Einstein's famous equation equating energy with mass, revealing that mass is a form of energy, is an elegant and tremendously useful equation. However, is it telling us anything about the nature of our universe? For example, we might ask what is the mechanism by which energy manifest very specifically in the invariant masses of elementary particles: why that mass and not another? Or, even more basically, why do particles have this property of mass at all? When we start to break down the equation

Einstein's famous equation equating energy with mass, revealing that mass is a form of energy, is an elegant and tremendously useful equation. However, when drilled down to the fine-grain level all the terms of the equation are largely undefined. The speed of light is listed as a constant without a very clear reason why it is that velocity and how that is involved in relating mass and energy. Energy is the capacity to do work, but what is it physically and what is the source of energy in the uni