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Jan24-10, 06:27 PM
Sci Advisor
P: 8,470
Quote Quote by Phrak View Post
How long does it take for a black hole to form? How long does it take for its mass to increase? What is the age of the universe? What is the theoretical justification for claiming accreation disks, jets, and other evidence of black holes are not also evidence of pre-collapsed dense masses?
Could you answer my question about whether you are willing to accept the likelihood that GR (plus quantum field theory on curved spacetime, perhaps) is correct when dealing with energy densities far below the Planck scale? In the context of GR your questions about black holes should all have well-defined answers, but perhaps you are questioning the validity of GR itself? Or maybe you accept GR, but wish to use a coordinate system (like Schwarzschild coordinates) where it takes an infinite coordinate time for a collapsing star to actually reach the Schwarzschild limit? (if the latter, note that all coordinate systems are equally valid in GR and there are plenty of coordinate systems where you can cross the event horizon in finite time, and any particle in the star will cross the horizon in finite proper time regardless of what coordinate system you choose)