Yeah I' ve seen that argument before. In the case of using entanglement for communications. I have no wish to misdirect this thread. Howevee to me thats like saying a particle either has all or no information till examined
This should really be discussed in the quantum physics forum, not here; getting into it further here would indeed misdirect the thread. If you want to post this as a separate thread in the quantum physics forum, feel free to put a link here so whoever is interested can follow up.I have no wish to misdirect this thread. Howevee to me thats like saying a particle either has all or no information till examined
...The outside universe doesn't have to "see" any changes in the singularity; it "sees" the mass falling into the hole...,
PS; In his argument over the years with Stephen Hawking, Susskind was correct in his interpretation of BH !Black Hole Complementarity
Leonard Susskind, THE BLACK HOLE WAR (his arguments with Stephen Hawking)
In this view, all the information ever accumulated by a BH is encoded on a stretched horizon...a Planck length or so outside the event horizon and about a Planck length thick. This is a reflection of the Holographic principle: all the information on the other side of an event horizon is encoded on the surface area of that event horizon....
Of every 10,000,000,000 bits of information in the universe, all but one
are associated with the horizons of black holes. [So if you can lose information via black holes, it a really,really,really big deal.]
(p238) Today a standard concept in black hole physics is a stretched horizon which is a layer of hot microscopic degrees of freedom about one Planck length thick and a Planck length above the event horizon. Every so often a bit gets carried out in an evaporation process. This is Hawking radiation. A free falling observer sees empty space.
(p258) From an outside observer’s point of view, an in falling particle gets blasted apart….ionized….at the stretched horizon…before the particle crosses the event horizon. At maybe 100,000 degrees it has a short wavelength and any detection attempt will ionize it or not detect it!
(p270)…. eventually the [incoming] particle image is blurred as it is smeared over the stretched horizon and….and the image may (later) be recovered in long wavelength Hawking radiation.
It is a causal boundary and to me that's quite physical....but what we call it varies a lot.I wonder if it is correct to call the EH a "surface" since it is in no way physical ....
The term "surface" is pretty general; it can apply to just about any submanifold of a spacetime. The EH is the set of all points in the spacetime with r = 2m, but with no other coordinate constraints. A more precise term for it would be a "null 3-surface", meaning a submanifold with three linearly independent tangent vectors, one of which is null. (The other two are spacelike.)Naty, I wonder if it is correct to call the EH a "surface" since it is in no way physical and really is just a spherical coordinate r.
It's an unambiguously specified set of points in spacetime. No matter what coordinates you're using, if you present me with the coordinates of a point, I'll be able to answer the question "is that point on the EH?" and the answer will be same no matter which coordinate system you choose. That strikes me as a pretty good operational definition of something that is "physical".Naty, I wonder if it is correct to call the EH a "surface" since it is in no way physical and really is just a spherical coordinate r.
I was just reading the other posts and remembered ALL the horizons we discuss in the forums have 'physical' attributes...like the Rindler horizon associated with Bells Spaceship paradox and Unruh effect....and Hawking radiation of black holes.I wonder if it is correct to call the EH a "surface" since it is in no way physical and really is just a spherical coordinate r.
'perturbations' ARE particles! Without such horizons we would be in an empty universe.It's a nice exercise though to work through the evolution of a scalar field fluctuation during inflation, from its birth in the vacuum out to super horizon scales if you haven't done it. What you find once you've done this is that you end up with a spectrum of perturbations across a range of length scales.