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I actually believe that if we detect spacefaring aliens, it will actually be from events like this. There's a lot of thought that has gone into this. Basically,
by cletus 5y ago
I actually believe that if we detect spacefaring aliens, it will actually be from events like this. There's a lot of thought that has gone into this. Basically, a natural evolution seems to be to build Dyson Swarms. There are lots of reasons for this, most notably the efficiency in creating living area (per unit mass) compared to planets and the "free" energy.
A consequence of this is such a megastructure would have high IR emissions. Why? Because in space the only way to cool off is to radiate heat away. That wavelength of that radiated heat is determined by the temperature of the radiating object. For any normal temperature we'd expect to see, that means IR radiation.
The Tabby's Star dimmings seem to have the opposite behaviour: very low IR emissions. This is a pretty strong suggestion that it isn't artificial in origin.
- robbomacrae 5y agoForgive me for asking a potentially silly question, but wouldn't the heat dissipating via IR be also seen as wasted energy? I understand that at our current level of physics, to do anything less would involve catastrophic heat build up but I would suspect an alien species capable of building a Dyson Swarm to have access to other means of keeping the temperature stable whilst leaving very little energy to go to waste.
- contravariant 5y agoThere are thermodynamic limits to how efficient solar energy can be. It's almost inevitable that a sizeable portion of the energy will get lost as heat.
- Hallucinaut 5y agoThat may be the case, but why would it radiate on the non-star facing side? Take the JWT for example: no-one looking back at that would see anything higher than -50 degrees Celsius. If the point was to capture energy then anything radiating from the non-star facing side suggests inefficiency. Even if the solar energy has limits, why wouldn't they use waste heat to support, say, plant growth? Not that I think it is a mega-structure, it's just it doesn't strike me as lack of IR emissions as being that informative.
- contravariant 5y agoThe JWT is a perfectly good example of this, it's not hot compared to the sun but it's way hotter than the cosmic background. And that's if you're just reflecting light back to the sun, when you try to extract meaningful work from it you'll have to absorb a lot more energy.
- deleted 5y ago[deleted]
- MattPalmer1086 5y agoDoes it suggest a natural origin, or just that it isn't likely to be a Dyson swarm?
- hotpotamus 5y agoMy favorite example of how an alien civilization could send signals out to the neighborhood is just to put a really big triangle in orbit around their star. Anyone monitoring the brightness of the star for planets would get a real surprise by the signature it puts in their data.