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orlp

Again, the no-hair theorem only talks about stationary solutions:

> The no-hair theorem (which is a hypothesis) states that all *stationary* black hole solutions of...

https://en.m.wikipedia.org/wiki/No-hair_theorem

> The field adjustment is instant for the outside observer

And as my above thought experiment shows, any instant changes like such could be used for FTL communication.

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I think time would pass incredibly slowly for an observer that close to the black hole? Since the event horizon provides a singularity where time slows to zero, it makes sense that any non-zero speed along it would go to infinity for an outside observer.

I doubt you could usefully exploit this behavior, because any charges would still need to travel to and away from the black hole at no more than light speed, and because time slows down the further you get to the event horizon the shortest path "around" a black hole would probably not go through it.

What is unique about your thoughts experiment that makes it applies only to dynamical phases?

I am really not getting what you are trying to say?

The point I'm trying to make is that everyone always cites the no hair theorem but completely leaves out the "stationary solution" part, leading to misconceptions. My thought experiment highlights that one can't treat a black hole as a particle that only has mass, charge and angular momentum in a dynamic world, because such a treatment must inherently lead to instantaneous updates to large regions of spacetime in response to 'stimuli' (in the form of mass, charge or angular momentum) for super massive black holes, which is impossible.

I understand that this is valid for stationary solution which is what an astronomical black hole would be most of the time. What I don't get is why do you assume that this would violate causality. In GR the idea that changes must “instantaneously update” large regions of spacetime due to supermassive black holes ignores relativistic effects like time dilation. From the perspective of an external observer, as an object falls into a black hole, time appears to slow down near the event horizon. The infalling object’s influence on the black hole’s external field (e.g., its charge or mass) is perceived gradually by distant observers.

For supermassive black holes, this process might seem slow due to the massive scale of spacetime curvature near the event horizon, but there is no requirement for instantaneous changes. In fact, relativistic causality ensures that no information can propagate faster than light, so updates to the black hole’s charge, mass, or angular momentum are constrained by the speed at which signals (gravitational or electromagnetic) can travel.

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