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Salt Fish posted:I don't know about this number you have, but surely it must be the far side only? It's pretty hard to wiggle a meteor in between the earth and the near side. Just a quick google. quote:How often do meteoroids hit the Moon? originally appeared on Quora: the knowledge sharing network where compelling questions are answered by people with unique insights. And the side of the moon facing us is covered in craters you can look at yourself.
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Mar 1, 2021 21:54
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both of those things can be true if one side just gets hit more, though artificial structures might also have been composed of some polymer that breaks down with exposure to radiation, i suppose
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Mar 1, 2021 22:37
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Salt Fish posted:I don't know about this number you have, but surely it must be the far side only? It's pretty hard to wiggle a meteor in between the earth and the near side. Where are the meteors coming from that they won't impact the near side? The Earth's only blocking about 2 degrees of the FOV from the lunar surface at most.
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Mar 1, 2021 22:57
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The question is largely rhetorical but also can be directly applied to if we ever send probes out to explore other systems. Remember that Earth has had 5 mass extinctions in the time it's had multicellular life. Even the assumption that only stars the same relative age as ours could have the necessary heavy elements for organic chemistry leaves a billion year window before us where civilizations could have risen and fell and been swept away under the sediments of time. Australopithecus lived 3 million years ago. We've only had metalworking for less than 10,000 years. We're staring down the barrel of multiple Great Filter events. If any species ever escapes the Great Filter, they are far more likely to find us (or we find them) as a pre-technological ape or as the ruins of society that died a million years previous.
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Mar 1, 2021 23:43
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Well, perhaps the proof that intelligent extra terrestrial exist is that they never contact us. 
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Mar 2, 2021 03:29
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we should try searching the geological record for past civilizations
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Mar 2, 2021 08:19
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I feel like there's a group of people searching for Atlantis that would be all about this already.
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Mar 2, 2021 19:13
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The point is detecting extremely ancient civilizations would require purpose made testing and you wouldn't just stumble across stuff without applying a lot of actual experimental geophysics towards the problem.
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Mar 2, 2021 22:12
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I think we're living in the era where most people are still over-optimistic about the things science and technology can achieve in the future. Few centuries of exploring the Moon and nearby planets without any significant progress will surely make us apathetic towards space travel. If the physical laws are same throughout the universe, then this will probably happen with all alien civilizations.
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Mar 5, 2021 07:13
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Too bad there wasn’t a French person at that table with Fermi and the gang, they would have immediately proposed ennui as a solution to the paradox.
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Mar 5, 2021 16:31
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Chicken Butt posted:Too bad there wasn’t a French person at that table with Fermi and the gang, they would have immediately proposed ennui as a solution to the paradox. I'm not imagining an alien with a beret in a striped shirt, looking out of his spaceship window, smoking, slowly blinking and then sighing deeply.
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Mar 5, 2021 18:12
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Pope Hilarius II posted:I'm not imagining an alien with a beret in a striped shirt, looking out of his spaceship window, smoking, slowly blinking and then sighing deeply. Dear Diary, It is day 1,215,784. Le sigh.
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Mar 5, 2021 18:24
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I don't really understand why aging is a thing. Has aging evolved separately in multiple species or does it all stem from a single lineage of telomere having dumbasses? From the perspective of life being for a reduction of an entropy gradient I don't see a specific reason you'd need aging, but from the perspective of genetic drift and selection being good for survival I guess it makes sense as one possible solution. If there's a good reason aging exists then it could make sense that for all life there's an optimal life expectancy. Imagine if you could understand the reason for it to be any specific number. For example, what if the optimal life expectancy is comparable to the average duration between catastrophic events? We could guess that life spans shouldn't be orders of magnitude more or less than the the periods of stability that are normal for whatever organism we're talking about. Taking that further, maybe you could have some physical conditions that are typical for a planet that tell you that catastrophic events are likely to take place every 1,5, or 10 years, whatever, but very very unlikely to only happen every 100, or 1000 years, and this builds in a typical lifespan of life in the universe. Then you combine that typical lifespan with typical distances between systems being on the order of hundreds or thousands of light years, and an inescapable speed limit for travel, and you solve the fermi paradox. Notably for earth conditions are incredibly stable. Some areas had seasons where you can predict week by week the average temperature for decades at a time. You could really have 10,20,50 years with no major disruptions and this is on the same order as human lifespan. It would be interesting if intelligent life had lifespans of 10 years or 100 years and not 1 second, or 100,000,000 years anyway I'm pretty high.
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Mar 5, 2021 21:29
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Salt Fish posted:I don't really understand why aging is a thing. Has aging evolved separately in multiple species or does it all stem from a single lineage of telomere having dumbasses? well evolution only cares about fitness; if your genes are successfully passed on, nothing else matters it seems like no small part of aging-related degradation is a buildup in the body; just removing blood and replenishing it with saline improves the ability of elderly mice, for example that sort of thing is hard to evolve
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Mar 5, 2021 22:27
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Salt Fish posted:I don't really understand why aging is a thing. Has aging evolved separately in multiple species or does it all stem from a single lineage of telomere having dumbasses? Most large complex life on earth reproduces by making seeds/eggs/spores/whatever - tiny lumps of stuff that grow into a new organism. From a gene's perspective, it's not worth spending the resources to maintain one body indefinitely, when you're going to build a bunch of new ones anyway. (As for why life one Earth works like that. I've heard it suggested that it advantageous to reproduce that way, as it allows more radical changes in general body plan between generations - compared to, say, a creature that splits in half and grows into two creatures)
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Mar 6, 2021 01:30
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In addition: an organism that could live forever would over time be less adapted to its environment and lose competition to organisms that are better-adapted. I mean, imagine boomers living forever and doddering through each new wave of technology until they accidentally set themselves on fire or fry their brains.
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Mar 6, 2021 19:52
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That said there are organisms that display negligible senescence: they age and develop up until a point but then seem like they can just hang out forever until something eats them instead of eventually growing decrepit and dying from their internal systems breaking down.
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Mar 6, 2021 20:57
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was hanin
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Mar 7, 2021 05:42
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commando in tophat posted:I meant some bigger trash, like some storage building or whatever large that wouldn't be completely covered with dust (how much cm of dust was added to moon in 100m years? If they've taken everything with them then of course we will find nothing) According to geologists, you’d find a thin layer of complex hydrocarbons that were artificially created in the soil. The residue of plastic.
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Mar 7, 2021 06:35
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If there were a global civilization comparable to ours on the Earth, you'd see weird depositions of minerals from where they were originally mined out and redeposited in their population centers, probably--depending on how long ago the civilization was present. They might also have derelict probes around other bodies in our system or have mined asteroids in ways that would leave them unnaturally depleted of certain minerals or leave signs of excavation. Really, I think that humans strongly underestimate the likelihood that intelligence is rare in the universe because it confers no evolutionary advantage and seems likely to cause mass extinctions that would erase the intelligent species along with the rest, if our own behavior is any indication. It's like how algae will proliferate in a lake that receives fertilizer runoff, but then that algae disrupts the equilibrium of the lake that allows its own survival and ends up dying after it kills everything else in the lake.
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Mar 8, 2021 17:42
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I just found out that Mars had an oxygenation event similar to the Earth's, but about a billion years before ours and at a time when it had liquid water. The Earth's oxygenation event was caused by microbes, but of course there could be geologic processes that would cause such a thing to happen. Wouldn't it be wild if life on Earth were dumped here from Mars when it was more hospitable to life than the Earth, though? I also recently read that Venus had liquid water and was habitable as recently as 600 million years ago, which isn't really recent enough to overlap with multicellular life on the Earth, but wouldn't it be wild for complex life to be alive on both planets simultaneously?
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Mar 8, 2021 18:09
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I believe in aliensPentecoastal Elites posted:the virgin generation ship crewperson: our culture and institutional knowledge has degenerated to the point where we've all regressed to barbarians because somebody broke our library machine two thousand years ago. we're going to get to a planet that got baked by a gamma ray burst the day after we left and now it's just a dead ball of rock but nobody knows it. we're going to drift until our oxygen systems finally break down because the religion invented to pass that knowledge schismed and the two sides killed each other. this sucks and I hate it here. Le guin has a cool short story about a generational ship, gets into some of these issues
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Mar 9, 2021 19:58
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pointsofdata posted:I believe in aliens Oh yeah that reminds me, Children of Time features a generational ship that descends into barbarianism. Strong recommend on that book and its sequel.
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Mar 9, 2021 22:28
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Why does everyone assume that humans aren't special? Is that just one of the postulates Fermi requires for his paradox? I think we are genetic badasses that are the culmination of the survival of at least 5 mass extinction events over billions of years. That's pretty loving special.
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Mar 14, 2021 05:51
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ate poo poo on live tv posted:Why does everyone assume that humans aren't special? Is that just one of the postulates Fermi requires for his paradox? I think we are genetic badasses that are the culmination of the survival of at least 5 mass extinction events over billions of years. That's pretty loving special. We’re an evolutionary dead end insofar as we’re the cause of the sixth mass extinction, which will claim us as well. There’s no reason to think that intelligence is particularly useful from an evolutionary point of view. It’s like those weird Edicaran quilted bag animals: kind of cool and weird, but going nowhere.
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Mar 14, 2021 05:57
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ate poo poo on live tv posted:Why does everyone assume that humans aren't special? Is that just one of the postulates Fermi requires for his paradox? I think we are genetic badasses that are the culmination of the survival of at least 5 mass extinction events over billions of years. That's pretty loving special. If 1 in 100,000,000,000 habitable planets have some species as smart as humans then there are like 5-10 billion intelligent species in the part of the universe we can observe.
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Mar 14, 2021 06:48
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Salt Fish posted:If 1 in 100,000,000,000 habitable planets have some species as smart as humans then there are like 5-10 billion intelligent species in the part of the universe we can observe. We’re only really able to observe planets in the Milky Way, though. Unless there were galaxy-scale engineering going on somewhere.
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Mar 14, 2021 06:52
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no, not that we can observe the intelligent species out there, it's that in the volume of the universe that we can observe, we can expect that 5-10 bn intelligent species live there anyway there's no real reason to think humans are special or unique -- lots of species on earth have survived more mass extinction events than we have. the best case for this was posted upthread (eukaryota is the miracle) but I think if that was an advantageous strategy sometime on earth it's not outrageous to think that the same conditions couldn't hold elsewhere. In either case it's a numbers game, and there are enough stars that even extremely rare things will happen many times.
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Mar 14, 2021 18:03
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Salt Fish posted:If 1 in 100,000,000,000 habitable planets have some species as smart as humans then there are like 5-10 billion intelligent species in the part of the universe we can observe. How do you know there are that many habitable planets in the observable universe?
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Mar 14, 2021 18:13
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I just looked up any estimate for habitable planets in our galaxy and then multiplied it by an estimate of how many galaxies are in the universe.
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Mar 14, 2021 18:24
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Salt Fish posted:I just looked up any estimate for habitable planets in our galaxy and then multiplied it by an estimate of how many galaxies are in the universe. Remember that when it comes to exoplanet numbers, we have what could barely be considered an educated guess; that estimate could be off by orders of magnitude in either direction.
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Mar 14, 2021 20:52
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The estimate could be off by like 9 or 10 orders of magnitude and it would still suggest we're still not alone in the universe. That's the whole point of the drake equation and the fermi paradox.
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Mar 14, 2021 21:45
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Antifa Turkeesian posted:We’re an evolutionary dead end insofar as we’re the cause of the sixth mass extinction Not yet and even though it looks pretty dire right now, it's not guaranteed that we will be extinct even after triggering the 6th.
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Mar 14, 2021 23:24
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ate poo poo on live tv posted:Not yet and even though it looks pretty dire right now, it's not guaranteed that we will be extinct even after triggering the 6th. as an aside, I wonder how future archaeologists will classify quotes like this while poking through the digital rubble of Late Stage Capitalist Apocalypse ruins: "hmm yes, this is an interesting opinion by ate poo poo on live tv, clearly the name of a great mind of their time that suggests refinement and intellectual discipline."
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Mar 15, 2021 20:12
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Pope Hilarius II posted:as an aside, I wonder how future archaeologists will classify quotes like this while poking through the digital rubble of Late Stage Capitalist Apocalypse ruins: "hmm yes, this is an interesting opinion by ate poo poo on live tv, clearly the name of a great mind of their time that suggests refinement and intellectual discipline." That goodbye wondrous femininity guy is more famous now than 99% of all Romans who ever lived.
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Mar 15, 2021 21:23
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i find some of these arguments baffling, though. a lot of planets, an inconceivably large number of planets, does not mean there's 5-10 billion intelligent alien races out there. i kind of hope there is because i don't go too much for this dark forest analogy that liu cixin fans go in for, but just having a lot of planets doesn't mean there's anyone else. we could still be the only intelligent (by whatever metric) race, maybe down to time alone
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Mar 16, 2021 03:53
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Even in the assumption that the universe is absolutely teeming with intelligent life, ‘time’ is still a huge factor. We’ve been listening and broadcasting for about 100 years or so. (Exact numbers don’t matter.) 100 is very very small in comparison to 4,500,000,000 years that the Earth has been around. Considering how many times we have been on the brink of catastrophic nuclear war, plus the accelerating mass extinction/ecological collapse/climate breakdown? If other intelligent species are even remotely like us, they won’t be broadcasting for very long. Honestly, the same argument applies whether you nuke yourself into the Stone Age a decade after discovering nuclear fission or if you go extinct over ten thousand years. The timespan that species evolve and go extinct on is incomprehensibly small in comparison to geological and cosmological timescales. Some species are outliers that survive a long time generally unchanged, and there are some situations in which evolution operates slower, but the general point remains: time is not on our side when it comes to existing at the same time as another intelligent civilization, while one or both of us are capable of detecting the other. Regardless of intelligent life, astronomical technology is advancing to the point where the upcoming generation (or the one afterwards) of telescopes and instrumentation will make it possible to discern atmospheric compositions of rocky exoplanets in the habitable zone, on a scale in which we can actually do statistical analyses. There is a cruel irony in that over the next several decades we will finally begin to get a handle (even a vague estimate) on where Earth lies with regard to habitability and how rare planets like Earth might be...at the same time as we drive ourselves into an ecological catastrophe, destroying the conditions that made it possible for us to reach this point.
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Mar 16, 2021 04:24
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Antifa Turkeesian posted:We’re only really able to observe planets in the Milky Way, though. Unless there were galaxy-scale engineering going on somewhere. Such a thing might be seen as a natural phenomena. Do you think ants recognize that skyscrapers are artificial
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Mar 16, 2021 06:49
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What's the most boring answer to the Fermi Paradox? That's the one that's most likely to be true. So here we go: we're not special or unique, and there are lots of other intelligent civilisations out there, but they're all too far away for us to ever even get a glimpse of their existence. They're all doing the same poo poo we are 500 million light years away, being dumb morons that do idiot crap all day. Space is cool but is too big to meaningfully explore, we're stuck and dead and gay.
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Mar 16, 2021 11:38
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mediaphage posted:i find some of these arguments baffling, though. a lot of planets, an inconceivably large number of planets, does not mean there's 5-10 billion intelligent alien races out there. i kind of hope there is because i don't go too much for this dark forest analogy that liu cixin fans go in for, but just having a lot of planets doesn't mean there's anyone else. we could still be the only intelligent (by whatever metric) race, maybe down to time alone that's what the fermi paradox/drake equation are all about though: once your numbers get big enough even incredibly rare things start to pop up all over the place, so to resolve the paradox you either need a miracle (abiogenesis or multicellular organisms are super, super, super rare, maybe even to the point of actual uniqueness) or a "great filter" extinction event that all intelligent life, or all life in general tends towards (climate collapse, megaeruptions, gamma ray bursts, impact events, etc) I think "time" is the correct answer for why we won't find anything or anyone while we're still, like, comprehensibly human. The longer we stick around, though, the longer we might at least find artifacts of extinct or transcended or whatever aliens. Post-post-post-post humans (if we manage to survive that long) might find modern human equivalent aliens, but that might only be as interesting as finding some ants in the park or something, and that might be happening now with aliens we don't have the ability to contact or maybe even perceive. Or there might be some sort of hard limit to how complex or interesting anyone or anything can get, and if that's true in some sense a long existence would probably see us meeting a few aliens, at least. Anyway that's all to say that I think the real answer to the paradox is that things are weird out there and we're still in our infancy as a technological species.
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Mar 16, 2021 18:27
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