WorstMedivhKR
WorstMedivhKR t1_j2e2ko9 wrote
Reply to comment by Cyoarp in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
Ok, that's correct, but still from either observer's perspective the other person is not traveling faster than the speed of light, due to relativity it is very different. It is true that they won't see each other though even if they enter at the same time, so long as the entry point is different, for reasons I don't really understand mathematically since I haven't actually taken GR but have to do with the geometry of the black hole and that the singularity doesn't actually appear small, it appears to grow larger and larger as you approach it paradoxically. So it's more like free falling onto a huge black planet would look like.
https://jila.colorado.edu/~ajsh/insidebh/schw.html
> Geometrical intuition, bolstered by pictures like this one would suggest that the center of the Schwarzschild black hole is a point. That intuition is misleading. If you and a friend fall into a black hole at the same time but at different locations (in latitude and longitude), you do not approach each other as you approach the singularity. Rather, the diverging tidal force channels the parts of your body along the inward radial direction. Far from meeting your friend at the singularity, you cannot even put out your arms to touch her.
> “The” singularity is not a point. Rather, it is a 3-dimensional spatial boundary where general relativity commits suicide. New physics, presumably quantum gravity in some form, must replace general relativity at singularities. What that new physics is remains a profound unanswered question.
WorstMedivhKR t1_j2dsjjw wrote
Reply to comment by graveybrains in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
You will eventually be spaghettified regardless. In a large enough black hole it's after you cross the event horizon but before hitting the singularity.
WorstMedivhKR t1_j2aqomj wrote
Reply to comment by Paradox68 in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
No, you can see ahead of you everything that fell in before you, because it's all time dilated and "frozen" as it approaches the singularity.
WorstMedivhKR t1_j2aql5g wrote
Reply to comment by DanishWeddingCookie in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
No, time does not stop on crossing the event horizon. The view of the external universe above actually speeds up.
WorstMedivhKR t1_j2apvf8 wrote
Reply to comment by Cyoarp in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
> If two objects are moving near the speed of light and they happen to be moving in opposite directions then they are moving towards each other at faster than the speed of light.
That's not correct. https://en.wikipedia.org/wiki/Velocity-addition_formula
WorstMedivhKR t1_j2apghs wrote
Reply to comment by Xethinus in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
This is what actually falling into a simple Schwarzschild black hole would look like. The physicist behind this, Andrew Hamilton, also has some for more realistic types of black holes but they are harder to understand. Notice that locally nothing special happens when crossing the "true" event horizon, and there is still an outside view of the universe. The only way you get a tunnel effect upward with darkness in every other direction is if you use a great deal of energy just outside the true event horizon to accelerate against the gravity of the black hole.
The ending of this video is hitting the singularity.
WorstMedivhKR t1_j2ap0bt wrote
Reply to comment by Careless_Implement12 in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
That's not true, you never locally exceed the speed of light pre-singularity in a black hole. You also don't notice anything special when crossing the event horizon, there is always an apparent event horizon ahead of you even when you have crossed the "true" event horizon already.
WorstMedivhKR t1_j2amk4i wrote
Reply to comment by graveybrains in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
You'd be spaghettified and die long before the evaporation of the black hole or hitting the singularity or the end of the universe.
WorstMedivhKR t1_j2amc26 wrote
Reply to comment by Ryunah in What is our current "best guess" about how to observers that entered a black hole on opposite sides would look to each other once they crossed the event horizon? by WittyUnwittingly
That's what it looks like to a distant external observer. Except even then the person gets redshifted to invisibility pretty quickly. If you're inside time still passes "normally" locally.
WorstMedivhKR t1_jdlyf4c wrote
Reply to comment by Axial-Precession in If earth was a smooth sphere, which direction would water flow when placed on the surface? by Axial-Precession
Egypt is higher than sea level, therefore it runs south to north.