In the Kardashev Scale, a Type II Civilization would build a Dyson Sphere around their star. A team of astronomers are searching for them.
  • Tylerdurdon@lemmy.world
    48·
    6 months ago

    Okay, so the title is a bit off. They’re hunting for partial Dyson spheres using infrared and optical.

    I was confused on how they would detect something completely blocking a sun from millions of light-years away.

    • GreyEyedGhost
      311·
      6 months ago

      Even a Dyson sphere, which is technically unlikely anyway, would be possible to spot. You would look for something very bright in the infrared spectrum with almost no light in the visible spectrum. It would also be larger than a normal star of the same energy, but that would be hard to tell given all the other issues.

      A partial swarm is easier because it will have variability towards more infrared and then back to a more normal spectrum.

      And, of course, all this is speculation until we find a candidate and determine it doesn’t have a natural source for that behavior.

      • FooBarrington@lemmy.world
        6·
        6 months ago

        Why would there necessarily be strong infrared emissions? Since a Dyson Sphere is meant to harvest all energy produced by a star, any leakage would be unnecessary inefficiency, wouldn’t it?

        • GreyEyedGhost
          111·
          6 months ago

          Thermodynamics says that energy can’t be destroyed (mass-energy, but generally that won’t matter). So after the work of running your stellar civilization is done, you will radiate out waste heat. There is no real way around this without breaking thermodynamics or having a handy black hole to dump all your waste heat into. Therefore, the energy of the star will still be released, but it will be released as infrared.

          • FooBarrington@lemmy.world
            4·
            6 months ago

            If you’re using the Dyson sphere purely as a power plant and e.g. charge batteries, the thermal radiation will be distributed over the whole area covered by the civilization.

            A solar panel, or any other power generator we use, doesn’t radiate away all the generated energy either. It’s radiated from the point of use.

            • GreyEyedGhost
              4·
              6 months ago

              So you heat habitats, which radiate heat. And run computers, which radiate heat. And move objects around, which radiates heat (among other things). And if you merely absorb energy from your star…it radiates as heat. This is the whole idea of entropy. Unless your lasers are particularly efficient and you use them to beam the energy elsewhere, your Dyson swarm is going to radiate heat equivalent to the energy your star puts out.

              • FooBarrington@lemmy.world
                2·
                6 months ago

                You’re ignoring my example - what if you charge up batteries at the Dyson sphere, and use the energy anywhere else? There’s no physical reason the energy must be used around the Dyson sphere.

                • GreyEyedGhost
                  3·
                  6 months ago

                  So all you need is a perfect charging system. We don’t have those, and physics doesn’t allow for them. This would be no different than the laser example I gave, and this only makes sense after you have a second Dyson swarm.

            • Echo Dot@feddit.uk
              1·
              6 months ago

              But you would still be radiating heat from that star system unless you’re proposing wireless energy transfer over Interstellar distances. So the entire system would still give off an unusually high infrared signature.

              • FooBarrington@lemmy.world
                1·
                6 months ago

                I’m not proposing that - I literally wrote my idea in the comment you replied to: a potential alien civilization could charge up batteries at their Dyson sphere, and use the energy anywhere else in the galaxy. You know, the way EVs work.

        • Passerby6497@lemmy.worldEnglish
          3·
          6 months ago

          Because all that energy contains heat as well, and you’ll need to balance the heat from your star along with the energy absorbed.

          You’re never going to get to 100% efficient conversion, so you’ll have to radiate away the heat so your sphere doesn’t melt or something.

    • ShittyBeatlesFCPres@lemmy.worldEnglish
      214·
      6 months ago

      Dyson swarms are more likely. We even have a tiny one with our satellites using solar power in a heliocentric orbit. (Dyson spheres are basically impossible.) But we could theoretically detect either in infrared since if it doesn’t give off waste heat, it’d all heat up and melt.

      That being said, I’m personally of the opinion this is a waste of time. Not to get all Fermi Paradox but it’s pretty sci fi brained to think any other species out there is as dumb as we are. Space sucks. You die super fast there. Everything had to align just right for Earth to make a bunch of dumb fuck apes willing to strap themselves onto rockets, have a planet small enough that the rocket could even overcome gravity to enter orbit using chemical rockets, and a World War and Cold War to accelerate things.

      • LordGimp@lemm.ee
        8·
        6 months ago

        Time will always be the great filter. Even if we did spot a Dyson swarm, we have no feasible way to contact anything on a practice timescale. Any speck of civilization we detect will be hundreds of thousands of years out of date at best, billions at worst. Life in the universe, imo, is basically guaranteed. If it happened once, it can happen again. Meaningful contact between separately evolved concurrent sapient species? Not likely.

      • Echo Dot@feddit.uk
        3·
        6 months ago

        Everything had to align just right for Earth to make a bunch of dumb fuck apes willing to strap themselves onto rockets, have a planet small enough that the rocket could even overcome gravity to enter orbit using chemical rockets, and a World War and Cold War to accelerate things.

        Given the estimated number of planets in this galaxy alone, it’s particularly guaranteed that very similar events have occurred on multiple worlds. Unless you’re proposing that all theoretical alien races are Vulcan level logical then tensions and interstate conflicts will always exist that will advance technology. This is practically an inevitability unless the race question is a hive mind species.

        • ShittyBeatlesFCPres@lemmy.worldEnglish
          2·
          6 months ago

          I think my Fermi Paradox explanation is that space is really fucking big and hostile and protecting the planet you evolved on is the only real option.

          • Blóðbók@slrpnk.net
            21·
            6 months ago

            Not to mention the problem of what life is even supposed to do beyond a certain point of development. The depressing fact is that there is a finite amount of knowledge to be gained, a finite amount of resources to harvest, a finite diversity of life to contend or thrive alongside with. Once a pocket of life in this massive universe begins to run out of things to do and stagnates, then what? What is there to think about; to feel; to experience?

            There’s little point in exploring space if one know how this universe works. One knows the rules, knows all the ways it can play out, and there’s no surprise waiting on the other end of any venture one can imagine embarking on.

            That’s my theory. The Great Filter is just depressive boredom. We don’t see other life because by the time a civilisation is able and ready to spend thousands of years travelling through deep space, they’ll have already lost any motivation they might have had to do so.

            I suspect that there’s at best a very short window wherein a species is both knowledgeable enough to dream of space exploration and technologically capable of sending any significant amount of artificial constructions out there.

            Not to mention that anything an alien species might send into interstellar space is unimaginably unlikely to be recorded exactly at precisely the moment they pass another lump of matter - especially if the window is as short as I fear.

    • Echo Dot@feddit.uk
      3·
      6 months ago

      If it was actually completely enclosing a star that would be impressive. It would also be a bit pointless, since It would result in your spear heating up to stupid temperatures, Which would cause it to glow in the infrared, so you would detect it by that infrared.

      • Simulation6@sopuli.xyz
        3·
        6 months ago

        Isn’t the idea that the sphere would have a circumference the size of earths orbit? Not sure it would heat up all that much to be noticeable.

    • AA5B@lemmy.world
      201·
      6 months ago

      Agree this sounds ridiculous, but isn’t this the basic point of science? Propose something is possible, then make predictions and see if you can prove or disprove. The Dyson Sphere idea itself is ridiculous, but to the extent you can detect large scale technology around a star, that would be fantastic. Even better, this is simply a query on existing data. Imagine if they detected intelligent life this way!

      Kind of reminds me of the search for Dark Matter. That whole idea sounds so preposterous yet is the best fit for our current knowledge. But we can make predictions based on this. What could all this matter be to fit the theory while remaining undetected so far? Then you can build particle detectors to find them and particle accelerators to explore conditions for causing them. Eventually we should be able to either detect that matter or to rule out enough possibilities for another theory to better fit our knowledge

    • Echo Dot@feddit.uk
      91·
      6 months ago

      We don’t really know that building a long-term colony on the Moon or Mars is feasible. We assume that it is because there’s no obvious reason that it isn’t possible other than it being difficult, but that’s just a matter of working up to the necessary technology level.

      There’s nothing inherently problematic in the idea, it’s just very big and ambitious. Equally we have no reason to believe that mega structures are not possible, you throw enough resources and science at the problem. FTL on the other hand has real physical restrictions against its existence, we have no reason to believe those restrictions can be overcome.

      Dyson spheres are just very very big, no new crazy negative energy, subspace conduits required, just brute force engineering.

      • Uriel238 [all pronouns]@lemmy.blahaj.zone
        2·
        6 months ago

        True! Long-term travel within the heliosphere is still thwarted due to the radiation of CMEs which require 350cm of concrete for protection. (Our manned trips to the moon were timed during solar minimum, and still had some worrying moments). While a moon base would could be accomplished by putting it underground (or having shelters underground at minimum) it still keeps us from getting to Mars.

        Then there’s the matter of creating a self-sustained ecology. All of our efforts so far have either died off or required infusions of elements to perpetrate. Also only a matter of time before we work out a configurable system.

        But both of these are something like nuclear fusion, in that we know it can actually be done because we have natural examples (even if self-sustaining nuclear fusion only exists in the core of a star, we’re pretty sure it happens IRL). We don’t have signs of FTL or megastructures that don’t collapse into a giant ball of mass. To qualify for a megastructure, we’d simply have to create something that is millions of meters. Our current freestanding structures measure in the hundreds of meters, and we have at most a few kilostructures like the LHC (27KM) which depends a lot on its fixture to the earth.

        So yeah, it’s a matter of developing the technology, but I suspect there are a lot fewer decades and great filters between when we figure out surviving CMEs in space versus building megastructures in space that don’t collapse.

    • neo@feddit.de
      83·
      6 months ago

      In the Kardashev Scale, a Type II Civilization would build a Dyson Sphere

      I know there’s an methodical thought process behind those things, but mhh… this feels more fiction than science to me.

      I’m fine with research, but I’m worried some might use it as a slippery slope into pseudo science.

      • Echo Dot@feddit.uk
        4·
        6 months ago

        I don’t think there’s any real risk of that. The media often like to overhype scientific inquiries but all they’re doing is looking at existing data

  • Gimpydude@lemmynsfw.comEnglish
    181·
    6 months ago

    A Ringworld would be more likely than a Dyson sphere, the mass requirements are so much lower.

  • CRUMBGRABBER@lemm.eeEnglish
    141·
    6 months ago

    As an owner of three private for profit Dyson spheres, I strongly disapprove.

  • nyctre@lemmy.world
    101·
    6 months ago

    Let’s say we detect one in some other galaxy. What then? And how do you reach out to them?

      • GladiusB@lemmy.world
        1·
        6 months ago

        IF (and that’s a big if) it would lead to clues how to build one. And we could direct communications precisely at it and hope for something to come back.

    • Demuniac@lemmy.world
      6·
      6 months ago

      Well if we find one we have proof of advanced life elsewhere in the universe. That’s the most important thing. Reaching out will take millions of years.