RE: Why E does not equal mc^2
A unit of Planck time is the time it takes for light to travel, in a vacuum, a single unit of Planck length. Taken together, they form part of the larger system of natural units known as Planck units.
I might be completely wrong here, but it appears that when Einstein came up with general relativity he presumed a universe where everything moved at the same speed, not one that was in variable motion and certainly not involving quantum forces like black holes.
Still working through this. My physics buddy is starting to get pretty excited and he's the math whiz.