In quantum gravity, people are arguing about firewalls. Are black hole horizons hot or not?

Both sides argue with what happens behind the horizon. Yes, "behind" it. Of course, behind a horizon there is whatever you want. Behind a horizon there is only religion. Behind a horizon or outside the universe is the same. Whatever one says about it, it is nonsense.

I am missing a simple and clear discussion on whether a Rindler horizon is hot. That would be refreshing and clarifying.

But reading papers that use unproven conjectures in non-existing regions to make either one point or another shows only one thing: quantum gravity is mainly a belief system.

They've obviously got a bit stuck trying to make gravity into a quantum field theory. Why don't they try going the other way?

ReplyDeleteWhy don't they try making the electromagnetic interaction into a curved electromagnetic space, the strong interaction into a curved strong space, and the weak interaction into a curved weak space?

So what you would have is a curved spacetime containing curved electromagnetic, strong, and weak spaces (so those spaces would be doubly curved, I suppose -- once by their own curvature and again by the curvature of spacetime).

Dear Anonymous

DeleteFirst,I also believe that the right way is the other way around,namely to make QFT(or SM) compliant with GR

Second,the reason for not doing so is that the vast majority of physicists are QM physicists and naturally believe that QM(QFT,SM) is the most fundamental physical theory,more so than SR and GR which I believe is wrong thinking

So this is why ST is a quantum theory and it is stuck

People do not realize that gravity(GR) is not just another forth force in physics,but the space-time fabric to which all other forces should comply

Dirac understood that when he changed QM such as to comply with SR ,antimatter being the result

Still,before doing all this one should first regularize both SM and GR appropriately

Abraham

Dear Abraham,

DeleteIf I recall, it was the renormalization that bothered you. That business with infinities smells fishy to me too. Is one way to get rid of infinities to change the frame of reference (or maybe the terms of reference)?

I'm not sure exactly what I mean but, for example, the frame of reference of a photon is no good for measuring its speed: its time is nought and so its speed is infinite.

Were you drunk when you wrote this?

ReplyDeleteDid I say something absurd?

DeleteWhy is it absurd to consider making the quantum interactions into curved spaces but not absurd to consider making curved spacetime into a quantum interaction?

I'm not saying that it isn't absurd. I don't even know how much I don't know.

Clara hi

Delete1.I think you are right that ST,QG,TOE,ANTHROPISM etc are approaching a theological character so maybe gradually Physics Nobel prizes will become more spiritually inclined...

2.The Rindler hot horizon problem is easy because there is no absolute zero(kelvin) temperature in physics ---of course the Rindler horizon temperature is still extraordinarily cold compared to "earthly" temperatures.During the last few years there have been some interesting papers in PRL dealing with this issue ,the purpose being to mitigate the BH singularity problem

Abraham

None of interactions work in curved spacetime, that's the answer. People tried and failed.

DeleteTo your first question: yes.

ReplyDeleteOk back to your post.

DeleteSo they are talking about a hypothetical observer who falls into a black hole. But the gravity is so strong that the observer would be shredded by the tidal forces long before they got to the horizon. If the black hole was bigger, the tidal forces would be less extreme. How far does the observer have to fall towards a really big black hole before the tidal forces become as big as the maximum force in nature, c^4/4G, I wonder?

Wouldn't it have to be at least as far as to the horizon of the black hole (otherwise after that point, the tidal forces would have to exceed the maximum force -- which isn't allowed)? But then if it was after the horizon that the tidal forces would equal the maximum force, it wouldn't be the tidal forces that made it impossible. Are the tidal forces at a horizon ALWAYS equal to the maximum force?

I did a search for the word 'tidal' in Schiller's Motion Mountain, vol.6, but nothing came up.

Maybe an observer would only get shredded at the horizon if they were massless. Maybe the more massive is an observer, the further from the horizon it is when they get shredded.

DeleteBut then what if instead of an observer, it was another black hole? The tidal forces would have to shred both the black holes in order to reform their horizons into one big black hole instead of two smaller ones... or something. At no point could there be any apparent crossing of their horizons.

I wonder what actually happens when black holes collide. Maybe it has already been seen but not recognized as such.