner solar system bodies that interesting. In fact they might not even have an off-the-shelf landing vehicle that would work on Earth and might spend a few years developing one.
Even a modest increase in Earths gravity, or significantly denser atmosphere would make reaching orbit unviable. I also don’t see how life evolving in liquid voids on outer planet moons, or similar environments, could develop much beyond simple invertebrates or equivalent.
I’m really despairing that spacefaring civilisations are at all likely. Life yes, I think it’s likely to be reasonably common at the galactic level. Intelligent life, sure. But I think we’re fantastically lucky to be in the situation we find ourselves. I know statistics says we’re supposed to most likely be typical, but random chance doesn’t care about how many possibilities didn’t show up. If a lottery has a winner, that ticket won just as much no matter if there were 10 losers or a billion of them.
Thus "the Lord has many mansions" and one would expect creativity to be generic in the universe.
Maybe the materials science would still be a deal breaker, but in theory it would be easier to build than a space elevator.
I can't help but think SpaceX and the rest of us are missing out by targeting places like the moon or mars when there are so many asteroids out there. Maybe some of them could be used as a space station or slowly morphed into a spaceship with higher mass than we could ever launch? (like 1036 ganymed)
I guess that the reason globe-spanning empires and trading companies appeared from about 1600 on was in fact because sailing ships had reduced the travel time enough to allow a cohesive network with some centralized control. Previously, with slower communications, they tended to lose control of the extremities and devolve to looser associations (because the lag was excessive, on the scale of a human life)
Anyway, its commonly been theorized that waging war across unimaginable interstellar distances is unlikely or even impossible. Hard enough to seed another system with a spore, much less export capability to wage war.
Interstellar bombardment of a single planet seems possible but if you had asteroid mining in one solar system or a multi solar system I think the targeting problem is intractable.
I tend to think that we're just 1 or 2 discoveries away from a very different view of the universe. The low hanging fruit being stuff like: detecting neutrinos cheaply, having a better understanding of quantum computing/entanglement/etc, knowing how the extra dimensions at subatomic levels work (and how a dimension might be lost/gained or open up sub-universes within black holes), understanding how the electromagnetic/strong/weak/gravity forces converge at high energies and how to modulate one or more with the others, etc.
If we're able to take all that stuff for granted, then the answer is probably that aliens communicate over some kind of encrypted quantum communication channel over something like neutrinos that is very hard to detect. They probably live around energy sources like magnetars and black holes and such so there's no way we'll ever see them against that glare. And their brains have almost certainly been uploaded to a metaverse that we have difficulty imagining, where our whole planet's computation would fit on a microscopic chip of theirs.
I guess what I'm saying is, we might be more likely to find aliens through an altered state than out in space. They're probably here right now waiting for a knock on the door, once we know which door we're looking for. So yes, their superintelligent technology that's indistinguishable from magic to us might as well be religion at this point.
The pattern that I find distasteful in this kind of thinking is deducing universal rules of complex behavior from a few first principles. A good analogue of this is the Cold War era infatuation with game theory, as it would pertain to nuclear war, or many simple models of economics.
We know that in reality, human beings are quite complex, and their actual behavior bears no relationship to such "first principles" models, no matter how persuasive their authors find them. Yet we have the advantage of being human and understanding our own thinking. The idea that we could be more successful making such inferences from first principles about non-human, hyperintelligent entities, when we can't do it for ourselves, is laughable.
Even such basic questions like "does life always arise from Darwinian evolution" or "what is the physical basis of consciousness" are open. So in a strong sense we know nothing at all about the nature of intelligent life in the Universe, except that it happened at least once, and caused everyone no end of trouble.
Till and until are both old in the language and are interchangeable . . .
First recorded before 900; Middle English; Old English (north) til “to,” from Old Norse til “to,” . . .
Many people assume that till is a misshapen abbreviation of until... However, till is not a shortening of until. It actually predates the longer word.
The above paragraph is from Merriam-Webster: