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

Posted by EditorDavid on from the we-are-actually-alone dept.

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?

11 of 435 comments (clear)

  1. time and distance scaling by cats-paw · · Score: 5, Interesting

    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.

    --
    Absolute statements are never true
    1. Re:time and distance scaling by Anonymous Coward · · Score: 2, Interesting

      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.

    2. Re:time and distance scaling by JoshuaZ · · Score: 5, Interesting
      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 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 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.

      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.

    3. Re:time and distance scaling by cirby · · Score: 4, Interesting

      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.

    4. Re:time and distance scaling by Tablizer · · Score: 5, Interesting

      Not necessarily. It's a matter of economics. Sometimes it's cheaper to waste energy than spend resources on efficiency. If fuel is relatively cheap, then efficiency may not be worth the added cost.

      --
      Table-ized A.I.
    5. Re:time and distance scaling by slack_justyb · · Score: 5, Interesting

      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.

    6. Re:time and distance scaling by The+Grim+Reefer · · Score: 4, Interesting

      Because life, at least from the baseline we have on our planet, tends to expand exponentially.

      Using our own planet, it appears that once a culture reaches a certain level of advancement, it may not continue to expand. Look at Japan. The US would likely be stagnant if it wasn't for immigrants. The EU is similar. What happens when and entire planet gets to the level of first world nations, or more advanced? Once the cultural pressures of getting married and having children subside, will the population continue at these rates?

      Look at how diverse life is on our planet. It's probably more so else where. Ant and bees have extremely different societies from humans. Or coral colonies. Just think if a species breed only by division. What if the offspring retain all of the memories of their parents? What if their lifespan was only 5 years? How much different it would be if a species lived 10 or 100 times as long as we do. Perhaps most species that evolved off of this planet aren't as curious as we are, or aren't as aggressive as humans. Hell, our ancestors could have evolved on another planet with several other intelligent species and they decided that we were too damn aggressive and banished us here. Who knows.

  2. Civilizations, I'd understand. by RyanFenton · · Score: 3, Interesting

    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

  3. Do you still use AOL Instant Messenger? by BLToday · · Score: 5, Interesting

    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.

  4. Silly by Dunbal · · Score: 4, Interesting

    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.

    --
    Seven puppies were harmed during the making of this post.
  5. Re:We could prevent the Great Dying by Anonymous Coward · · Score: 2, Interesting

    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 generate hydrogen. H2O is also a greenhouse gas, but we have a plenty good process to get H2O out of the atmosphere: rain.