You are thinking on too short a timescale. A Dyson swarm around a red dwarf star might be dynamically unstable, but it would only take a fraction of the available processing power in such a structure to maintain the swarm using station keeping; this situation could last for trillions of years, until the star itself dies.
The light-speed delays within such a structure could favour a very slow existence for such an entity - if it takes twenty minutes for the entire structure to formulate a single, coherent thought, that might mean that a trillion years could pass on a much shorter subjective timescale.
Since we don’t see any evidence for such structures, I think some other factors need to be accounted for. All suitably advanced civilisations will want and need to plan for the deep future - if they are not building trillion-year Dyson swarms, they must have better ideas. Or they don’t exist, which is entirely possible.
Yeah and I thought of a simpler way to phrase my previous point:
Deep time can only be a problem for the Fermi paradox, it can’t be the solution,
Because either species can reach across deep time (or leave relics or whatever), or they can’t.
If they can, then that is yet more civilizations that could have left visible evidence for us to see, but, for unknown reasons, no such evidence has been verified.
If they can’t then the situation is exactly the same as if there was not deep time. Why do we not see evidence of ETs in our time window?
This (subsequent timescale correction noted) is the kind of thing I have been alluding to; it’s one thing to be aware that materials inevitably degrade in deep time, but it is quite another thing to have a solution or workaround for that. Repair is an option, but requires power sources, which degrade, and are impossible to refuel mid-journey.
To paraphrase Terry Pratchett, perhaps for the same reason that people in Trafalgar Square can’t see England. Maybe we’re it.
Not a new idea, but what if panspermia is it - the spread of ‘probes’ is actually just the seeding of simple life or its precursors - produced in vast number by a planet teeeming with life, sufficiently so that by sheer weight of numbers, a tiny few last long enough to make it across the void inside rocks or chunks of ice, to a different system, not even deliberately.
Not all materials will degrade significantly within this timeframe though, so there is no fundamental physics that prohibits such a probe being built. So, once again, you’re talking about engineering challenges, which are largely irrelevant to the Fermi paradox.
Sure, that’s a possibility.
It’s not a solution to the Fermi paradox (and also, I’m not sure how it relates to the post you’re responding to), but yeah, in principle life could be seeded to many star systems from a single origin. There are earthly bacteria that seem to be able to survive space in a “just add water” state. And, encased in rock, could hypothetically survive re-entry.
Because life in the universe is simply not common enough for us to continuously be contacted by aliens.
I think the deep time thing is an explanation that life can be out there, and even somewhat common, but not common enough to overlap with us both temporally and spatially. How long has it been since we’ve had the technology to detect, and the ability to reliably record an alien visit (probe or otherwise)? Maybe 100 years?
Sure, maybe a probe visited 1000 years ago, and some monks wrote it down, but now we’re into von Däniken territory. Maybe a probe is flying through our solar system right now, but it’s too dark and radio silent, so we just don’t know. Maybe there was a civilization that broadcast radio waves for thousands of years, but the signals all reached earth 50 million years ago?
So in order to ignore deep time we have to say there are so many alien civilizations, or at least one of them is so large and active, that they are sending probes, radio waves, light, or gravity waves to us essentially continuously, so we don’t miss them.
I didn’t say ignore deep time. The point is, it doesn’t help in terms of the Fermi paradox, it’s just more civilizations that could leave something for us to see. If we’re positing that life is so rare that there is only one example of it in our galaxy in the last billion years then that is the solution being suggested for the Fermi paradox.
Not really no. Any civilization just needs to do anything that is detectable to us now.
That could be a megastructure, including Dyson spheres, but also megastructures that we couldn’t understand the function of. It could be a legacy of probes around all stars. Or beacons using stellar radiation to broadcast messages for as long as the star is around. For a very advanced civilization it could be some kind of modification to stars or the galaxy itself.
Species don’t need to be contemporaneous, and they don’t need to have specifically sent a message to humans.
Mechanical parts seize; electronics get fried; both require refining and manufacturing infrastructure to boot up their production. A self-replicating probe would need to be able to manufacture copies of itself with very little external support, making its own parts from common chemicals.
We have an example of self-replicators that already do that right here. Where is everybody? We’re here - we just forgot we’re ‘everybody’.
Interstellar probes with the objective of spreading across the galaxy would seem to need mission objectives comprising:
Replicate - make more probles
Spread - make the new probes go places
Adapt - be able to use variations in raw materials; be able to exploit different energy resources
and
Do something probe-y - build something to transmit information home, maybe.
Small, adaptable things will accidentally evolve - through adaptive mechanisms built into them, or through mutation caused by damage; functions can be lost or added.
If they lose the function for objective 1, they die out
If they lose function 2, they don’t spread
If they lose function 3, they will be outcompeted by their siblings
If they lose function 4… they lose a burden - they become simpler to make, potentially smaller, lighter, more durable and less expensive in terms of resource demand and more competitive for those resources than their siblings that are still trying to build transmitters or whatever. It’s an advantage for self-replicating adaptive probes to stop doing the ‘probe’ objective.
This is beyond painful at this point. You surely must know by now what I’m about to say: Engineering problems are irrelevant to the Fermi paradox
We are talking about aliens that most likely will have spent, conservatively, millions of times longer on space technology than the mere decades that humans have so far.
What engineering blocks that humans currently have can we be confident will still be blocks over that timeframe? The answer is: Only those things that are fundamental limits of physics. And even then, probably some of the things that we think of as fundamental limits are actually not with a fuller understanding, but we need to at least begin from that set of things thought to be impossible in principle.
There is no fundamental physical reason that we are aware of that a machine lasting millions or even billions of years could not be constructed.
I hope your next post directly responds to this point.
Not just yet another repeat of your skepticism, which is not an argument.
But we’d have to actually see examples of such limits, not just assume that they must be there.
The half life of Thorium is ~14 billion years, unless we are talking about timescales in that range, it is something that can be worked around.
Maybe by some, but that’s not an argument that anyone is making in this thread, so I don’t know why you would try to invoke it here. There are actually well understood laws of physics that explain why we almost certainly cannot travel faster than C. The “can’t travel faster than 30mph”, which was not a position held by many at all, and was not based on anything like robust science, just individual incredulity.
Then where did they go? Are we saying that there is a limit to how long a civ can last? What reasoning is this based on?
I don’t think that there is anything that gives any evidence to these suppositions.
I have a slightly different thought experiment. You have a continent sized plain of grass. Every few years, you drop a small group of rabbits in a random location. What are the odds that two of these groups encounter eachother.
Sure, some will die off, some will stabilize their population, but unless you can explain why all of them would, then you would expect that in a few hundred or thousand years, the continent will be covered with rabbits.
They also give plenty of time for the improbable to happen. It seems as though there needs to be an explanation as to why it is impossible, not just improbable, that a civ would have expanded out into the galaxy and beyond.
Only if the civ that created them left them to fend for themselves. Why would they do that? In fact, why would they not expand out, and make a swarm around nearby stars, who then expand to stars further out?
Energy collection to run their civilization, or the computers that they have moved themselves into.
Or just that they don’t all die off, and instead expands. It only takes one.
They wouldn’t need to be all that adaptable for that. We know what elements exist and are useful, we know what power sources exist and are useful. That a system has a slightly different chemical composition or different primary wavelength of solar output doesn’t mean that it needs to evolve to those conditions, but rather to use a simple table to determine the best way to use those resources.
I see probes not as pure exploration, but as colonization. More of a Bracewell Probe than Voyager.
Whether it be uploaded minds, or genetic information with the capability of building bodies at the destination, the point would not be to to transmit information home, but rather to make this star system their new home.
Mutation is a part of life, and it has been since the beginning, otherwise, we’d still be basic cellular structures turning carbon dioxide into methane around sea vents or something.
We can design better. We can build in enough redundancy that mutation becomes improbable enough to not be a concern.
“Probes” can also be actual civilizations. If we create a self sustaining colony on an asteroid, then that will continue to grow and replicate. At some point, either we will have grown out so far into and past the Oort cloud that we see that we are actually closer to another star than we are to Sol, and/or some colonies decide that this system is getting crowded, and head off to the next star.
There is a fair amount that we know.
What we don’t know is how much we don’t know.
It’s possible that we solve quantum gravity and have a Grand Unified Theory that explains everything in the next decade, but I doubt it. I suspect that there will always be one more layer to the laws of the universe to uncover.
Depends on what you mean. As it is, the human brain can’t really understand quantum science. At a certain point, analogies and descriptions no longer work, and the only way to “understand” is to do the math. We have long since passed the time when that math was done in our heads, or even on paper, and is now chugging away in supercomputers.
But that doesn’t mean that the human mind cannot still be used to solve problems in quantum science.
It doesn’t matter, it’s just a gut feeling. But I feel that setting up a shell of solar panels feels like an indirect and inefficient way to collect energy. I feel like a civilization able to push around the vast masses involved will have better ways to collect energy from their star.
So I’d be surprised if Dyson spheres prove to be a real tech, but it still makes sense to look for them of course.
Unless the engineering problems truly are insurmountable. Interstellar travel is just too difficult and too slow, and after a few million years of trying, space Elon Musk gives up. Each new alien civilization encounters the same engineering problems, perhaps ones we can’t even imagine, and stays stuck in their home system.
Maybe they are, and we just haven’t detected it. How long has it been since we could detect solar system scale megastructures half way across the galaxy? How much of the galaxy (and others) have we searched for them?
There is a large range between “one civilization” and “every rock in space has a civilization”. The frequency just has to be low enough that we don’t intersect.
I can’t remember, are you arguing that because nobody on this message board can come up with a satisfying solution to Fermi’s paradox, that means aliens are here, or are we just having a nerd debate about space aliens? (A very worthwhile pass time.)
I am not aware of any evidence that strongly suggests space aliens (or their probes or transmissions) have ever visited the earth (though there are lots of people that strongly suggest it, they lack evidence). However, that does not rule out that they exist somewhere, and something as simple as finding an exoplanet with an oxygen rich atmosphere may suggest life exists elsewhere in the universe.
I don’t think of it that way. Seems a pretty efficient way, actually. Assuming that we ever develop fusion, it will certainly take more engineering and maintenance than solar panels. Letting the star do the work for you on the first half of the energy generation seems pretty elegant to me.
We’ve already started building one. Every solar powered satellite is a component of a Dyson sphere. Assuming that we get off this rock and start building in space, that will only speed up.
Maybe we won’t block out 100% of the star’s light, but a pretty significant and detectable fraction of it, absolutely.
And if they aren’t doing Dyson swarms, then the next best thing is star lifting, and it seems that would be even easier to spot.
That’s possible.
I was just saying that it’s pointless, in the context of the Fermi paradox, to talk about so-and-so engineering problem. Yes we can speculate that there might be limits on what can be engineered that prevent aliens doing whatever, but the fact that something is incredibly difficult right now for us is completely irrelevant unless it’s literally against the laws of physics.
That’s possible.
No. I am just keen that people don’t misunderstand the Fermi paradox. This misunderstanding also seems to be a standard Dope pastime.
The Fermi paradox is not saying that there are no plausible explanations.
There are lots of plausible explanations.
The point is, we don’t have enough information yet to know which, if any, of the explanations proposed so far is correct. That shows a fascinating gap in our knowledge right now.
Maybe the gap in our knowledge is small – we learn a bit more about abiogenesis and find it’s so ridiculously unlikely that it’s only happened once in our galaxy.
Or maybe the gap is big, and there are many aspects of abiogenesis, evolution, sentience, civilization and interstellar transport and communication that form a very complex picture which we will very gradually lift the veil on.
Either way, it’s fascinating to speculate on these matters.
There are always unknowns, but there is nothing known to us to make it insurmountable.
If we can build a self sufficient space colony, then we can become interstellar, there really is nothing in between those two. And I see no reason why we cannot build a self sufficient space colony.
Why’s it always gotta be half way? What is the reason that there is such a fine tuning that there is one half way, but not a dozen closer?
If there was one within 1400 light years, we can see it. We saw Tabby’s Star, which was fairly close to what we would expect to see if someone was building a solar system scale megastructure.
I just don’t understand what it is that fine tunes it to that specific number.
You didn’t ask me, I know, but my position is that the two “acceptable” or at least, IMHO, probable, answers to the Fermi Paradox is either that all intelligent species encounter something that kills them off before they are able to expand into an interstellar civ, or that we are the first. I prefer the latter to the former, but I don’t know that we can rule it out.
I think that we will probably find life all over the place. We have good reason to believe that it existed on Mars, though that needs follow up to confirm, and I think that we will find it on Europa and probably a number of water moons.
Intelligent life, however, I think is a whole different story. There is nothing in evolution that favors intelligence, you can’t assume that it is inevitable that a life bearing world would develop it, even given unlimited time.
Great filters are either behind us or in front of us. Either there is no intelligent life, or we are it.
Well, let’s be precise here, because that line could be misleading.
There’s nothing in evolution that favors intelligence versus other survival traits i.e. there are plenty of organisms that are hella successful without needing higher cognitive function, or even a brain.
However, intelligence still belongs to the set of survival traits / strategies, so it is favored by evolution in that sense. And while humans are the only extant sentient species, there are plenty of species that have become more intelligent after they branched from our common ancestor; so it isn’t as though getting smarter was only an advantage for us and our direct ancestors.
Nothing outside of Homo became sentient of course, but given how quickly sentient species transform their world it seems that any sentient species is likely to find itself the first on its planet.
Or there are multiple significant filters below and above us that have a collective effect.
