For those of you who think that mass can be defined as nothing more than "concentrated energy", consider the following:
Take an example of "pure" energy such as photons. Now clump them all very tightly to form as mass per the scenerio of the OP. Now explain to me the following:
1. photons have no charge, yet, electron, quarks, etc... all do. Where do these charges come from?
2. Photons have spin of 1. elementary fermions have spins of 1/2. How do you get the basic projection of the "units" of 1 to get spin of 1/2?
3. Photons do not interact via the weak interaction (they don't, at this point, participate in strong interactions either, but in some postulated theory, they might in higher order interactions). Yet, we know many particles that do. Where did that come from?
Zz.