I have an interest in physics, and have taken class, read many books, including all the Hawkins books, and a few others, and read about Einstein... I have no idea what the hell string theory is, nor what M theory is... frankly, while I am not the sharpest pencil in the box, I can usually grasp the regular thoughts, and follow along with the bouncing ball, but this stuff, in my opinion, is physics at it most obscure and math based. This is the theoretical branch that tries to explain the mathematics.... they discover something in a Van de Graf Accelerator, and then try to explain it mathematicaly... I have stopped trying to understand it, b/c no matter how many times I try, it gets worse... plus there is so much background stuff, assumptions, and theory that must be accepted as true, that is just seems ridiculous... just remember that time and space are relative, and you are good to go... thats it for me..