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There are many Q&As about whether something inside a black hole can escape the event horizon if another massive object gets close enough to pull it out. I realize the answer (I think universally agreed?) is no because the geometry inside the horizon simply allows for no paths leading out of it.

A follow up to that question which I haven't seen addressed is whether gravity from an object outside the black hole - say a binary twin that is either also a black hole or just shy of it - affects the spacetime geometry inside the black hole, and thus the objects inside, in any way.

For example, suppose you're freefalling inside an SMBH and another massive object (maybe a black hole, maybe not, but I think it shouldn't matter) is in a stable orbit and not on a path to merge with the one you're in. Do you feel the pull of the external object and how does that impact your inevitable journey to the singularity? Is there any configuration that could pull you back toward the horizon (even if you can't cross it?) Will it simply slow you down but never cause you to reverse your path (a form of time dilation almost)?

A Penrose diagram or animation illustrating how the internal geometry of the black hole changes as another supermassive object nears it would - if available - likely be extremely helpful. I think I can imagine one but am definitely not qualified to try to create it and wouldn't know if it was accurate.

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    $\begingroup$ Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on Physics Meta, or in Physics Chat. Comments continuing discussion may be removed. $\endgroup$
    – Buzz ♦
    Commented Jun 3 at 21:37

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They are not affected. Any black hole behaves like if all its mass was located in its center or on the shell of its surface.

Thus, it is impossible to transfer information from inside the black hole or into black hole by gravity waves or by moving or rotating massive objects.

In fact, there is no information inside a black hole, otherwise it would contradict quantum mechanics.

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    $\begingroup$ This is not true with dynamical black holes; when they are forming (or merging), black holes are not spherical. Thus, your answer doesn't really make much sense. $\endgroup$
    – Peter Shor
    Commented Jun 2 at 20:44
  • $\begingroup$ @PeterShor I was not talking exclusively about spherical black holes. Rotating, non-spherical black holes behave as if their mass still was at the center but was rotating. Or if it was distributed over surface ellipsoid. $\endgroup$
    – Anixx
    Commented Jun 2 at 20:46
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    $\begingroup$ if two black holes are merging, they don't behave as if the mass was all at the center. That would mean that there's an instantaneous change from two spherical black holes to one spherical black hole. That's not true ... it's a gradual change (fairly fast, but still gradual). $\endgroup$
    – Peter Shor
    Commented Jun 2 at 20:48
  • $\begingroup$ @PeterShor well, yes. You are right. When two black holes are merging or in other non-equilibrium scenarios, their surface forms are not spherical or ellipsoidal and can theoretically have any form. But their gravitational field is fully determined by the form of their surface. $\endgroup$
    – Anixx
    Commented Jun 2 at 20:50
  • $\begingroup$ @PeterShor The horizon of any shape is the spatial center of the black hole since any inward interval from the horizon is causal. A black hole does not have a “center” inside the horizon, because (in the Schwarzschild case) $r=0$ is the equation of an infinitely long spacelike line, not a point. In case of rotation or charge, this line is replaced by the infinitely long hyper-cylinder of the inner horizon, spacelike along and null across. $\endgroup$
    – safesphere
    Commented Jun 3 at 4:36

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