4 ms·
If we are within the event horizon, then the direction towards the center of the black hole is not a spatial direction, but a temporal one. The cental singulari
by gizmo686 5y ago
If we are within the event horizon, then the direction towards the center of the black hole is not a spatial direction, but a temporal one. The cental singularity is in the future.
As it turns out, the temporal direction is the only direction of spacetime which is not symetric. Objects in the future are accelerating faster, which is presisly the prediction you made.
- AnimalMuppet 5y agoIf I understand correctly, if you add up the mass in the universe, the Schwarzchild radius of that mass is 13 billion light years, which is a really interesting number. If we were inside a universe-sized black hole, would we be able to tell? Can we experimentally distinguish a black hole universe from a not-black-hole universe?
- marcyb5st 5y agoGood point! However, inside an event horizon we should have a preferred direction in which all the light cones that can catch up to us actually catch up to us (if Penrose diagrams hold true within an event horizon). That would mean that looking in that direction the universe would appear brighter and given how smooth is the CMB that doesn't seem to happen. It could still work if we assume that when this black hole was created either everything or nothing was causally connected to us. Fascinating point!