Can light orbit a black hole?

how much energy a black hole can absorb before it overcomes the gravity field

As a photon doesn't have mass, how could it be affected by gravity?

there a theoretical limit to how much energy a black hole can absorb before it overcomes the gravity field?

Are neutrinos orbiting black holes?

than any orbit that is not exactly equatorial should not be stable for a photon. So no photonsphere but a photonring (if that)?

Wouldn't the photon sphere be regularly disrupted by in falling matter as the light would excite matter?

As an atom nears the event horizon, the pull of gravity on the near side is stronger than the pull of gravity on the far side of the atom. The difference is so great that it will overcome subatomic bonds and rip the atom into subatomic fundamental particles.

As an atom nears the event horizon, the pull of gravity on the near side is stronger than the pull of gravity on the far side of the atom.

this "spaghettification" applies to stellar mass class black holes, but not to the much larger ones in the centers of galaxies. For the latter it happens much closer to the singularity

IIRC for supermassive black holes you could survive falling through the event horizon

if you're a photon moving at your usual speed and you cross, the gravity will accelerate you, right?

There couldn't be a photosphere inside the EH

So, when we're talking about the photosphere we MUST be talking about a smaller black hole

In that case, it will reach the center and then INSTANTLY stop, right?

The conditons (given a fully static black hole) should be satisfiable for small and (large) black holes

Not really. It will just blueshift the photon as it falls in

The instant you cross, it takes velocity above the speed of light to move anything outwards, so how do your subatomic bonds hold together when there's no signal coming from immidiately next to you?

In order to have frequency, don't you need a wave? Can there be a wave inside the EH?

all geodesics [originating from any point within the EH] point to areas of higher gravity

Falling through the EH does not mean that one is moving at the speed of light at that point. You can cross it as slowly as you like given good drives.

BUT there is no force pushing you back to the that point when you move from it (as would be the case if you were really at the center of a gravity well)...weird

The instant you cross, it takes velocity above the speed of light to move anything outwards, so how do your subatomic bonds hold together when there's no signal coming from immidiately next to you?

You're still thinking of this as SR; it's GR. You're in free fall, not using reaction mass to accelerate through space.[Blah, blah, blah myself]

Falling through the EH does not mean that one is moving at the speed of light at that point. You can cross it as slowly as you like given good drives

G, is that what you're saying makes sense in a context where acceleration is the result of particle interactions in space

BUT there is no force pushing you back to the that point when you move from it (as would be the case if you were really at the center of a gravity well)...weird

And no matter which way you try to move, even though it may appear that you are moving in some other direction, as all your accelerometers and such would tell you, you'd actually be moving towards the center, right?

Since we believe all forces, even the fundamental subatomic forces, propagate at C, as soon as you cross the EH, your warp drive engine will disintegrate

you'd actually be moving towards the center, right?

@Jizby: What in the world was all that supposed to mean?

a gedoesic is defined as the least time path between any two points given a constant speed

If a photon can orbit a black hole, is it possible for a photon to slingshot around a black hole? If so, can we see earth as it was thousands of years ago

The force that holds them together would not be able to mediate (nuclear force). Then again: neither would the force that pushes them apart (electrostatic force)

I can't see how anything other than fundamental particles would be permitted beyond the EH.

But here's the weird bit. This process would rob gravitational energy from the BH

however this energy is then transformed into mass as it creates a new quark. Would this new mass then create enough gravitational potential to counter what was lost when the proton was ripped apart?

speculation alert!!! for those who read this, beware

No new gravity magically appears when energy is transformed to mass, it was already present in the energy field before transformation

It is correct, for example photons mediate the (portion of) matter of star during supernova explosions. When the mass travels across space in form of photons, it just means that the gravitational waves are present inside of each photon. The mass m, of a photon is related to its energy E or wavelength λ of the photon through the Einstein relation E = ��Žc/λ = mc^2. The fact that the photons can mediate mass has been proven experimentally already: for example the gamma ray photons http://www.ncbi.n...20438075 the mass (of atoms) of some isotopes by their excitation, which can be subsequently detected with mass spectrometer, when these isotopes are deexcited and radiate their energy into gamma ray photons, then the mass of atoms is returning back.

I would think the photon sphere would be exactly the same radius as the event horizon.

Sorry guys, but you're just wrong about this. It's widely accepted, for a sufficiently massive black hole NOTHING SPECIAL happens to the observer when they cross the EH

Yes, I've seen that many times in print, and you've got to understand that is a layperson's simplification

Once u cross any EH, the absolute acceleration due to gravity is greater than C/second squared. That is the definition of an EH. No forces can be communicated upstream once you cross an EH. No forces = no atoms. You would not survive this

gawad:

It's widely accepted, for a sufficiently massive black hole NOTHING SPECIAL happens to the observer when they cross the EH

Yes, I've seen that many times in print, and you've got to understand that is a layperson's simplification. That only applies to the tidal force, and its ability to physically distort you. It does not consider the whole picture of what's going on.

gawad:

It's widely accepted, for a sufficiently massive black hole NOTHING SPECIAL happens to the observer when they cross the EH

Yes, I've seen that many times in print, and you've got to understand that is a layperson's simplification. That only applies to the tidal force, and its ability to physically distort you. It does not consider the whole picture of what's going on.

It's widely accepted, for a sufficiently massive black hole NOTHING SPECIAL happens to the observer when they cross the EH

Until (s)he doesn't hit the firewall or worm hole. The information paradox clearly says, that the information (about falling object) cannot be preserved bellow event horizon. The only question is, where exactly it will be destroyed.

Hawking's old theory had no firewall attached to a big black hole as opposed to quantum sized black holes that emit radiation emanating from virtual particle pair production. What causes the firewall around a big black hole in his new theory? His old theory had very limited virtual pair production and low amounts of hawking radiation released from bigger black holes.

what would make all matter splatter at a black hole event horizon or whatever is limiting entry into its interior? I don't understand how the firewall is supposed to work. Can you explain it?

Yes, I've seen that many times in print, and you've got to understand that is a layperson's simplification. That only applies to the tidal force, and its ability to physically distort you. It does not consider the whole picture of what's going on.

IMO most realistic scenario is

But I predicted this outcome before seven years already, when I said, that the black holes are dense neutrino stars.

the curvature at the horizon of its central black hole is only about twenty times the spacetime curvature here at the surface of the Earth—which we don't even notice!

They are neglecting to account for what happens due to the observer's own atoms and electrons no longer being able to communicate with eachother. To say that you wouldn't notice this is naive.

Are you proposing that anything can travel up-stream inside the EH? If so, I'd sure like to see a source that says that's possible.

In a relative sense, however, yes
they all just in freefall and can exchange relative to each other

There are galaxies receding away from ours faster then c because of ST expansion, did they get atomized when they went over our horizon? Did we when we went over theirs?

They are neglecting to account for what happens due to the observer's own atoms and electrons... have actually read some theorists who claim that observers who fall past the EH near each other might continue to communicate, but that's just stupid... No, that's not how it works.

There are galaxies receding away from ours faster then c because of ST expansion, did they get atomized when they went over our horizon? Did we when we went over theirs?

At the EH of a black hole, that communication block happens at the planck scale.

Electrons and other subatomic particles will be fine, but their ability to stick together depends on them being able to interact with each other.

You do understand that they cannot communicate with each other, right?

The gravitational field at the EH of a black hole is a whole different kind of EH than other types of EH.

Look up the wiki page on event horizons.

There's a short description of various types [of horizons] there. They are not all the same.

Beyond the EH of any BH, the gravity field is of such high magnitude that every Planck length down is cut off from the outside above it. It is like an infinite, nested series of the cosmological EH's you're talking about.

If you can still communicate, you're not in the EH.

i'm not sure about you. did you have an ivy league education?

Sorry, G, but that's gold, man ;^)

cheers. whats IMHO mean?

cheers. whats IMHO mean?

Eh, I think that's incorrect

It doesn't matter whether you perceive youself as having crossed the EH or not. An outside observer would see you cross and disapear, and as such, anything that crossed the EH before you would appear to be gone, from your point of view

Sorry, G, but that's gold, man ;^)

Eh, I think that's incorrect. I guess we disagree.

Each observer never sees themselves cross the EH, but anything that crosses the EH before you is essentially gone from your universe, and anything that crosses the EH after you has already seen you disapear forever.

The quote you have from the wiki is a commonly repeated mistake. As I said earlier, I've seen that in a lot of places.

It doesn't matter whether you perceive youself as having crossed the EH or not. An outside observer would see you cross and disapear, and as such, anything that crossed the EH before you would appear to be gone, from your point of view.

You are all in denial. But, as they say, ignorance is bliss. Untruths look better because they are so pure.

Remember Ocham's razor. The truth is simple.

i'm not sure about you. did you have an ivy league education

No G, an outside observer NEVER sees you cross the EH. That's cannon

"In my humble opinion"

No G, an outside observer NEVER sees you cross the EH. That's cannon

That's easily argued against. If that's the case, then you'd still see everything that's ever been pulled into a black hole, and we would be able to detect them. They wouldn't be black, rather they would be glowing brightly in the deep red.

So I'm not buying the idea that you would never perceive something crossing the EH.

Auburn University, Auburn Alabama, Aerospace Engineering (though that's not my current field), as if that matters here

That's easily argued against

pretty much exactly what Relativity proposes: the outside observer sees everything that goes in just "fade to black" (going through the deep infrared) at the EH. Like I said, cannon

Yeah, that's the most widely accepted interpretation, but not the only one

There is still huge difference in opinions of physicists.