# Is the universe old or young? **URL:** \ **Category:** Great Debates\ **Created:** [April 23, 2022, 10:17pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334 "2022-04-23T22:17:54Z")\ **Posts on this page:** 20\ **Page:** 13
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 3, 2022, 4:15pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/241 "2022-05-03T16:15:32Z")
> [@Babale](#): > > Yeah, there’s nothing mysterious about “life and/or intelligence is so rare that no advanced alien civilizations exist anywhere in the observable universe” This is why I’m getting lost in this thread. Is that what @Mijin is claiming, or you, or just sarcasm? ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 3, 2022, 4:29pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/242 "2022-05-03T16:29:09Z")
> [@TriPolar](#): > > This is why I’m getting lost in this thread. Is that what @Mijin is claiming, or you, or just sarcasm?. 1. 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. 2. 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. 3. 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. 4. 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. ---
**Author:** ![Tibby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tibby/32/17030_2.png) [@Tibby](https://boards.straightdope.com/u/Tibby)\ **Post date:** [May 3, 2022, 4:57pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/243 "2022-05-03T16:57:10Z")
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. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 3, 2022, 5:54pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/244 "2022-05-03T17:54:36Z")
> [@Tibby](#): > > 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. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [May 3, 2022, 6:36pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/245 "2022-05-03T18:36:20Z")
> [@wolfpup](#): > > The speed of light is such a physical constraint. I don’t see how. It didn’t stop oumuamua. It’s a speed limit, not a road closed sign. > [@wolfpup](#): > > I don’t doubt that science and technology will discover and produce mind-boggling wonders in the future, but that’s not the same as saying that one of the most fundamental foundations of physics is completely wrong. Great, and since no one is saying that, we can move on. > [@wolfpup](#): > > I guess it’s just frustrating that this concept is so frequently presented as a self-evident truth about the behaviours of sufficiently advanced civilizations. 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. > [@wolfpup](#): > > if we’re talking about the quest for resources I’d speculate it’s unlikely that the resources of an entire planetary system (most of which is likely to be resource-rich yet uninhabitable) would be exhausted in any foreseeable timeframe. And you were talking about essentially mining operations for resources. Have you met exponential growth? > [@wolfpup](#): > > Doing that on an interstellar scale would require resource planning with millions of years of lead time. 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. > [@wolfpup](#): > > Is that realistic for any conceivable civilization? Is what you just claimed realistic? Not really, but it’s also not what anyone else claimed. > [@wolfpup](#): > > The question is this. What is more likely – that we are absolutely unique in the entire galaxy of millions or billions of potentially life-bearing planets, or that we’re just typical, just one among a great many? 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? > [@wolfpup](#): > > I really don’t know, but the same factors could have affected any successful dominant species. But we can clearly see that they didn’t. > [@wolfpup](#): > > Many possible reasons have already been given, all quite plausible. 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. > [@wolfpup](#): > > It’s not a strawman, it’s a physical reality, and showing it to be wrong requires dismantling the very foundations of physics. 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. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [May 3, 2022, 6:41pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/246 "2022-05-03T18:41:16Z")
> [@TriPolar](#): > > Again I will point out, if any did evolve they have not gotten to where we can see them yet or they are hiding. So, why didn’t they evolve a hundred million years earlier, so that they _are_ evolved to where we can see them? ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [May 3, 2022, 6:50pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/247 "2022-05-03T18:50:56Z")
> [@TriPolar](#): > > Are you making the argument that we haven’t encountered intelligent aliens yet because they are spreading self-replicating habitats through the universe? 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: > [@TriPolar](#): > > Are you making the argument that we haven’t encountered intelligent aliens yet because they are spreading self-replicating habitats through the universe? 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. ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [May 3, 2022, 7:14pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/248 "2022-05-03T19:14:51Z")
> [@Tibby](#): > > How many advanced civilizations do you believe inhabit our galaxy? Depending on whether you count us, between 0 and 1. > [@Tibby](#): > > I said I believe life may be common in our galaxy, but I didn’t mean so common as to be present in any star system in our general (observable) vicinity. 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. > [@Tibby](#): > > Abiogenesis, as far as we know, occurred just _once_ on our planet. Sure, once it occurred, life evolved, branched, flourished and filled every habitable environment on Earth. Yes, but it did happen pretty early on in the history of the Earth, indicating that it’s probably not all that hard. > [@Tibby](#): > > I don’t believe the transition from simple to complex life is a great filter 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. > [@Tibby](#): > > IMO, the big filter is abiogenesis. [Abiogenesis is improbable](https://www.cs.unc.edu/~plaisted/ce/abiogenesis.html). Like I said, it’ll be interesting to see some data points. Hard to give a good probability when your sample size is 1. > [@Tibby](#): > > I personally believe the probability of abiogenesis, even on planetary scales, is extremely rare. When I say I believe simple life is “common” in the galaxy, I’m thinking downwards of perhaps 10,000 cases in a galaxy with 1011 Sun-like stars, like the Milky Way. Why such a fine tuned number? > [@Tibby](#): > > I don’t believe accounting for _“every alien civilization”_ is a large number at all. I think the number is quite small (~ a handful). 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). > [@Tibby](#): > > In that perspective, positing _“all advanced civilizations are likely to have evolved past the archaic human mindset of unlimited expansion and venturing beyond the controllable horizon”_ is not a tall order, because there’ are not many (or any) in our galaxy to buck the enlightened trend. Given all that, then we still get left with the fact that humanity is unique. Why are we so unique? > [@Tibby](#): > > Yes, probably a few trend buckers, and we should see evidence of their existence. A handful? Probably not. It really only takes _one_. > [@Tibby](#): > > Back to the question of why an AC would send self-replicating probes to far reaches of the galaxy when it would take a minimum of tens of thousands of years to reap any benefit, I still don’t believe they would bother. 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. > [@Tibby](#): > > Even we colonizing, expansion-hungry humans don’t plan that far into the future. A few generations into the future, sure. _Let’s do something nice for our grandkids._ Thousands of generations? _Humbug, we’ll leave that problem for our distant descendants._ 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? > [@Tibby](#): > > So, I don’t believe we’re dealing with a Star Wars galaxy, with spaceships manned with a plethora of various alien species zipping all around interstellar space. 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. > [@Tibby](#): > > I think we’re dealing with a few ACs, if we’re lucky. And, I don’t believe it’s unreasonable to believe all of them have eschewed the desire to expand into far-away places beyond manageable central control. 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. > [@Tibby](#): > > Nutshell: Abiogenesis is the big filter. It’s extremely rare. That’s another possibility, one that hopefully we will have data on within the next couple decades. > [@Tibby](#): > > The few advanced civilizations that have likely emerged in our galaxy have evolved past the archaic notion of expanding into every nook and cranny. That’s why we don’t see evidence of life beyond Earth. Once again, fine tuning. > [@Tibby](#): > > then we would expect to see evidence of life on the next Goldilocks planet over. But, so far, we don’t. 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? ---
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [May 3, 2022, 7:46pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/249 "2022-05-03T19:46:03Z")
> [@Babale](#): > > 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. And as much as some seem to think that the former is dismal, I find the latter to be much more so. > [@Tibby](#): > > 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). 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. > [@Tibby](#): > > 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. 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. > [@Tibby](#): > > 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. 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. ---
**Author:** ![Tibby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tibby/32/17030_2.png) [@Tibby](https://boards.straightdope.com/u/Tibby)\ **Post date:** [May 3, 2022, 8:25pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/250 "2022-05-03T20:25:50Z")
> [@k9bfriender](#): > > Depending on whether you count us, between 0 and 1. 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? ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 3, 2022, 8:33pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/251 "2022-05-03T20:33:36Z")
> [@k9bfriender](#): > > 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. I’ll sell you a ticket to Andromeda, just wait at the bus stop for 5 billion years and you’ll get there ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 3, 2022, 8:37pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/252 "2022-05-03T20:37:43Z")
> [@Tibby](#): > > 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? 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. ---
**Author:** ![Tibby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tibby/32/17030_2.png) [@Tibby](https://boards.straightdope.com/u/Tibby)\ **Post date:** [May 3, 2022, 8:44pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/253 "2022-05-03T20:44:36Z")
> [@k9bfriender](#): > > If there were a K3 civ in Andromeda, it’d be pretty obvious. I think if a civilization was smart enought to go K3, they’d be smart enough to cloak it. ---
**Author:** ![Tibby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tibby/32/17030_2.png) [@Tibby](https://boards.straightdope.com/u/Tibby)\ **Post date:** [May 3, 2022, 8:54pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/254 "2022-05-03T20:54:03Z")
> [@Babale](#): > > 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. 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. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 3, 2022, 9:08pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/255 "2022-05-03T21:08:39Z")
> [@Tibby](#): > > > [@k9bfriender](#): > > > > If there were a K3 civ in Andromeda, it’d be pretty obvious. > > I think if a civilization was smart enought to go K3, they’d be smart enough to cloak it. 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. ---
**Author:** ![Tibby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tibby/32/17030_2.png) [@Tibby](https://boards.straightdope.com/u/Tibby)\ **Post date:** [May 3, 2022, 9:14pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/256 "2022-05-03T21:14:55Z")
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. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 3, 2022, 9:15pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/257 "2022-05-03T21:15:04Z")
> [@Tibby](#): > > 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. 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. ---
**Author:** ![Babale](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/babale/32/15666_2.png) [@Babale](https://boards.straightdope.com/u/Babale)\ **Post date:** [May 3, 2022, 9:18pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/258 "2022-05-03T21:18:26Z")
> [@Tibby](#): > > Why do you think cloaking a k3 galaxy is a more insurmountable task than building it in the first place? 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. ---
**Author:** ![Tibby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tibby/32/17030_2.png) [@Tibby](https://boards.straightdope.com/u/Tibby)\ **Post date:** [May 3, 2022, 9:18pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/259 "2022-05-03T21:18:46Z")
> [@Babale](#): > > There are no valid reasons not to colonize every rock. We will have to disagree to agree. …or visa versa. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [May 3, 2022, 9:19pm UTC](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334/260 "2022-05-03T21:19:19Z")
> [@Tibby](#): > > My position which I expanded on up-thread, is that there are valid reasons why they would not. 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. [Previous page](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334.md?page=12) [Next page](https://boards.straightdope.com/t/is-the-universe-old-or-young/963334.md?page=14)