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Astronomy

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    $\begingroup$ What do you mean by "surrounded by accretion disks"? $\endgroup$
    – PM 2Ring
    Commented Sep 16, 2019 at 11:09
  • $\begingroup$ That enough be around the black hole that the number direct paths (not intersecting a disk) between the event horizon and the observer is low or zero. That is assuming that intersecting disks can exist for long enough to be noticed before interfering with each other. (and enough are being formed that more than one even happens at the same time.) No idea how much of my understanding is just geometry that's completely wrong at this scale. $\endgroup$
    – bobsburner
    Commented Sep 16, 2019 at 11:14
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    $\begingroup$ Accretion disks are a bit like the rings of Saturn. They rotate in the black hole's equatorial plane, so you can't really have 2 intersecting accretion disks like that. Also, unlike Newtonian gravity, where you can have orbits in pretty much any plane, orbits around a rotating BH are strongly constrained. Even stuff that approaches the BH from a weird angle gets forced into an equatorial orbit because of frame dragging. $\endgroup$
    – PM 2Ring
    Commented Sep 16, 2019 at 11:39
  • $\begingroup$ You make a good point. How long should it take for everything to get pulled into line with the equatorial plane? If I think of a decent way to phrase it, I'll edit my answer. Feel free, if anyone thinks they can improve it. $\endgroup$
    – bobsburner
    Commented Sep 16, 2019 at 11:55
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    $\begingroup$ With black holes, "How long?" questions are tricky, due to time dilation, so processes look slower to distant observers. But in the time frame of bodies falling towards the BH, stuff happens pretty quickly, since everything's moving at relativistic speeds. Not everything that falls towards the BH gets pulled inside the event horizon. It can get deflected into a hyperbolic trajectory. Or it can collide with matter in the accretion disk. Such collisions are extremely violent, and tend to eject a fair bit of "shrapnel", some of that may be thrown out in jets by the disk's powerful magnetic field. $\endgroup$
    – PM 2Ring
    Commented Sep 16, 2019 at 12:11