In "The energy that holds things together" Physicist Matt Strassler in his "Of Particular Significance" blog discusses how things are held together by the energy of the fields that make up the universe. It gives a slightly different view of things from what I am used to seeing. Good stuff.

Bill S. He mentions potential energy, but doesn't want to call it that because the usual explanation is much different from the modern description.

Bill Gill

C is not the speed of light in a vacuum.
C is the universal speed limit.