# Tag Info

Accepted

### Can you exit the event horizon with a rocket?

It is often said that the escape velocity at the event horizon is the speed of light, but while this is true in a sense it is not very useful. The problem is that the speed is an observer dependent ...
• 358k

### Why is light bent but not accelerated?

You missed a key aspect of general relativity (GR): The gravitational 'force' we observe is an illusion according to general relativity. Specifically, the 'gravitational force' and 'gravitational ...
• 1,774
Accepted

### How do I interpret uncertainty in velocity greater than the speed of light?

The right formula is $$\Delta X \Delta P \geq h/4\pi$$ where $P$ is the momentum which is approximatively $mv$ only for small velocities $v$ when compared with $c$. Otherwise you have to use the ...
• 74.8k
Accepted

### Why is light bent but not accelerated?

One thing that the previous answers are missing -- the light is accelerated; it just is accelerated according to the rules of special relativity, which says that it cannot pick up speed when already ...
• 41.7k
Accepted

### Indirectly breaking the speed of light

A black hole of mass $10^{36}$ kg would have a Schwarzschild radius (the distance from the center to the event horizon) of about $1.5\times 10^{9}$ m. So your choice of "orbital" distance is ...

### Why do the neutrinos (with mass) from a supernova arrive before the light (no mass)?

The situation with supernova is not about speed of flight but about time of emergence. A type IIa supernova candidate is big, even with the vastly powerful explosion of the core it takes hours to blow ...
Accepted

### Since the speed of light is constant and also the speed limit; would you, in your reference frame, have no upper bound on your speed?

You know this is now your speed because you have a speedometer telling you so. This is precisely where you hit a (metaphorical) roadblock. A speedometer must use something outside of your reference ...
• 7,698
Accepted

### Can the increase in thickness of a piece of paper which can be folded infinitely surpass the speed of light?

No, you can't, for a couple of different reasons. The first is the difficulty of folding paper more than a few times. Mythbusters managed to fold one sheet 11 times I think, using a very large sheet ...
• 34.4k
Accepted

### Super Fast Message

Good question! Imagine sweeping the bat signal really quickly across Mars. You could totally have it move faster than the speed of light across the surface! But now imagine that you are standing on ...
• 12k
Accepted

### Space falling faster than light after it falls inside the event horizon of a black hole?

This is the "river" picture of black holes, as Dale said, but I disagree strongly with his statement that it is a "nice heuristic". Rivers flow at a certain speed. If you fall into ...
• 27.7k
Accepted

### Why didn't Lorentz conclude that no object can go faster than light?

If I had to sum up my findings in a sound bite it would be this: Einstein was the first to derive the Lorentz transformation laws based on physical principles--namely that the speed of light is ...
• 4,800

### Why can't we break the speed of light in vacuum?

The article you linked is about a false alarm that was caused by some error in data processing. The neutrinos didn't go faster than light. The popular media of course blew this out of proportion, as ...
• 6,614