Would a black hole 'shred' a photon.

If a black hole can exist...

Would not that justify the existance of an object that has absolutly no gravity? (all things having a balance)

We need to start by saying that, within a black hole, everything that we know about the physical universe breaks down.

Black holes are phenomena where a massive body has distorted space-time and created a region that is inescapable by anything, even light. Around the black hole is a boundary surface called the event horizon, past which nothing can escape the black hole's gravity well. At the centre is a singularity, a supermassive body that is infinitely dense: it occupies an infinitely small amount of space. A black hole is formed when a star of sufficient mass dies and collapses upon its self under its own gravity. The escape velocity necessary to leave the gravity of the black hole beyond the event horizon is greater than the speed of light.

F - force
G - universal constant of gravitational attraction
m - mass of body (m1 and m2)
r - radial distance between the bodies being considered

Universal Law of Gravity

F = G(m1*m2)/r^2

Also, F = m*a (a - acceleration)

Thus, if m1 is the mass of the body and m2 is the mass of the singularity,

F = m*a = G(m1*m2)/r^2 --> a = G(m2)/r^2

We see that the gravitational acceleration caused by a black hole (or any body) is the product of G and the mass divided by the squared radius of distance between the two bodies.

A photon is a unit of light energy, so to speak. As such, it cannot be destroyed. When a photon is captured by the gravity field of a black hole, it falls to the singularity and we cannot say exactly what happens to it. The singularity of a black hole cannot be directly observed.

A black hole is not a body with infinite gravity, and it is a consequence of the theory of relativity. The proposed 'balance' to a black hole is a white hole, a body that cannot be entered from the outside, but permits things to escape it.

Moreover, it is not necessary for there to be balance of properties; that is a property of forces.

http://en.wikipedia.org/wiki/Black_hole

Good question.

Photons are tiny packets of energy. They typically are not "shred" by other forces like gravity, they just get absorbed by the electromagnetic field of some "normal" matter (specifically not dark matter)or just add some kinetic energy to whatever they slam into. Whatever exists at the core of a black hole would probably just absorb it too.

Makes me turned on and want to listen to Muse's Supermassive Black Hole song...

http://www.youtube.com/watch?v=cW7BvabYnn8&NR=1&feature=fvwp

A primer on supermassive black holes

I'm confused. By "turned on" are you saying you queued up your music, or that you are aroused?

Since I don't quite understand gravity, or black holes, I have no clue.

As I understand it, photons cannot have gravity because they have no mass.

Those all sound logical, but why does a black hole not start absorbing all the spacetime in its immediate area like a sponge soaking up water and all the spacetime beyond that, etc? Like photons, it should be able to enter but unable to leave, right? And if spacetime can expand indefinitely, then can it also contract indefinitely?

Hi Sky!!

Bushidobillyclub seems to think that black holes have enough gravity to suck in light photons. I don't think that is what is happening there.

Photons indeed are held to have no mass, however they are effected by it.

Under GR space time itself is bent in the presence of mass, this means that any particle that travels through space time is also effected by the mass.

No contradiction what so ever. Black holes do indeed have enough gravity to such in photons hence them being called BLACK holes.

Have you ever read about the idea of shadow photons? (The book: The End of Time" by Julian Barbour.) Have you read it? If you have please explain it to me. LOL

I admit I have not read a lot of the book and I find it difficult to comprehend, its probably way over my head, and I'm not so sure he is even on the right track, but he talks about some very interesting experiments with light.

I suspect the nature of reality may be similar to how a holographic projection works, which is Dependant on light. The true nature of reality could be flat.

How that relates to a black hole, I will have to think about.

Not familiar, perhaps I will order his book.

What people have said about the book:

For the physicist Julian Barbour, time is an illusion. In this "revolutionary" new book he argues that, paradoxically, we might be able to explain the mysterious "arrow of time' - the difference between past and future. -- by abandoning time altogether. But to understand how, we need to change radically our ideas of how the Universe works...
(Jon Turney, Guardian)

He tells a timeless story, making the case for time being an illusion, not merely in the ethereal realm of quantum gravity near the Big Bang where Stephen Hawking and James Hartle have made the same case, but in other areas of physics as well. (John Barrow, Sunday Telegraph)

Yea I read that, not very compelling honestly. No meat. To be expected, its an intro for a pop-sci book.

A review I dug up with a tad more.
http://www.chronon.org/reviews/End_of_Time.html

If a photon has energy then it should follow that it has mass. According to Einstein,

"It followed from the special theory of relativity that mass and energy are both but different manifestations of the same thing -- a somewhat unfamiliar conception for the average mind. Furthermore, the equation E is equal to m c-squared, in which energy is put equal to mass, multiplied by the square of the velocity of light, showed that very small amounts of mass may be converted into a very large amount of energy and vice versa. The mass and energy were in fact equivalent, according to the formula mentioned above. This was demonstrated by Cockcroft and Walton in 1932, experimentally."

Since all mass is nothing more than energy, mass does not necessarily have to occupy any specific volume of space thus allowing the incredible mass of a black hole to occupy an immeasurably small space. This allows a continuing build up of Gravitational Force, which is neither mass nor energy to draw more mass into a smaller space, increasing the mass, and energy in the space, while reducing the size of the space and increasing the Gravitational force in the space.

I don't know about you but I'm getting a headache. lol