So I learned about the Schwartzchild radius, which is the radius of an object's event horizon. But how we define an event horizon is that it's a region of space where the gravitational acceleration light could not escape it. And according to Einstein no information can travel faster than light, therefore no information can escape from within a black hole, so how come we be able to observe a property of the singularity: its mass?
According to Schwartzchild's equations we can deduct the mass of a black hole from an observable property, which is the radius of its event horizon of course.
Furthermore, gravity only travels at the speed of causality/light, for instance if the sun disappeared we would continue orbiting it for 8 minutes until the deformed space-time comes back to normal, so how come any object outside of the black hole even know there is gravitational pull in that region of space?
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Qmechanic
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