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Astrophysicist Believes Technologically-Advanced Species Extinguish Themselves (sciencedaily.com) 435

Why haven't we heard from intelligent life elsewhere in the universe? wisebabo writes: In the Science Daily article "Where is everybody? The Implications of Cosmic Silence," the retired astrophysicist Daniel Whitmire explains that using the principle of mediocracy (a statistical notion that says, in the absence of more data, that your one data point is likely to be "average"), that not only are we the first intelligent life on earth but that we will likely be the only (and thus the last) intelligent life on this planet... Unfortunately that isn't the worst of it.

Coupled with the "Great Silence", it implies that the reason we haven't heard from anyone is that intelligent life, when it happens anywhere else in the universe, doesn't last and when it does it flames out quickly and takes the biosphere with it (preventing any other intelligent life from reappearing. Sorry dolphins!). While this is depressing in a very deep sense both cosmically (no Star Trek/Wars/Valerian universes filled with alien civilizations) and locally (we're going to wipe ourselves out, and soon) it is perhaps understandable given our current progress towards reproducing the conditions of the greatest extinction event in earth's history.

That last link (reprinting a New York Times opinion piece) cites the "Great Dying" of 90% of all land-based life in 252 million B.C., which is believed to have been triggered by "gigantic emissions of carbon dioxide from volcanoes that erupted across a vast swath of Siberia." But if we're not headed to the same inexorable doom, that raises an inevitable follow-up question.

If intelligence-driven extinction doesn't explain this great cosmic silence, then what does? Why hasn't our species heard from other intelligent civilizations elsewhere in the universe?
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Astrophysicist Believes Technologically-Advanced Species Extinguish Themselves

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  • by cats-paw ( 34890 ) on Sunday August 13, 2017 @04:46PM (#55004389) Homepage

    As has already been demonstrated by the permian extinction event, the biosphere can take a hell of a hit, and life will go on.

    I think that you really have to understand timescales here. A 100 million years is a long time, just like space is big, really big. So that's a long damn time, and life will go on. intelligent life, maybe not so much.

    as for why we haven't heard from anyone, why isn't the simple answer not the best ?
    Remember how space is really big ?

    if there's no FTL travel, and it's likely there is not, then HOW would we hear from someone ?

    It would be an exceedingly difficult thing for the intelligent civilization in the Andromeda galaxy to talk us, and us to them.

    First of all, there's the 2,000,000 year latency, and then the amount of power you would need to transmit that signal, etc...

    I'm not worried. There's intelligent life elsewhere in the verse. I'm pretty sure we're not going to hear from them any time soon, if ever.

    • Re: (Score:2, Interesting)

      by Anonymous Coward
      And of course if they were so advanced that we could actually hear from them - would we want to? Would an amoeba want to hear from us? Probably not. And would we try to have a conversation with an amoeba? Nope, not worth it. I guess it may be humiliating for some people but we as a species are probably not interesting at all to a extrasolar species that is advanced enough that they could come here or at least figure out a dodge to communicate with us.
    • by amiga3D ( 567632 )

      More likely they destroyed themselves. I look at the insanity on this planet and I'm pretty sure that nuclear war is inevitable. When it was 3 nations it was controllable. Now we have nations like Pakistan, North Korea and Iran. How long before Syria, Venezuela, Somalia. Once building a nuke was a challenge requiring SuperPower status. Now it just requires maniacal determination.

      • by thinkwaitfast ( 4150389 ) on Sunday August 13, 2017 @05:26PM (#55004615)
        Nuclear war is very messy, but won't exterminate life. Especially human life.
        • by amiga3D ( 567632 )

          Maybe not. But it's possible that it will. I'm sure life will go on but humanity may not.

          • by MrKaos ( 858439 )

            It's probable radionucides released into biomes from our experiments and accidents from nuclear power will alter the genome of humanity and increase the prevalence of transgenic disease over time, along with pregnancies that fail to come to term.

            Societies need energy and the fact that some materials are fissionable as a source of energy raises the possibility that other species in the galaxy may go through this phase as well. If we consider that fissionable materials have the capacity to alter DNA in a rea

      • by cirby ( 2599 ) on Sunday August 13, 2017 @06:05PM (#55004829)

        More likely they destroyed themselves. I look at the insanity on this planet and I'm pretty sure that nuclear war is inevitable. When it was 3 nations it was controllable. Now we have nations like Pakistan, North Korea and Iran. How long before Syria, Venezuela, Somalia. Once building a nuke was a challenge requiring SuperPower status. Now it just requires maniacal determination.

        If we fired off every single nuclear weapon ever built - every nuke in all of the world's arsenals - we couldn't come vaguely close.

        At most, with perfect targeting of population centers and no evacuation before hand, we might lose as many as a billion people. Which is a lot, but that would leave about six billion people to pick up the pieces. And yes, that includes ALL weapon effects, from the initial blast to fires to fallout.

        Even assuming that another billion would die from starvation and other indirect effects (a massive overassumption), you're still looking at a surviving population greater than the Earth's population in the early 1990s.

        The ultra-silly gloom-and-doom scenarios like "Nuclear Winter" have long since been disproved (their catastrophic models were too simple, and made some crazy assumptions).

        I know it's fun to pretend that "if you don't listen to us, everyone's GONNA DIE," but it's just not happening. We're not anywhere near powerful enough to manage it.

        • If we fired off every single nuclear weapon ever built - every nuke in all of the world's arsenals - we couldn't come vaguely close.

          Exactly. There have already been thousands of nuclear detonations on the planet. Someone will reply with the "all at once" argument, but while a nuclear winter will suck, we've got clothing and canned foods. Some humans will absolutely survive.

    • well said, this is the right answer plain and simple

      intelligent life is rare and the universe is big...asked and answered...next question please!

    • by JoshuaZ ( 1134087 ) on Sunday August 13, 2017 @05:17PM (#55004563) Homepage
      The problem though isn't deliberate communication, but rather twofold:

      First, a complete lack of evidence on a large scale of anything we'd expect to see. We have some pretty concrete ideas about construction of megastructures, such as Dyson spheres, the more plausible Dyson swarms, stellar engines (where the Class A version https://en.wikipedia.org/wiki/Stellar_engine#Class_A_.28Shkadov_thruster.29 [wikipedia.org] is essentially doable if one has enough material and doesn't require any exotically strong materials or the like), and many more. But we don't see any signs of any of those. And most of those will *last* for very long times once constructed. And we have searched for them both here http://home.fnal.gov/~carrigan/infrared_astronomy/Fermilab_search.htm [fnal.gov] and in other galaxies. In a similar context, we've looked for signs of K3 civilizations in about 100,000 galaxies and found essentially no signs of them https://arxiv.org/abs/1504.03418 [arxiv.org].

      The second problem is that if a species does survive even a relatively small amount of time, it should be able to spread throughout a galaxy. Yes, galaxies are really big, but the space is not as big as the time available. For example the Milky Way is about 100,000 light years across. That means that if a species starts on one end and travels spreading throughout planets at around 1% of light speed (which certainly looks doable) then it takes around a 10 million years for them to spread throughout. That's a tiny amount of time. But we don't see any signs of anything like that.

      So there really does seem to be some sort of Great Filter or series of Filters, and the question is whether it is early (e.g. life is hard to arise or intelligence arises rarely) or late (civilizations wipe themselves out). And if it is the second, then we need to figure out what is going on since we don't get a do-over.

      • by Ramze ( 640788 ) on Sunday August 13, 2017 @07:11PM (#55005105)

        Or, maybe those mega-structures aren't really feasible -- and if they are, they aren't practical or economical. Maybe most life evolves around brown dwarf stars that won't burn out 'til near the end of the universe, and so the life on planets around those stars sees no reason to ever leave the nest. They have everything they need and decide to keep to themselves.

        Maybe there's life everywhere, but their communications are point-to-point lasers or some other method we just can't detect.

        Spreading life from one star system to another at sub-light speeds would mean generational ships, cryostasis, robots, and/or artificial wombs for incubating frozen zygotes. Maybe it's just not worth it for other civilizations to even bother -- at least until their sun is about to go nova... and even then, it's a huge, possibly enormously expensive risk, and politically... who gets to get on that life boat exactly? Maybe their philosophy, politics, or religion would prevent them from abandoning their dying world.

        The fact is -- we really don't know what we're looking for and haven't been listening for long enough to have any idea of what we may have missed. Surely civilizations rise and fall without us ever knowing. We've only been broadcasting ourselves for the past couple centuries out of the 4-5 billion years life has been on our planet. There's always the possibility that we are the first civilization in our corner of our galaxy (someone had to be first!). But there's billions of galaxies... and we can barely detect things in a small radius from our location in our own galaxy.

        We really don't have any data to work with. It'd be nice if we'd start sending probes to nearby star systems so that in a few thousand years, we'd know if any of them harbored life of some sort.

        • The energy levels available at brown dwarfs makes life unlikely to evolve there or do much. Note that even if we're wrong and life is common on brown dwarfs, that would still leave all the other locations where we actually have reason to expect there to be life.

          And there are lots of things that one wants to do that just require a lot of energy, including some megastructures such as large-scale computing systems. And it requires that every single species out there decides not to. Every single one making t

    • Just within our own galaxy, it's the height of arrogance to assume that any planet in the Milky Way would be able to detect our signals and decide to send a response in the time that we have been capable of detecting signals. Maybe they decided that we weren't actively trying to communicate, and ignored us. Maybe they detected us as a WOW! signal and haven't gotten around to deciphering the origin.

      That we would be a first priority for anyone remotely close, to decipher and send a response, is a stupid ass

    • by Nutria ( 679911 )

      Not only that, but the inverse square law means that if we get so few photons arriving from something as massive as a star, we won't be getting much from something as puny as a planet...

      • And if they did arrive they'd probably be encrypted and look like background radiation.

        • And if they did arrive they'd probably be encrypted and look like background radiation.

          Compressed data also looks random.

    • by slack_justyb ( 862874 ) on Sunday August 13, 2017 @06:50PM (#55005021)

      if there's no FTL travel, and it's likely there is not, then HOW would we hear from someone ?

      You say that, but that totally invalidates what you said prior to that.

      A 100 million years is a long time

      The Andromeda galaxy is only 780 kpc from us. At 99% the speed of light, that's only 2.5 million years. On a scale of 100 million years, that's totally doable multiple times over. That's the huge mystery of the Fermi paradox. Given medium time scales like G-type main sequence stars lifetimes, alien life has had enough time to hop between the big three galaxies in our local group and do a fly-by of the main stars in all three as well.

      if there's no FTL travel, and it's likely there is not

      Yeah, it's insanely likely that FTL is just sci-fi forever. I personally think anything higher than 90% c is just non-doable. So look back at the last paragraph in my comment. Say we slow everyone down to just 10% c. At 10% c, you can hop from one side of the Milky Way to the other in just a million years. Get to Andromeda in just 25 million years. That's still really short time spans. You could fly to Andromeda, send a message back and the sun still wouldn't have entered it's next phase, one billion years from now compared to 27 million years for what I just described.

      First of all, there's the 2,000,000 year latency, and then the amount of power you would need to transmit that signal, etc...

      All of those are insanely small scale issues, they're big things to us because we lack the ability to even fly to another planet, but if you're the type of society that can fly at 10% c, those are pretty simple tasks that might take 10k years to build a generator, 15k years to build the transmitter, etc. They just seems like big deals because we're nowhere near that kind of specie.

      So millions of years is not a huge amount of time. But more importantly, becoming a traveler of the stars means you don't hold on to where you came from. You travel to Andromeda, that's who you are now. You don't have strong ties to Earth anymore, you're a seed of life, not an explorer. Humanity still clings to this notion that once we start, if we start, traveling the stars that we'll for some reason still treat Earth as this special place that we need to come back to or at the very least report back to. We might send a message, but after that, those humans are now their own thing. The idea of sending people to other planets isn't to save Earth, it isn't even to save our species because more than likely after a few thousand years on a different planet your DNA is going to change vastly. It's to save intellect, to keep the thinking/feeling part of the Universe going. As far as we know we're the first/only part of the universe that's got the thinking attribute and maybe just like how supernovae spread heavier elements, we need to get our butts in gear to start spreading this attribute across the galaxies (just the local group, the idea that we'll ever make it out of the local group is not even real with any kind of advancement). But that's just my take.

    • by MrL0G1C ( 867445 )

      The Sun is getting hotter, there is nothing to say that this big extinction event won't be the last. Sooner or later Earth will end up like Mars or Venus, looks like it could actually be sooner since we don't have enough self control not to over reproduce and we seem to be hellbent on digging every bit of fossil fuel out of the ground and burning it. And that's not the worst of it, a slight temperature increase will lead to massive methane releases. Scientists are failing to tell us how much shit we're in.

  • Obvious answer (Score:3, Insightful)

    by Anonymous Coward on Sunday August 13, 2017 @04:47PM (#55004397)

    The universe is just too big to hear anyone else.
    Standing on the shore in Spain you couldn't hear anyone shouting from Hispaniola, yet when Columbus landed there he found loads of people. Space is a hell of a lot bigger than the Atlantic Ocean and relatively any radio signal we can send is quieter than the man screaming on the beach in our example. So quit it with the all life will destroy itself pessimism.

    • Re:Obvious answer (Score:5, Insightful)

      by rudy_wayne ( 414635 ) on Sunday August 13, 2017 @04:56PM (#55004445)

      The universe is just too big to hear anyone else.
      Standing on the shore in Spain you couldn't hear anyone shouting from Hispaniola, yet when Columbus landed there he found loads of people. Space is a hell of a lot bigger than the Atlantic Ocean and relatively any radio signal we can send is quieter than the man screaming on the beach in our example.

      This.

      People just really don't understand the enormity of the universe. There could be lots of life out there but all of it is simply too far away. Even if they have invented some sort of Star Trek-style faster-than-light technology, it would take them hundreds or thousands of years to reach us. Which is unlikely since they don't even know that we exist. Any radio signals that we have sent won't reach them for a few thousand more years.

    • > Standing on the shore in Spain you couldn't hear anyone shouting from Hispaniola, yet when Columbus landed there he found loads of people.

      excellent analogy

    • Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space.

    • by mpercy ( 1085347 )

      In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.

    • Yet today you can pick up a phone and immediately talk to someone. Technology spanned the distance. You aren't giving a reason why it wouldn't do so again given enough time.
      • by green1 ( 322787 )

        Your phone doesn't get anywhere without another phone at the other end and a whole lot of infrastructure in between.
        Radio signals only travel so far before they're too weak for us to differentiate from the background noise, especially when we don't know what we're looking for.

  • TIME is V A S T (Score:5, Insightful)

    by redelm ( 54142 ) on Sunday August 13, 2017 @04:47PM (#55004401) Homepage

    Not only is space incomprehensibly vast, but so is time. 16 billion years sounds easy to say, but if an intelligent species only broadcasts "clear", identifiable uncompressed unencrypted radio for ~100 years, then we have only 1 in 160 million chances of finding them with something like SETI.

    • by green1 ( 322787 )

      It's even worse than that, the signal has to be in some form of format that differentiates it from background noise, on a frequency that we are monitoring, and strong enough to hear. So it's not just about the narrow time frame it has to have been sent in to reach us, and for us to have received it, there's also the exact method of sending, and a signal strength that raises it above the noise floor.
      Unfortunately I agree that there's a high risk that any intelligent species would wipe themselves out. We kno

  • by wonkey_monkey ( 2592601 ) on Sunday August 13, 2017 @04:56PM (#55004449) Homepage

    So by these principles of mediocrity is all civilised life also bipedal, with two eyes, two arms, and five digits on each extremity?

  • by RyanFenton ( 230700 ) on Sunday August 13, 2017 @04:59PM (#55004463)

    Across several million years, yeah the bulk of large civilizations may just fall to entropy of some crucial resource they can't build past. ...but with sufficient civilization, you'd create artificial intelligences and artificial life.

    Those would scale far better over time, and would be far less vulnerable, and across millions of years would be nigh-innevitable.

    Even if they're just existing as spores that hop from star-orbit-to-asteroid-to-star-orbit, they'd build up to an enormous mass over time, and be able to try an enormous number of strategies for continuing existence through networking.

    The artifacts and legacy of civilization should stand a much greater chance of returning communication over time than just civilization alone.

    But perhaps to those creatures, we're the common noise that they have learned to ignore.

    Ryan Fenton

  • by Sique ( 173459 ) on Sunday August 13, 2017 @04:59PM (#55004465) Homepage
    You find a nice writeup about the Cosmic Silence and possible reasons for that in Stanislaw Lem's essay "Summa technologiae", published in 1966. Apparently, not much has changed in the last half a century.
  • by BLToday ( 1777712 ) on Sunday August 13, 2017 @04:59PM (#55004467)

    We're using AIM and we assume if people have internet connection then they must also use AIM. If we see no one on AIM then there must be no one else with an internet connection.

    I'm with the theory that we're just at the beginning of life in this part of the universe. 13.7 billion years from the Big Bang. Multiple generations of star formation and death before getting to our Sun. Then another 4 billion years before complex life. Sounds like it takes awhile for intelligent life to get started.

    • by Calydor ( 739835 ) on Sunday August 13, 2017 @06:26PM (#55004919)

      But we don't really understand why WE developed intelligent life.

      Why didn't the dinosaurs? There could have been intelligent life (in the sense of tool use, construction etc.) a quarter billion years ago, but as far as we can tell there wasn't. There was only semi-intelligent life (in the sense of mobility, family structures etc. compared to plant and microbe life, ie. animals).

      • What if we're all using Facebook, but they're all using *Spacebook*. Whoa.
      • by Jeremi ( 14640 )

        Why didn't the dinosaurs? There could have been intelligent life (in the sense of tool use, construction etc.) a quarter billion years ago, but as far as we can tell there wasn't.

        Was there much evolutionary pressure on the dinosaurs to develop intelligence? Perhaps sharp teeth, impressive sizes, and/or thick skin was sufficient to keep them reproducing (up until their extinction, anyway). Evolution doesn't seem to care much about optimizing any further than "good enough to reproduce".

  • by Blythe Bowman ( 4372095 ) on Sunday August 13, 2017 @05:03PM (#55004489)
    ....but they know better not to contact our violent, religious crazed, heartless and fucked up world
  • by globaljustin ( 574257 ) on Sunday August 13, 2017 @05:08PM (#55004511) Journal

    If intelligence-driven extinction doesn't explain this great cosmic silence, then what does?

    They just aren't there! Why can't people of science accept this?

    It's sometimes called the Rare Earth Hypothesis [wikipedia.org] but KS Robinson really explains it well in his Mars Trilogy books.

    Basically the theory goes that lower level life may or may not be 'common' in the universe, but intelligent life is so rare that given distances and the speed of light and whatnot we just probably won't ever encounter each other.

    It's elegant and explains everything and should be the accepted theory in exobiology (if it isn't already) until evidence proves otherwise.

    • by swb ( 14022 )

      The funny thing is that by the end of the series, humans were becoming interstellar.

      They had "the treatment" that gave humans lifespans of at least 300 years (and based on the trends in the book concerning Sach's memory treatment) it might stretch to double or triple that.

      They had mastered fusion energy in a portable format, giving them the ability to put it in spacecraft.

      And Jackie had joined a group traveling to a nearby star system in a hollowed out asteroid to a human-habitable planet.

      If humans managed

      • If humans managed all that in some 300 years, you'd almost expect they would be broadly interstellar in the next 1000.

        I *think* the author touched on this in the text (maybe in one of the 'in universe' scientific papers in the index?).

        I think the jump to a new star is huge, but the jump to another galaxy is just sort of beyond anything we can rationally predict given the advances in tech to do such a thing. We'd have to have some kind of 'time ship' like in ST:Voyager to visit another galaxy and report anyt

        • by swb ( 14022 )

          Even in Star Trek, crossing the entire galaxy is a big deal and other galaxies aren't even really possible.

    • by phantomfive ( 622387 ) on Sunday August 13, 2017 @05:34PM (#55004679) Journal

      They just aren't there! Why can't people of science accept this?

      They don't accept it because it's just a hypothesis, and although it is reasonable, it is just one of many hypotheses that explain the current evidence.

      In the absence of further evidence, there will be no way to tell which of the hypotheses is correct, and choosing one prematurely isn't helpful.

      • They don't accept it because it's just a hypothesis, and although it is reasonable, it is just one of many hypotheses that explain the current evidence.

        In the absence of further evidence, there will be no way to tell which of the hypotheses is correct, and choosing one prematurely isn't helpful.

        Good feedback.

        In response I'd say let's compare to Physics theories that are "just a hypothesis" that have weaker evidence yet treated as fact. I think that *comparatively* we have more reason to think "they aren't t

    • Here's another possibility: Since the space race, we've not actually progressed that far in terms of space travel. If the world was completely at peace, and we had no reason to wage war, life is great, etc, there is pretty much no reason to go up there.

      Our primitive, brutish nature is probably the reason we got to space in the first place. There could be lots of intelligent life out there, and they could be too intelligent for their own good. You can see a similar trend on Earth with the tree huggers/etc. L
      • I don't see any evidence that humanity progresses faster through war.

        Just because some technology was advanced by war necessity doesn't mean it's the only or best way at all.

      • The Nazi's were the first ones into space, passing the Karman line in the 1940's, The first computers were used for ballistic trajectory solutions. The science historian James Burke once said that the only thing that science has historically been good for is making money and war. Most of today's technology is a result of WWII and the cold war.
    • by meglon ( 1001833 )
      You're actually saying two different, and mutually exclusive ideas there. Either A: they are not there; or B: they are there, but the universe is so big we'll just never encounter them. Those two ideas are opposite of each other.

      As for why scientists can't accept the idea of "they simply aren't there," i imagine a great deal of it is the incredibly small probability of us being the only one considering not only how incredibly vast the universe is, but what's shaping up to be how many planets are out the
  • Actually, we're red-zoned because we alone of all the intelligent species in the galaxy got the definitions of "male" and "female" backwards, and they're afraid we'll have a massive cognitive meltdown when we find out.

  • by Dorianny ( 1847922 ) on Sunday August 13, 2017 @05:13PM (#55004533) Journal
    Of all the Homo genus we are the only one that did not go extinct. Whatsmore there is so little genetic varation in humans that researchers believe we decended from a population of as few as 2000 individuals. With such numbers humans were basically on the critically indengered list. Why would you go make up some theory about intelligent life inevitably destroying itself when intelligent life on this planet nearly went extint without ever sending a signal that intelligent life existed on this planet
  • by John Jorsett ( 171560 ) on Sunday August 13, 2017 @05:16PM (#55004555)
    For all we know, the universe is all chatting with each other via quantum entanglement or something even more advanced, and we're off in the corner thwacking our electromagnetic equipment on the side saying, "Is this thing on? Where is everybody?"
  • Silly (Score:5, Interesting)

    by Dunbal ( 464142 ) * on Sunday August 13, 2017 @05:31PM (#55004663)

    If intelligence-driven extinction doesn't explain this great cosmic silence, then what does? Why hasn't our species heard from other intelligent civilizations elsewhere in the universe?

    Distance. Distance in space, which renders actually finding another civilization impossible. And distance in time. Any number of civilizations might have already risen and fallen, or will after we are gone. The universe is very very big, and very very old. To expect everything to happen in the instant we are around and aware is quite short-sighted.

  • by Tony Isaac ( 1301187 ) on Sunday August 13, 2017 @05:41PM (#55004713) Homepage

    It seems a bit early to write off humanity as extinguishing itself. Yeah, so we've heated up the planet, and we put trash where it doesn't belong. But excesses do tend to undo themselves, as we can see with even China and India starting to curb emissions. Survival is a powerful instinct, and it hasn't been exhausted just yet.

  • by Solandri ( 704621 ) on Sunday August 13, 2017 @05:43PM (#55004727)

    cites the "Great Dying" of 90% of all land-based life in 252 million B.C., which is believed to have been triggered by "gigantic emissions of carbon dioxide from volcanoes that erupted across a vast swath of Siberia.

    Our technology is to the point where we could prevent a recurrence of the Great Dying. All you have to do is unshackle your mind from the popular notion that the only solution to CO2 emissions is passive (reducing emissions via renewable energy sources).

    CO2 (and water) are popular end-products for exothermic chemical processes (e.g. burning gasoline, cellular respiration) because it sits at an extremely low energy potential [wikipedia.org]. That is, chemical processes which result in CO2 give off a lot of energy. To reverse the process, you have to put a lot of energy into the CO2 to break apart the carbon and oxygen atoms.

    If you have sufficient energy, you can actively drive that reverse process. Plants do it via photosynthesis, driving it with energy from sunlight. We could do it with nuclear power - generating massive quantities of electricity (more than can reasonably be obtained from solar, wind, hydro) to decompose CO2 [acs.org]. Generating sufficient power to offset volcanic emissions of CO2 would be incredibly expensive, but given the alternative (extinction) we're technologically capable of doing it.

    The same is true if this push for renewables as the only solution to global warming fails. If renewables can't be developed quickly enough to supplant fossil fuel energy sources and CO2 levels continue to rise, at some point we concede that renewables aren't arresting CO2 levels quickly enough. Then we'll be forced to switch to nuclear power to buy ourselves more time. This is why shuttering operational nuclear plants as Germany is doing is extremely short-sighted. Nuclear is our ultimate trump card. We want to keep it ready in our back pocket as a hedge in case renewable energy can't be rolled out quickly enough.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      The main problem with getting CO2 out of the atmosphere isn't energy but entropy. By far the biggest part of the atmosphere isn't CO2, but N2. O2 is also common. Together the two make up 99% of the atmosphere. So getting those CO2 molecules out means ignoring the vast bulk of molecules which aren't CO2. That's why prevention is more effective. If you prevent the formation of CO2, or you capture it after formation, you don't need to isolate it from the atmosphere.

      That's why you'd want to use nuclear power to

    • I don't think you've thought too much about the scale of your plan.

      We're not talking about 100 nuclear-powered CO2-capture plants here. We're talking about hundreds of thousands to millions in order to do have any effect within a reasonable timeframe.

      While it is likely we will actively remove CO2 from the atmosphere in the future, it's not viable to have this be the only thing we do.

  • Maybe we haven't heard from other species because it is physically impossible to bridge the light-years gap. Maybe faster than light information transmission, let alone faster than light travel, is not possible. Maybe intelligent species appear, on-average, hundreds or even thousands of light years away from each other, and the chance of any two species being sufficiently close to overcome the distance problems is astronomically small. Physics seems to suggest that bridging such distances is virtually impos

  • Even if intelligent civilization extinct themselves, we should still see their TV broadcasts before their extinction.

    One possible explanation is that earth-based life made it to radio-emitting civilization the fastest as possible, and no other civilization elsewhere made it sooner enough so that we could see their radio emission.

    But unfortunately, that explanation is not incompatible with us extinguishing ourrselves.

  • I think we're suffering a failure of imagination.

    Perhaps our ability to modify ourselves is going to outpace our ability to get enough people off of the planet to keep our population in check (maybe 100 million per year or so?).

    This will drive us to start modifying ourselves and our way of living to require less resources. Ultimately, that should end as a people with no physical bodies living in a virtual world far more fantastic than the real galaxy due to not having to follow laws of physics in its models

  • Meat [terrybisson.com]

  • The atmosphere was different during the time of the dinosaurs. Maybe a raptor-decented intelligent race could have appeared ina few millions years if the meteor hadn't hit? I just think that it's impossible for one intelligent race to ruin a planet for other species to emerge. There could be some new species that emerges post-humans that will like the hot, CO2-rich, irradiated cinder we leave behind?

    • It took a long time to get from the first cell to Aristotle. It took a lot of the planet's readily available resources to get from hunter-gatherers to the Information Age.

      There likely isn't enough time left, and certainly not enough resources left, to allow for an equivalent technologically advanced intelligence to arise on this planet if we wipe ourselves out.

      • It took 60million years to go from a mouse to people walking on the moon. Dinosaurs were around 3x longer than that...160 million years.
  • We've been looking for RF transmissions. Those fall off at 1/d^2, so they're quickly going to fall to an intensity that is extremely difficult if not impossible to isolate from background noise.

    Second, civilizations get quieter over time (assuming we're typical). Our massive analog TV and radio transmitters have been replaced with much weaker digital transmitters. The transition from our peak noise to our now much quieter noise took about 40-50 years. That's not a lot of time to be noticed.

    In addition,

  • It just dawned on me what the problem is: the Intergalactic ASCAP got our solar system region-locked so we can only hear our own stuff.
  • Why hasn't our species heard from other intelligent civilizations elsewhere in the universe?

    Our ability to detect civilizations is currently based on them producing high power omnidirectional radio signals.

    Our own species, after a little more than a century of use, we are already increasingly abandoning that technology in favor of things like fiber optics and low power spread spectrum radio. It could be that intelligent civilizations aren't silent, they've just stopped using telecommunications we can easil

  • When you ask a historian about biology, you get crappy answers.

    Astrophysicists are not specialists in non-human life, non-human psychology, or anything else related to this.

    Wrong scientific field means you get a stupid answer.

  • by Black Parrot ( 19622 ) on Monday August 14, 2017 @01:52AM (#55006351)

    In any viable biological system, intelligence evolves without bound.

    Until it invents an internet, at which point it quickly drowns in its own vice and stupidity.

Ocean: A body of water occupying about two-thirds of a world made for man -- who has no gills. -- Ambrose Bierce

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