Lightspeed Barrier And Black Holes

[Photon Guy]

Once you cross over the event horizon of a black hole you cross the point of no return. The speed of light is 186,000 MPS but once you cross over the event horizon you would have to have a speed faster than that to escape from the gravity of the black hole and nothing can move faster than 186,000 MPS because as weight increases with speed, once you reach that speed your weight becomes infinite so it would require infinite energy just to reach light speed. That is why you can't escape from a black hole since the escape speed is faster than the speed of light and you can't go faster than the speed of light according to conventional physics. 

Anyway, I was thinking, if you could somehow increase your speed beyond the speed of light, lets say you could go at 200,000 MPS, even though physics says you can't lets say you can, could you, at least in principle, escape from within the event horizon of a black hole?

[Strange]

2 minutes ago, Photon Guy said:

Once you cross over the event horizon of a black hole you cross the point of no return. The speed of light is 186,000 MPS but once you cross over the event horizon you would have to have a speed faster than that to escape from the gravity of the black hole and nothing can move faster than 186,000 MPS because as weight increases with speed, once you reach that speed your weight becomes infinite so it would require infinite energy just to reach light speed. That is why you can't escape from a black hole since the escape speed is faster than the speed of light and you can't go faster than the speed of light according to conventional physics. 

Although it is often explained that way, that is not the reason you can't escape a black hole(*). After all, you can temporarily leave the surface of the Earth at less than the escape velocity. But you can't leave a black hole, even temporarily.

It is better to think of it as being due to space time curvature: after you pass the even horizon, spacetime is so curved that there are no paths that lead away from the centre of the black hole. Whatever direction you go is towards the centre. Worse, spacetime is so curved that "towards the centre" is no longer a spatial direction but is your future. And there is no escaping the future

 

(*) Actually, I suppose that in Guilstand-Painleve coordinates it is true. 

[Strange]

Here is a nice illustration of how you can view space as "falling" into a black hole (taking things with it). It reaches the speed of light at the event horizon, which is consistent with the description in the first post: https://jila.colorado.edu/~ajsh/insidebh/waterfall.html

[MigL]

So you are essentially saying, if you can do an impossibility, you can do other impossibilities.
Makes perfect sense, but doesn't really add any new insights.

[Photon Guy]

So concerning black holes, my advice, don't go near them.

[Phi for All]

34 minutes ago, Photon Guy said:

So concerning black holes, my advice, don't go near them.

We can calculate the innermost stable circular orbit around a particular black hole. 

[MigL]

On ‎7‎/‎9‎/‎2020 at 8:29 AM, Strange said:

It is better to think of it as being due to space time curvature: after you pass the even horizon, spacetime is so curved that there are no paths that lead away from the centre of the black hole. Whatever direction you go is towards the centre. Worse, spacetime is so curved that "towards the centre" is no longer a spatial direction but is your future. And there is no escaping the future

I'm not sure if that's a valid interpretation either.
There may be no time-like paths out of the event horizon, but, as the light cones flip on their side, space-like paths are now available.
For space-like intervals dS^2 = -c^2*dT^2 + dX^2 + dY^2 + dZ^2  is greater than 0 ; IOW,  R^2 > c^2*dT^2.
( normal time-like is dS^2 < 0 and  R^2 < c^2*dT^2 )

So even though there is no 'escaping the future', space-like intervals break causality, and render past/future meaningless.

Edited August 5, 2020 by MigL
formula mistakes

[Markus Hanke]

On 7/9/2020 at 1:21 PM, Photon Guy said:

Anyway, I was thinking, if you could somehow increase your speed beyond the speed of light, lets say you could go at 200,000 MPS, even though physics says you can't lets say you can, could you, at least in principle, escape from within the event horizon of a black hole?

You wouldn't need to escape! Since tachyonic motion is by definition space-like, it will always be possible (given suitable boundary conditions) to find a geodesic that is precisely perpendicular to the local time axis. There then exists at least one observer for whom you are both above and below the event horizon simultaneously.  

Luckily for us, such a thing as a tachyon in all likelihood does not exist, because this would create all manner of awkward issues and problems.

[farcentaurus]

Your mass does not increase as you become relativistic. Assuming you started from Earth, an observer on Earth would measure (I don’t know how) your mass to be increasing. The rocketeer would say the same about Earth as it receded.

[swansont]

13 hours ago, farcentaurus said:

Your mass does not increase as you become relativistic. Assuming you started from Earth, an observer on Earth would measure (I don’t know how) your mass to be increasing. The rocketeer would say the same about Earth as it receded.

Only if you are referring to relativistic mass, which is to say, the total energy — so why not just say the total energy? The mass (rest mass) is the same.