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TED talk: Tabby talks about her star. (2016) https://www.ted.com/talks/tabetha_boyajian_the_most_mysterious_star_in_the_universe https://www.ted.com/talks/tabet

TED talk: Tabby talks about her star. (2016) https://www.ted.com/talks/tabetha_boyajian_the_most_mysterious_star_in_the_universe https://www.ted.com/talks/tabetha_boyajian_the_most_mysterio... Something massive, with roughly 1,000 times the area of Earth, is blocking the light coming from a distant star known as KIC 8462852, and nobody is quite sure what it is. As astronomer Tabetha Boyajian investigated this perplexing celestial object, a colleague suggested something unusual: Could it be an alien-built megastructure? Such an extraordinary idea would require extraordinary evidence. In this talk, Boyajian gives us a look at how scientists search for and test hypotheses when faced with the unknown.

mojomark 5y ago
"It has also been hypothesized that the changes in brightness could be signs of activity associated with intelligent extraterrestrial life constructing a Dyson swarm; however, further analysis based on data through the end of 2017 showed wavelength-dependent dimming consistent with dust but not an opaque object such as an alien megastructure, which would block all wavelengths of light equally.[17][9][19]" Fun, to think about, and who's to say the Dyson Sphere isn't somehow transluscent, but this sounds like pretty good evidence to my pea brain that we're observing a non-Dyson Sphere object. Definitely exciting candidate target though and I'm happy we keep searching for our celestial cousins.
- intrepidhero 5y ago
  I was confused by that statement and the sibling comment that a Dyson swarm would block visible light but not IR and Tabby's star seems to dim in IR. So is it dimming all wavelengths or not? Is it dimming some visible (but not all) and IR?
  - marcosdumay 5y ago
    > would block visible light but not IR It would not block some spectrum of IR, probably at the far IR region. Compared to a star, it should probably emit much less near visible IR. It depends on what temperature the aliens prefer, but I wouldn't expect anything similar to a star's emissions. Anyway, there exist telescopes tuned to far IR. I don't know what kind was used on that observation.
  - MattPalmer1086 5y ago
    It's not that it wouldn't block IR from the star. It's that they would radiate waste heat as IR.
- robbomacrae 5y ago
  Unless the dark forest [0] theory is correct and the Dyson Sphere is designed to look to all intents and purposes like a dust cloud.. (not that it helps us with our discovering). 0: https://en.wikipedia.org/wiki/The_Dark_Forest https://en.wikipedia.org/wiki/The_Dark_Forest
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 ago
  Forgive 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 ago
    There 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 ago
      That 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.

mojomark 5y ago

"It has also been hypothesized that the changes in brightness could be signs of activity associated with intelligent extraterrestrial life constructing a Dyson swarm; however, further analysis based on data through the end of 2017 showed wavelength-dependent dimming consistent with dust but not an opaque object such as an alien megastructure, which would block all wavelengths of light equally.[17][9][19]" Fun, to think about, and who's to say the Dyson Sphere isn't somehow transluscent, but this sounds like pretty good evidence to my pea brain that we're observing a non-Dyson Sphere object. Definitely exciting candidate target though and I'm happy we keep searching for our celestial cousins.

intrepidhero 5y ago
I was confused by that statement and the sibling comment that a Dyson swarm would block visible light but not IR and Tabby's star seems to dim in IR. So is it dimming all wavelengths or not? Is it dimming some visible (but not all) and IR?
- marcosdumay 5y ago
  > would block visible light but not IR It would not block some spectrum of IR, probably at the far IR region. Compared to a star, it should probably emit much less near visible IR. It depends on what temperature the aliens prefer, but I wouldn't expect anything similar to a star's emissions. Anyway, there exist telescopes tuned to far IR. I don't know what kind was used on that observation.
- MattPalmer1086 5y ago
  It's not that it wouldn't block IR from the star. It's that they would radiate waste heat as IR.
robbomacrae 5y ago
Unless the dark forest [0] theory is correct and the Dyson Sphere is designed to look to all intents and purposes like a dust cloud.. (not that it helps us with our discovering). 0: https://en.wikipedia.org/wiki/The_Dark_Forest https://en.wikipedia.org/wiki/The_Dark_Forest

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 ago
Forgive 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 ago
  There 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 ago
    That 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.