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### Would someone be able to see where they are headed once they crossed the event horizon? [duplicate]

Let us say an explorer was studying a supermassive black hole and ended up blundering past the event horizon. From my understanding, which may be wrong, the only paths allowed after crossing the event ...
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### How can anything ever fall into a black hole as seen from an outside observer?

The event horizon of a black hole is where gravity is such that not even light can escape. This is also the point I understand that according to Einstein time dilation will be infinite for a far-away-...
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### Why is a black hole black?

In general relativity (ignoring Hawking radiation), why is a black hole black? Why nothing, not even light, can escape from inside a black hole? To make the question simpler, say, why is a ...
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### Do virtual particles actually physically exist?

I have heard virtual particles pop in and out of existence all the time, most notable being the pairs that pop out beside black holes and while one gets pulled away. But wouldn't this actually violate ...
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### Will an object always fall at an infinite speed in a black hole? [duplicate]

Most of you if not everybody will agree that the stronger the gravitational pull, the faster an object will fall. For example, on a planet with 50 times the gravity of Earth, any object will hit the ...
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### How Are Galaxies Receding Faster Than Light Visible To Observers?

We know that some galaxies are moving away from us faster than the speed of light and we know it by measuring the redshift, but how's that possible? If they're moving away say at $2c$, how would the ...
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### Would the inside of a black hole be like a giant mirror?

As any light reflected or emitted from objects inside a black hole (if it is possible to be there) does not leave the event horizon and comes back inside, would it be like seeing yourself? What I ...
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### Does the radio (between two co-moving astronauts) stop working when crossing the event horizon?

There are a lot of questions about crossing the EH (event horizon) of a black hole on this site. Some of them suggest, that when you cross the horizon, nothing special happens, you don't even notice ...
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### Taking selfies while falling, would you be able to notice a horizon before hitting a singularity?

I am generally interested in the role of "pings"(0a) between participants (a.k.a. "signal roundtrips"(0b), as familiar for instance from Synge's "five point curvature detector") in the determination ...
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### Why doesn't the light get out?

You're standing on a gedanken planet holding a laser pointer straight up. The light doesn't curve round, or slow down as it ascends, or fall down. It goes straight up. Now I wave my magic gedanken ...
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### How does the speed of light vary throughout a black hole?

I surmise that there is no equation defining the speed of light, as there is with the speed of sound. Presumably, we assume that, at the event horizon, it falls to zero. What is its value at the ...
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### What happens 'inside' the event horizon of a black hole, in particular to photon speed

This is a follow-up question to two answers given here and here, where the speed in different coordinate systems is discussed when approaching the Schwarzschild radius. To cite, derived directly from ...
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### Do photon inside event horizon exceeds speed of light? [closed]

Event horizon is a region of space whereby nothing with information can escape, so I imagine that a photon falls into this region of space does it accelerates toward the singularity if it exists? Do ...
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### Given the 1st Postulate of SR, doesn't the 2nd Postulate go without saying? [duplicate]

i've been looking over possible duplicates of this question and haven't found one yet. so, using Wikipedia as the textual source: The Principle of Relativity – The laws by which the states of ...
In the Newtonian description of a black hole, it is a gravitating astrophysical object for which the escape velocity exceeds the speed of light in vacuum ($c$). But what does this actually mean for a ...