The reason for my continued questioning, przyk, is that I've asked (what I feel are) some pretty basic, logical questions about black holes to many people that I would assume would be able to supply straight-forward, well established, community-accepted answers. Here's a version of my logical conundrum: ========================================= #1 Do you agree that all frames outside of the BH calculate that no mass crosses the EH using Schwarzschild coordinates (or, more specifically, mass crosses the EH at t=infinity)? #2 Do you agree that the EH does not expand until mass has crossed the EH (i.e. backreaction)? If you concur with #1 and #2, then run the clock backwards in your mind and describe to me how this theoretical black hole formed in the first place... ========================================= To this point I've received many responses including the following: 1) Backreaction occurs before EH crossing (as CptBork asked above) 2) Unruh radiation 3) Vaidya metric 4) Kruskal coordinates 5) The finite proper time of the in-falling body proves the BH's existence 6) "A very famous man told me so" (this is my favorite) 7) Speculative "mystery mechanisms" 8) "Here, check out my class notes" (implying, to me, that they feel the answer was explained to them in class but they didn't understand it either) ...and in each case, upon further probing, the person making the defense admits that they don't completely understand it themselves (or they quietly go away). In fact, you're the first responder that has doggedly tried to explain your defense (with patience and maturity I might add! Well done, sir). Anyway, it appears to me that you're trying to make the case that, Schwarzschild calculations be damned, Kruskal "proves" that in-falling bodies do so in finite outside observer's time. How a coordinate change, rather than an additional physical mechanism, explains this dichotomy I still don't understand. This strikes me as a violation of something for which I have no name but I suspect is very fundamental to the mathematicians here. A coordinate change should not affect the inertial calculation of the time required for a free-falling body to cross the EH! Your response to this is that the phrase "time required" to do something is simply a label and apparently doesn't actually measure anything..? Again, this bewilders me. Let me ask you this: in Kruskal coordinates, is V given the label of "time component" arbitrarily? Could Kruskal just as easily given U the label "time component", or was V chosen for a reason that ties V's behavior specifically and solely to the temporal dimension? I have more questions but I think I'll wait for you to respond to this. BTW, regardless of whether I think this is a valid explanation of BHs or just unintentional obfuscation, I'm learning a lot and rather enjoy the exchange.