re: Explaining Einstein
As far as I can tell this is just the general version of his famous formula...
E=mc^2 is the special case for the rest mass energy of a mass, 'm'...
The formula in your post is essentially E=gamma*m*c^2 - this is the energy of a mass m moving with a velocity, v... and gamma is 1 over the square root of (1-v^2/c^2) When v= 0 (as for a mass at rest) gamma becomes 1 and you get E=mc^2- as v appraches c gamma goes to infinity.