Strongest Evidence for Trapping Light in Schwarzschild Radius

[greswd]

The concept of that when a photon's trajectory intersects with the Schwarzschild Radius/event horizon, said photon will never exit the Schwarzschild Radius/event horizon.

Or any other object besides a photon for that matter.

So far what has been the strongest evidence for this prediction?

 

[Nugatory]

So far what has been the strongest evidence for this prediction?

There is none, as it is far from clear that that “prediction” is correct; if you were to say “flash of light” instead of “photon” you would be on much more solid ground. General relativity is a classical theory that works just fine with classical electromagnetic waves, but photons are a quantum mechanical phenomenon.

So let’s assume that you meant to say “flash of light” instead of “photon”, so that we have an interesting question. In that case the answer is still “none” because we have no direct observations of the behavior of light at an event horizon. However, we do have an enormous amount of observational evidence telling us that general relativity does work everywhere that we can see.
Thus, there are two possibilities:
1) General relativity works everywhere that we can see, and also works at event horizons even though we can’t observe what happens there.
2) General relativity is wrong. The correct theory is something else, something that agrees with general relativity everywhere that we can see, but that because of some as yet unknown physics operating through some as yet unknown mechanism, makes different predictions about what happens at the event horizon.
There’s no way of proving that #1 is right and #2 is wrong... but I know which way I’m betting.

Your question (“What is the strongest evidence for this prediction?”) is somewhat like asking Isaac Newton what evidence there is for his prediction that if tomorrow I drop an object it will fall to the ground. Either Newtonian gravity is correct and the object will fall when dropped, or some other theory that says dropped objects fall today but something else will happen tomorrow is correct. We can’t do the experiment today because it’s not tomorrow... but I know which way I’m betting, and you aren’t seriously going to take the other side of that bet.

 

[Ibix]

The Event Horizon Telescope image of M87* shows a dark spot at the centre of a brighter ring, which is consistent with a dark object at the center. Since the glow comes from gas heated by gravitational in fall, a conventional object at the core would also be glowing from the heat of matter accreting onto it. Something stops that happening.

That, of course, doesn't prove that light doesn't ever escape the event horizon (or even that an event horizon exists), just that there's something there that looks very like a Kerr black hole, supporting GR. And Nugatory's arguments about interpreting that apply.

 

[greswd]

There is none, as it is far from clear that that “prediction” is correct; if you were to say “flash of light” instead of “photon” you would be on much more solid ground. General relativity is a classical theory that works just fine with classical electromagnetic waves, but photons are a quantum mechanical phenomenon.

So let’s assume that you meant to say “flash of light” instead of “photon”, so that we have an interesting question.

so do you think the use of the term "photon sphere" should be discouraged?

In that case the answer is still “none” because we have no direct observations of the behavior of light at an event horizon. However, we do have an enormous amount of observational evidence telling us that general relativity does work everywhere that we can see.
Thus, there are two possibilities:
1) General relativity works everywhere that we can see, and also works at event horizons even though we can’t observe what happens there.
2) General relativity is wrong. The correct theory is something else, something that agrees with general relativity everywhere that we can see, but that because of some as yet unknown physics operating through some as yet unknown mechanism, makes different predictions about what happens at the event horizon.
There’s no way of proving that #1 is right and #2 is wrong... but I know which way I’m betting.

Your question (“What is the strongest evidence for this prediction?”) is somewhat like asking Isaac Newton what evidence there is for his prediction that if tomorrow I drop an object it will fall to the ground. Either Newtonian gravity is correct and the object will fall when dropped, or some other theory that says dropped objects fall today but something else will happen tomorrow is correct. We can’t do the experiment today because it’s not tomorrow... but I know which way I’m betting, and you aren’t seriously going to take the other side of that bet.

I think of it slightly differently than your today-tomorrow analogy.

I feel that its more like Newtonian gravity, the inverse-square law compared to General Relativity, and Galilean Relativity compared to Special Relativity.

Both classical models work well for many of our more easily observable, intuitive scenarios.

And, getting personal here, I do find the newer models quite radical. I'm the kind of person who would still be wowed by observing a spacecraft hit the speed of light barrier due to its relativistic mass, or an event horizon being able to exert an infinitely strong pull at a finite proximity. I guess you could say that i do seem like a neo-reactionary-leaning skeptic. though I'm not making any ill-informed assertions like a crank

 

[pervect]

A strong argument (there may be stronger arguments that I don't know about) for the existence of event horizons is given in https://iopscience.iop.org/article/10.1088/0004-637X/701/2/1357 "The Event horizon of Saggitarius A".

 

[Nugatory]

so do you think the use of the term "photon sphere" should be discouraged?

Not particularly. Natural language is not a precision instrument, so any words we use are to going to be misleading one way or another. Precise and unambiguous descriptions come from the math, not the words we wrap around it.

 

[Dale]

A strong argument (there may be stronger arguments that I don't know about) for the existence of event horizons is given in https://iopscience.iop.org/article/10.1088/0004-637X/701/2/1357 "The Event horizon of Saggitarius A".

This is the paper I was thinking of but didn’t post. Thanks for digging it up.