User blog comment:PitaKang/Funday Monday 3: What would an interstellar civilization look like?/@comment-1789156-20130501205211/@comment-1789156-20130510172722

Actually the majority of your mass is from energy itself. Up and down quarks in a proton, for example are only about 1% of its mass. Through m=E/c^2 we see that we can get mass from lots of energy. Through energy fluxuations in the gluon field and the quarks interacting from these gluons, we get mass. Although it can't be measured on this small of an instance, this can be applied to the old story of Einstein saying that a hot cup of tea has more mass than the same cup of tea when cold.