How does light get attracted to a black hole?

[R A J A]

If the mass of the photon particles are zero, then how will the gravitational energy of black hole effect the benting of the light and how will light be atracted towards a black hole when light(photon particles) pass near the event horizon of a black hole?

Edited November 21, 2011 by R A J A

[swansont]

If the mass of the photon particles are zero, then how will the gravitational energy of black hole effect the benting of the light and how will light be atracted towards a black hole when light(photon particles) pass near the black hole?

 

Gravity bends space. The Newtonian model that gravity depends solely on mass is only an approximation. General relativity is a much better approximation.

[R A J A]

Gravity bends space. The Newtonian model that gravity depends solely on mass is only an approximation. General relativity is a much better approximation.

 

so does space have mass?

[swansont]

No, space does not have mass. There are massive objects, and near them the geometry used to describe local space and time is not the same as far away.

[mathematic]

If the mass of the photon particles are zero, then how will the gravitational energy of black hole effect the benting of the light and how will light be atracted towards a black hole when light(photon particles) pass near the event horizon of a black hole?

In general light is affected by gravity (black holes or otherwise). The 1919 Eddington experiment involved measuring light rays attracted by the sun's gravity - a test of General Relativity.

[granpa]

due to gravitation time dilation light will move slower in a gravity well just as it move slower through glass.

 

but if you were in the gravity well with the light you would be slowed too so you wouldnt notice the slowing of the light.

you would both be slowed equally.

[DrRocket]

due to gravitation time dilation light will move slower in a gravity well just as it move slower through glass.

 

but if you were in the gravity well with the light you would be slowed too so you wouldnt notice the slowing of the light.

you would both be slowed equally.

 

 

Light moves at c. In a gravity well, between atoms in glass, or behind the barn, light always moves at c.

 

Light is confined to the interior of the event horizon of a black hole by the curvature of spacetime. Period.

[Latex]

Think of a black hole as water going down a plug hole. You can see that the rim of the hole is the event horizon, and the water as spacetime. If you were to place a pea near to this area in space, you would observe the pea orbiting in a spiral orbit, eventally past the point of no return. I first hear this analogy in a lecture, and has proven useful therof.

 

I cab see why this was brought up, because gravity has still yet to be fully understood.

[Dekan]

Think of a black hole as water going down a plug hole.

 

When water goes down a plug hole, the water doesn't cease to exist. The water comes out of the drain-pipe at the other end.

 

And it's still water. Undiminished in volume, and still chemically hydrogen oxide. That makes sense.

 

But according to you, when water goes down a black hole, it ceases to exist. Could you explain exactly how that happens, as it sounds a bit daft.

[mathematic]

Something going into a black doesn't cease to exist. It just can't get out. What happens inside is unknown.

[swansont]

One has to be aware of limits of analogies. An example meant to explain one aspect of behavior is not invalid simply because the analogy fails elsewhere, where it was not meant to hold.

[R A J A]

Think of a black hole as water going down a plug hole. You can see that the rim of the hole is the event horizon, and the water as spacetime. If you were to place a pea near to this area in space, you would observe the pea orbiting in a spiral orbit, eventally past the point of no return. I first hear this analogy in a lecture, and has proven useful therof.

 

I cab see why this was brought up, because gravity has still yet to be fully understood.

 

So, it means that blackholes are swallowing space-time!

[DrRocket]

So, it means that blackholes are swallowing space-time!

 

No.

 

Black holes are merely a feature of spacetime.

 

Spacetime is in fact static. It embodies all of space and all of time, but spacetime does not "change". What we observe are slices of spacetime, not the whole manifold. So as time progresses we see changes in the slices, but spacetime itself is fixed.

[IM Egdall]

Gravity bends space. The Newtonian model that gravity depends solely on mass is only an approximation. General relativity is a much better approximation.

 

 

Both Newton's theory of gravity and general relativity predict the path of a light beam curves in a gravitational field. For example, starlight grazing the Sun. Newton's model predicts a bending angle of 0.75 arc seconds. Eistein's predicts twice that amount. Observations agree very closely to Einstein's prediction.

[MigL]

Question for you DrR.

You've stated several times now in several different posts that space/time is static and that all space/time events are fixed points on the manifold ( even future events ). Now this is all very well for GR which is a 'classical' theory, since it implies a 'clockwork' determinism, i.e. if you had a big enough computer and could solve all the field equations, you would then know where and when any event would take place.

But just as classical physics was at odds with the emerging field of QM at the turn of the last century, and resulted in the paradigm shift from a deterministic to probabilistic view of reality ( at least at the atomic level ), so will any future quantum gravity theory.

Are you of the opinion that any quantum gravity theory will find these so-called fixed event points on the manifold to be somewhat fluid, or 'smeared-out' and also probabilistic in accordance with the HUP? And if you do why do you keep reiterating the deterministic point of view? Or do you think its too early in the game to call?

Edited December 26, 2011 by MigL