Speed of Light question

[Umbran]

So that way you can end up with black holes that trap all particles except gravitons.

That doesn't work - if the gravitons travel in those other dimensions, gravity does. And that's what'd keeping things from escaping. There is no "back door" out of a black hole into our normal space.

There's a simpler answer - the statement "nothing can escape a black hole" is true, but insufficiently detailed to give us what we need. In full, the statement is "nothing can escape from within the event horizon of a black hole.

In effect, all you need is that the gravitons be emitted from the outside of the surface, rather than from the interior, and all is well.

 

[Cowpanzamie]

....

 

[Cowpanzamie]

You're all nuts. In the movie The Black Hole the spaceship travels RIGHT THROUGH a black hole! How come none of you have mentioned that, if you're all so smart?

 

[Chainsaw Mage]

You're all nuts. In the movie The Black Hole the spaceship travels RIGHT THROUGH a black hole! How come none of you have mentioned that, if you're all so smart?

Don't forget Star Trek. The Enterprise can travel at *several times* the speed of light. Utter nonsense to say that nothing can go faster than the speed of light. IF any of you doubt it, I'll be glad to lend you my old Wrath of Khan tape.

 

[Vindicator]

They don't escape, they are emitted.

Nope. They don't escape, nor are they emitted. They depart.

 

[mojo1701]

Don't forget Star Trek. The Enterprise can travel at *several times* the speed of light. Utter nonsense to say that nothing can go faster than the speed of light. IF any of you doubt it, I'll be glad to lend you my old Wrath of Khan tape.

Pfft. In a different medium.

 

[Raven Crowking]

That doesn't work - if the gravitons travel in those other dimensions, gravity does. And that's what'd keeping things from escaping. There is no "back door" out of a black hole into our normal space.

There's a simpler answer - the statement "nothing can escape a black hole" is true, but insufficiently detailed to give us what we need. In full, the statement is "nothing can escape from within the event horizon of a black hole.

In effect, all you need is that the gravitons be emitted from the outside of the surface, rather than from the interior, and all is well.

Of course, that still isn't sufficient, because a rotating black hole has two "event horizons" -- one of which can be escaped, and one of which cannot.


RC

 

[tomBitonti]

Photons inside of a black hole ...

>> As far as the force that bends light being able to slow it down, that's gravity. It might
>> seem obvious to some that this is what happens with a black hole, right? Can't escape
>> 'cause it's slowed down too much, right? No again. Gravity accelerates things, but
>> acceleration isn't always a change in over all speed; change in direction is acceleration,
>> also.

*** A photon trapped in a black hole is now orbitting the singularity ... at the
*** speed of guess what.

My understanding is that there are no stable orbits below the point at which the
escape velocity is 1/2 c. I'd have to go back and read up more to explain why.

Note that anything that passes the event horizon has no hope but to meet the
central singularity. The usual light cone is bent so much that all available paths
point inward.

A photon in a vacuum always travels at c, even inside of a black hole. Note that,
aside from tidal effects, one can't tell that they have passed the event horizon.
Some equations go haywire at the event horizon, but that's because of the choice
of coordinate systems, not because of real (local) physical effects at the horizon.
The only place that is mathematically intractable is the central singularity. My
impression is that folks generally can't describe the physics of the central
singularity.

 

[Umbran]

A photon in a vacuum always travels at c, even inside of a black hole. Note that, aside from tidal effects, one can't tell that they have passed the event horizon.

Similarly, note that the tidal effects at the event horizon may not be large.

Effectively - black holes are what they are because they are a deep gravity well. They only cause notable tidal effects if the sides of the well are steep at the horizon - but the more massive the hole, the less steep the sides. So, while a stellar-mass black hole may rip you to shreds before you reach the horizon, you may be able to waltz across the horizon of a supermassive hole without noticing.

Of course, everyone who enters reaches the singularity eventually, and get turned into spaghetti before they reach it...

 

[Sebastian Francis]

Of course, that still isn't sufficient, because a rotating black hole has two "event horizons" -- one of which can be escaped, and one of which cannot.


RC

Actually, that isn't accurate. I saw the movie EVENT HORIZON, and the spaceship is clearly sucked into the dimensional vortex at the film's end. No escape.