• Sam_Bass@lemmy.world
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    5 days ago

    Everything in the universe reflects light. Except black holes. Only things you cannot see do not reflect light.

    • Deme@sopuli.xyz
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      4 days ago

      The event horizon isn’t a physical object. Does a singularity reflect light? (I’m guessing it’s still a no)

      • TachyonTele@lemm.ee
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        4 days ago

        Once something moves past the horizon any light that bounced off it would be pulled towards the center with it. Effectively making it non reflective. It’s possible all the energy from being crushed into a singularity causes a glow around it, like the disk around the outer area of a black hole.

        If that’s the case, the glow itself would also be sucked immediately into the singularity. Maybe for the shortest of time, on the tiniest plank scale, the singularity produces light.

        • ikidd@lemmy.world
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          4 days ago

          The accretion disk would emit light as particles were accelerated into the hole. Plus there would be hawking radiation from the evaporative process black holes have.

        • cows_are_underrated@feddit.org
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          4 days ago

          The only form of “light” (it isn’t really light but radiation, which I’d basically the same as light just that it has a different energy value etc) is the hawking radiation.

        • Deme@sopuli.xyz
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          4 days ago

          The event horizon only obscures objects that are inside it, it has nothing to do with reflectivity of the object itself.

          An observer situated between the singularity and an object within the event horizon could still intercept the light reflected from said object.

          • TachyonTele@lemm.ee
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            4 days ago

            Light bouncing of an object is what creates reflection. The only way to see reflection past the horizon is to be closer to the singularity than the object you’re looking at.

            • Deme@sopuli.xyz
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              4 days ago

              That is what I said, yes.

              The point being that the event horizon deals with the structure of spacetime, while reflectivity is a material property. An object doesn’t get painted with vantablack when it passes the event horizon.

        • Deme@sopuli.xyz
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          4 days ago

          No. An object within the event horizon is still reflecting light just as it was before falling in. The only difference is in relation to where that reflected light can or cannot go from there.

      • Sam_Bass@lemmy.world
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        4 days ago

        Never seen a singularity so would have to agree it doesn’t. Visible Event Horizons are made up of matter that does reflect light, but if there is no matter involved only light you would likely see is distorted as it passes through it from other sources

        • Deme@sopuli.xyz
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          4 days ago

          No event horizon is made up of matter. Do you mean the matter around and behind the black hole, by which the location and size of the black hole can be inferred?

    • Swedneck@discuss.tchncs.de
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      4 days ago

      except you can still arguably see things that don’t reflect light, if you were anywhere near a black hole (let’s imagine it has no accretion disk and thus isn’t surrounded by a bunch of light) it’d be pretty obvious what with the bending of light and how it’s a disk of pure blackness against the backdrop of stars.