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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 misconceptio
by orlp 2y ago
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.
- elashri 2y agoI 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.