This is why I’m getting lost in this thread. Is that what @Mijin is claiming, or you, or just sarcasm?
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The universe is super duper old. On stellar timescales, biological evolution happens in the blink of an eye. On evulotionary timescales, technological development happens in the blink of an eye.
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It would seem unreasonable that it was totally impossible for life to develop anywhere in the universe until right when life evolved on Earth. If life is common, we would expect that stars that formed billions of years before ours, with planets billions of years older than Earth, could have given rise to life long before Earth’s crust cooled enough for life to develop here.
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If intelligence is common, then we would expect it to arise on other planets that have life. Since those planets could be billions of years older than Earth, and it took only a few hundred million years for life to go from “multicellular” to “intelligent”, then intelligent life could have arisen on them billions or hundreds of millions of years ago.
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Hundreds of millions of years is plenty of time to conquer the galaxy. So either alien life (or at least intelligent alien life) is so uncommon that we are the first to arise in the observable universe, or there is some kind of horrible catastrophe awaiting us that destroys EVERY civilization that gets to our level before they can spread exponentially into space.
I see universe and galaxy being mentioned almost interchangeably, not necessarily in this thread, but often enough. I think it’s important to keep them apart when discussing the Fermi Paradox.
If only 1 in a billion galaxies have an advanced civilization, that translates to ~1 billion advanced civilizations in the universe (using the Hubble estimate of 100 billion galaxies).
Our galaxy could have no advanced civilizations (I’m not counting humans as advanced, even though I built a pretty high-tech Pine-box derby car in Cub scouts) and that would make us very typical in a universe containing a billion advanced civilizations.
But, I believe we’re all on the same page in considering the Fermi Paradox realistically applies only to the Milky Way galaxy, unless you believe we could detect life in a different galaxy, or intergalactic travel is possible.
Exactly. I don’t think there’s anything improbable about no other intelligent beings existing in the Milky Way galaxy with the capability to be seeding other stars or anything else we might be able to detect. And again, within that short period of time we would be capable of noticing them, it’s not necessary for them to go unnoticed for millions of years into the future in order to resolve any paradox, only that they are not here now.
I don’t see how. It didn’t stop oumuamua. It’s a speed limit, not a road closed sign.
Great, and since no one is saying that, we can move on.
It’s more that no one has given any good reason as to why that is not where we could be in a million years.
Have you met exponential growth?
Not really. It’s not millions of years to get stuff from the next system over. Thousands or so, maybe, but not millions. And you wouldn’t wait until stuff stops coming back to send out the next wave, you’d be sending them out all over.
It seems kinda silly that if you buy a fish on the coast of Ireland in the grocery store, it may have come out of the water a mile away, but it passed through China on its way to your table, but that’s how it is. That doesn’t mean that you have to wait a month for the fish to make the trip, the fish that you are eating now started its journey long ago.
Is what you just claimed realistic? Not really, but it’s also not what anyone else claimed.
It’s a fine tuning argument on the probability. If I claim that the chances of something like us popping up is less than one in a quadrillion, then I don’t need an upper bound to that number. It could be one in a quintillion, or it could be one in a Graham’s number.
OTOH, you have to limit both your lower and upper bounds on your probability. You need to make sure that it’s improbable enough that we don’t see anyone, but probable enough that there is something else out there.
Which, in your opinion, is more likely: That the probability of life like us is extremely rare, to where you would only expect to see less than one example in a particular patch of causally connected space, or that it is balanced to give the number that you want it to be?
You also bring up the unique argument. Now, as I have said, no one has given any sort of compelling reason as to why we will not be making ourselves very visible to anyone in the galaxy in relatively short order. So, either we are the only species out of a great many that would do so, or we are simply the only species, period.
So, if you think that there are a great many species out there, then why are we unique?
But we can clearly see that they didn’t.
Yes, you have given reasons as to why some may not. You have not given reasons why none ever can or will.
You can’t get away with saying maybe this or maybe that. You have to explain why no alien intelligence, out of the “great many” that you claim are out there, will ever make any sort of mega structure visible from far away (keep in mind that if Tabby’s star had been a megastructure, we would have seen it from nearly 1500 ly away), or ever leave their solar system.
Not why some won’t, or most, or even nearly all. Every single one.
Yes, but as my side isn’t arguing for a need for FTL, and the only one bringing it up at all is your side, that’s pretty much the definition of a strawman.
So, why didn’t they evolve a hundred million years earlier, so that they are evolved to where we can see them?
As I see there is little reason to continue any disucssion with you, so long as you continue to misrepresent my position so ridiculously, that’s fine.
On a very last note to you:
No, I am making the exact opposite point, and that you are unable to parse that, along with your attempts at belittling, means that your posts hold absolutely no interest to me going further.
Depending on whether you count us, between 0 and 1.
That’s why I’m so excited about the Enceladus mission, and would like to see a sub on Europa. We’ll get a lot more data. If they are sterile, that’s a data point. If they have prokaryotic single celled life, that’s a data point, and if they have dolphins and whales, that’s a data point.
I lean heavily on the former, but that’s just speculation until there’s some data.
Yes, but it did happen pretty early on in the history of the Earth, indicating that it’s probably not all that hard.
It took a couple billion years for life on Earth to make that leap, which is why I believe that it is a pretty big filter.
Even after that, it took another billion and a half to start making multicellular life.
Starts to pick up from there, with complexity rising quickly.
Like I said, it’ll be interesting to see some data points. Hard to give a good probability when your sample size is 1.
Why such a fine tuned number?
Once again, you are fine tuning to get the number you want. I think the number is even smaller, 0. (or 1, if you count us).
Given all that, then we still get left with the fact that humanity is unique. Why are we so unique?
It really only takes one.
Why? If I send a probe out to Ceres, then I get stuff back. If I send one out to Triton, then I get stuff back a little later. If I send one out to 486958 Arrokoth then I start getting stuff back a bit later than that.
I just keep sending them out, or even just having them replicate themselves, and they just set up supply lines that just keep bringing me stuff.
Two points on that, first, we didn’t send out a probe to wait ten thousand years to get anything back. We sent out a probe that will return things in a few years, and while it is at it, it will send out a couple more probes in that direction to continue to grow our supply lines. And second, who’s to say that we will not be the ones reaping those benefits in ten thousand years?
Neither do I, neither does anyone on this side of the debate. The only ones bringing up sci-fi and fantasy are the ones on your side.
So, you believe in a fine tuned universe that just happens to have exactly the chances of AC that means that they are out there, but not enough that we can see them.
That’s fine, I just find it very unlikely.
That’s another possibility, one that hopefully we will have data on within the next couple decades.
Once again, fine tuning.
That’s another data point that hopefully we will have in the next few years.
Where is the next Goldilocks planet over, and how would we detect it?
And as much as some seem to think that the former is dismal, I find the latter to be much more so.
Given an infinite universe, then there are infinite intelligences out there, and each one of them is looking up, wondering where everyone is.
The question is whether any of them are close enough to matter. My contention is that there probably isn’t another intelligent life within trillions of light years.
I’d count humans as advanced, or at least, more advanced than anything else for a trillion light years around, which makes our galaxy very special.
Eh, I’d limit it to the local group. If there were a K3 civ in Andromeda, it’d be pretty obvious. And if we wanted to go to Andromeda, the journey’s only going to take a few tens to hundreds of millions of years.
We have 1 data point of life in our galaxy—the Earth’s biosphere. We have a few data points of intelligence in our galaxy—orcas, octopuses and my cat (maybe a few more, but we all evolved from the same common ancestor, so let’s keep that data point at 1). We have 1 data point for a tech-savvy intelligence in the galaxy—us. That could all change tomorrow with an announcement on Fox TV (unless they think “Extraterrestrial Life Discovered!” isn’t important enough to bump the Simpsons). But, so far, that’s all we got.
In my mind, we can rule out the two extremes. 1) A huge number of intelligence-bearing planets in the MW. Why? Because at least some would have gone tech-savvy expansionists and launched SR probes reaching us by now. 2) 0 intelligence-bearing planets in the MW. Why? Because I’m looking at my cat and I don’t think he’s an illusion (though I wish the little bugger was).
I didn’t realize we were on sides. If so, I’m on the side of Baby Bear of Goldilocks fame. My galaxy is “just right” with a modest number intelligent lifeforms in it. Some of you appear to be Papa Bear with a “too hot” galaxy oozing with intelligence-bearing planets, while others appear to be Mama Bear with a “too cold” galaxy of 1 intelligence-bearing planets.
Why do you believe 1 intelligence-bearing planet in the galaxy is more likely or credible than a few intelligence-bearing planets? Is it because you believe abiogenesis is that rare, or some other reason?
I’ll sell you a ticket to Andromeda, just wait at the bus stop for 5 billion years and you’ll get there
Because if there were a few intelligence bearing planets, then you’d have to explain why there are a few intelligence bearing planets today, but there were none one million years ago, even though on a stellar scale a million years ago the galaxy was basically identical.
Because if there WERE intelligence bearing planets a million years ago, or 65 million years ago, or 200 million years ago, or 1 billion years ago - all timeframes during which our galaxy wasn’t all that different from now - then they’d have had plenty of time to colonize every rock in the galaxy.
I think if a civilization was smart enought to go K3, they’d be smart enough to cloak it.
That assumes they would want to colonize every rock in the galaxy. My position which I expanded on up-thread, is that there are valid reasons why they would not.
You are assuming that a K3 civ can break the laws of themodynamics just because they’re smarter than us. It is entirely possible that these laws aren’t breakable.
Why do you think cloaking a k3 galaxy is a more insurmountable task than building it in the first place? And besides, there’s good reason to cloak—to hide from their supercluster’s cloaked K4 civ. Trust me, you don’t want to piss those guys off!
Of course, I believe anything beyond K1 is pure fantasy.
There are no valid reasons not to colonize every rock. I’m not saying 21st century humans are going to do it, but in a million years, our descendants (including artificial ones) will either be extinct or absolutely everywhere.
Saying otherwise is like looking at Earth when the only milticellular life was Grypania spiralis and saying “multicellular life can never leave the muddy shallows! There are valid reasons to stay!”
You are right, there may be humans that stay on Earth, or in the Solar System. But unless something actively restrains us or we are all dead, at least SOME of us would go expand. Especially on the time scale of millions of years.
Again, if a group of aliens likes living around their home star so much that it is a super rare event for some tiny splinter group to leave and go colonize a new solar system - once in ten thousand years - then the whole galaxy would be full in just a few million years. And there have been billions of years for life to show up.
Building a K3 civilization is a monumental task. It would require you to fly out to asteroids and hack them up to make solar panels, then surround every star completely with them. It would take billions of years to complete the job. It’s a big job, but it’s also not complicated in the least. It just requires lots and lots and lots and lots… and lots and lots and lots of labor and resources.
“Cloaking” is nonsense magic with no basis in physics.
It’s like asking “why do you think putting a man on Pluto is more achievable than learning to cast Avedra Kadabra like in Harry Potter?”. One is really really hard, a monumental feat of engineering. The other is a childern’s story.
We will have to disagree to agree.
…or visa versa.
The Fermi conundrum has two broad classes of solutions; the first general class of solutions is concerned with physical phenomena, such as the difficulty of interstellar travel, the abundance (or otherwise) of suitable planets and the likelihood of abiogenesis.
The second general class of solutions is psycho-social; this includes the tendency for a species to stay at home and develop their own planet or system exclusively, or the tendency for a species to become extinct before expanding into the greater galaxy.
I think that solutions in the first class are likely to be universal, and apply to all potential life-bearing worlds; but the solutions in the second class are parochial, and each individual species or civilisation will be more-or-less unique in its psychological characteristics. So I would hesitate to generalise about alien behaviour in any way, until and unless we actually meet them.