# Black Hole questions

1. Mar 14, 2009

### RustyBullet

Hey guys. I have a few questions about black holes.

First. Is it possible for there to exist a big enough object in space that wouldnt be destroyed by a black hole ? Black Holes have gravity so strong that they destroy any object that comes near it. But, if there was a big enough object, would it be possible for the Black Hole to not be able to destroy it, thus the object actually go through the black hole ? Or maybe even have it's own gravity exceed that of the Black Hole, and have the Black Hole sucked in ?

Second. Black Holes have a gravity so strong that even light is sucked in. But I'm thinking... light doesnt have weight, and even if it could be ripped apart (by the Black Hole's gravity), it wouldnt cease to exist.. the light would still be visible, only in many specks of light.
So what I'm asking is, would'nt light go through the Black Hole, and be still be visible when it reaches the other side ?

Thanks =]

2. Mar 14, 2009

### v2kkim

Even the light responds to gravity. For example a box with a perfect mirror has more gravitational force when it has a lot of photons inside.
Photons in black hole will be attracted to the center of BH and will join the pure mass or pure energy party. In there they loose their past and become a pure tiny thing of volume almost zero or zero. But the overall charge and mass will be preserved.

3. Mar 16, 2009

### Division

First question:

For an object to be able to withstand the strong gravitational force of the black hole, it will have to be incredibly dense, more so than anything we have seen thus far. The closer this object gets to the singularity of the black hole, the stronger will the gravitational force be, but what happens when an object enters the singularity is unknown, but many believe that anything that will enter the singularity will be instantly destroyed. Remember that these are just theories since we do not have the scientific skill, nor the resources to get any type of proof.

Second question:

Many people, when they hear the phrase that light won't escape, think that light does not have mass, but light is made out (as you probably know) by photons, which is matter. Light is photons, that is moving at extremely high speeds. So in all sense, the Black Hole doesn't bend light itself, it bends matter which light is made of.

Last edited: Mar 16, 2009
4. Mar 16, 2009

Staff Emeritus
I'm afraid that's not so.

5. Mar 16, 2009

### Division

Corrected it.

6. Mar 16, 2009

Staff Emeritus
I don't think this is any clearer.

Huh?

I am sorry about the way this sounds, but I can't seem to phrase this in a way that doesn't sound so harsh, and I apologize. But do you know what you are talking about here?

7. Mar 16, 2009

### neutrino8

umm, photons do not have any mass. The reason why light is affected by black holes/gravity in because of warping and curving of space - gravity is not thought to be a vector like force. Photons follow the "surface" of space-time. If curving is extremely strong as is the case with black holes, light won't be able to escape it

8. Mar 16, 2009

### varun19

the escape velocity of the black hole is greater than that of speed of light 3X10^8 ms^-1, so when light gets caught in the blackhole there is no chance for it to get out
earth has an escape velocity of 11.2km/s just to let you know !

9. Jan 9, 2010

### new bee

Could some black holes be a vaccumm held open by matter and energy, surounding it?

Last edited: Jan 9, 2010
10. Jan 9, 2010

### Staff: Mentor

No, that bears no resemblance to what black holes are.

11. Jan 9, 2010

### new bee

Could some black holes be vaccumms held open by surounding matter and energy.

12. Jan 9, 2010

### new bee

sorry I guess i'm confusing black holes, with a vortex. That holds open a vaccumm, light can not enter.

Last edited: Jan 9, 2010
13. Jan 10, 2010

### utku

A compact body curves the spacetime in its vicinity.In General relativity,there arent any forces.The gravitation is directly feature of curved spacetime.So mass curved spacetime and particles have to move in geodesics.Geodesics are shortest paths in spacetime.
If a body collapse under its gravitaion and when it reaches Schwarzschild radius it become a blackhole.Blackholes dont pull the particles or photon.They curved the spacetime and so trajectories of any particles must follow the geodesics.And these geodesics are created by blackhole.The paths of particles end up in real singularity.But when particle or photon cross the event horizon(Schwazschild radius) they cant come back.They dont escape.

Last edited: Jan 10, 2010