Comment on An alien who sees in the radio part of the light spectrum would probably be blinded by all our wireless communications

roguetrick@lemmy.world ⁨1⁩ ⁨month⁩ ago

• XeroxCool@lemmy.world ⁨1⁩ ⁨month⁩ ago

  I don’t see why they’d have to have big eyes. We use massive radio telescopes for sensitivity, not for the spectrum range. AM radio is in the order of 100 meter wavelengths, but handheld devices can receive it. Wavelength isn’t really the defining factor as much as being able to handle the frequency of the data over the time required. Wavelength is not how tall the wave is, amplitude is.

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  • roguetrick@lemmy.world ⁨1⁩ ⁨month⁩ ago

    Handheld devices can receive it, but to actually “see” with it you need a very large apature and a “retina” with many of those antennas. The overall structure of an eye capable of seeing would be massive, not because the signal is faint but because that’s what you need for acuity to actually resolve things. For something like AM, we’re talking a very big structure.

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    • XeroxCool@lemmy.world ⁨1⁩ ⁨month⁩ ago

      I realize now I was thinking of data in the time axis rather than the width/resolution direction

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  • Natanael@infosec.pub ⁨1⁩ ⁨month⁩ ago

    Massive singular radio telescopes are used to pick up individual signals from one direction, and can’t do imaging alone.

    Sure you can pick up long wave radio with smaller antennas, but not without trade-offs. They often need long coils, and to make up the remaining difference you need to very precisely control electric resonance, and you lose efficiency (you pick up less energy from the radio waves). You definitely can’t do imaging with just one.

    Just look at how big NFC and Qi coils are, they can’t practically be made smaller at those wavelengths, or else you lose too much energy!

    Massive radio telescope arrays spanning the globe uses the massive distance to create a tiny amount of angular resolution, just enough that with months of processing you can image a black hole a few light years away with some thousands of pixels. Compare to how your phone can run deblur algorithms on a fraction of the power over far more pixels, because the angular resolution makes such a huge difference (blur radius is infinitely smaller)

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    • XeroxCool@lemmy.world ⁨1⁩ ⁨month⁩ ago

      Alright, I think I can see I was picturing data in the wrong dimension. The data for an AM radio, in a very human-like interpretation, is running along the time axis rather than actual width across the available sources. It’d take multiple radios to “see” multiple frequencies.

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• vala@lemmy.world ⁨1⁩ ⁨month⁩ ago

  Biblically accurate angels have entered the chat

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• lolcatnip@reddthat.com ⁨1⁩ ⁨month⁩ ago

  You’ve described the reasons why aliens that see in the radio spectrum would never evolve in the first place. Aliens from a particularly cool star might have their vision attuned to infrared, but no place that’s warm enough to have liquid water would be cold enough to make radio waves more useful than infrared.

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  • roguetrick@lemmy.world ⁨1⁩ ⁨month⁩ ago

    Yeah and even functional infrared eyes need to be at least twice the size of ours. Anime eyes

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    • lolcatnip@reddthat.com ⁨1⁩ ⁨month⁩ ago

      Larger than they would be due visible light, yes, but not necessarily larger than human eyes. Birds, for instance, can have amazing vision with much smaller eyes.

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