Comment on Scientists confirm that the first black hole ever imaged is actually spinning

AbouBenAdhem@lemmy.world ⁨1⁩ ⁨year⁩ ago

• hotdaniel@lemmy.zip ⁨1⁩ ⁨year⁩ ago

  Does the black hole spin? Or does the stuff outside the black hole spin? 🤔

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  • AbouBenAdhem@lemmy.world ⁨1⁩ ⁨year⁩ ago

    The black hole and the stuff outside it constitute a single system, and within that system, angular momentum is conserved. So as objects cross the event horizon, their angular momentum is transferred to the black hole.

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    • hotdaniel@lemmy.zip ⁨1⁩ ⁨year⁩ ago

      Well… does it? If all the stuff falls in and only the volume remains, who could say that it’s spinning? How could you detect it?

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      • AbouBenAdhem@lemmy.world ⁨1⁩ ⁨year⁩ ago

        For one thing, the size and shape of the event horizon changes depending on the black hole’s spin.

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      • Fungah@lemmy.world ⁨1⁩ ⁨year⁩ ago

        I thought nothing actually crossed the event horizon and was essentially frozen approaching a complete stop in time in a kind of 2f representation of 3d reality until it slowly leaked out trillions of years later as hawking radiation?

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  • scarabic@lemmy.world ⁨1⁩ ⁨year⁩ ago

    Isn’t most everything spinning? Seems like having zero angular momentum would be rare and remarkable. I’m not even sure how exactly to define zero momentum in terms of reference frames.

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  • tdawg@lemmy.world ⁨1⁩ ⁨year⁩ ago

    If you’re asking that then you first need to ask what the distinction between the two is. and further does it even make sense for one to spin and not the other

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    • NewNewAccount@lemmy.world ⁨1⁩ ⁨year⁩ ago

      Is there not a distinction? I assume the singularity at its center has different properties than the matter outside of that point.

      Note: I have a rudimentary understanding of what black holes and their components are.

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      • Telodzrum@lemmy.world ⁨1⁩ ⁨year⁩ ago

        Even if there is heterogeneity inside the system, that does not indicate severability or that the whole system is made up of smaller constituent systems.

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  • KidsTryThisAtHome@lemm.ee ⁨1⁩ ⁨year⁩ ago

    It’s in space and everything is relative, how do we know *everything else" isn’t just spinning around the black hole? 🤔

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    • Devion@feddit.nl ⁨1⁩ ⁨year⁩ ago

      Because that would require a centripetal force on everything else, which obviously isn’t the case.

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  • sleep_deprived@lemmy.world ⁨1⁩ ⁨year⁩ ago

    Yes.

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• moistclump@lemmy.world ⁨1⁩ ⁨year⁩ ago

  Can you ELI5 relativistic frame dragging and process?

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