The largest Black Hole compared to Our Solar System

  • octoperson@sh.itjust.works
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    1 year ago

    And it has a density of only about 3g per cubic meter. It’s not much denser than a vacuum made with a mechanical pump.

    • jballs@sh.itjust.works
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      1 year ago

      That’s the thing about black holes that always blows my mind. I don’t understand how the larger a black hole is, the less dense that it is. In my mind, I always think of black holes as super dense objects containing so much matter in such a little space that the gravity is crazy strong. How can something so not dense be a black hole? It doesn’t make sense to me!

      • TauZero@mander.xyz
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        1 year ago

        To be fair, the density is calculated from the event horizon, which is a somewhat arbitrary boundary. All the mass is still concentrated at the singularity which is still infinitely dense, just… a bit more so.

        • jballs@sh.itjust.works
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          1 year ago

          Ah, I didn’t realize that. I guess that’s a little more terrifying. Sounds like you could pass the event horizon and not be instantly crushed, but would have no way of ever escaping. You’d just eventually get sucked into the singularity.

      • octoperson@sh.itjust.works
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        1 year ago

        Not really. If more material falls in, its mass and size increases (the volume increases faster than the mass, which is why it’s so unexpectedly low density in the first place), but otherwise it just sort of sits there.

        Over the very long term, it will evaporate away by Hawking radiation. But that’s a very very slow process. Like, long after everything else in the universe has ended.

  • Che Banana@lemmy.ml
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    1 year ago

    Is there a banana for scale or does Lemmy use a different model for scale? Beans?

  • Flying Squid@mander.xyz
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    1 year ago

    That’s actually smaller than I would have thought. I wouldn’t have expected our solar system to even be visible in comparison.

    • jon@lemdro.id
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      1 year ago

      Normally black holes are considered to be everything up to the event horizon. E.g., from the Wikipedia page:

      The size of a black hole, as determined by the radius of the event horizon, or Schwarzschild radius, is proportional to the mass, M

      The term “black hole” derives from the fact that beyond a certain point light can’t escape, that point being the event horizon.