what is the essence of the universe: energy or matter? Who can tell me the relationship of matter (mass) and energy? it seems that they are not independent. as I think about this question, others comes up as to whether matter can be separated endless, and what the elementary particles are. so far, we know that quark is the smallest particle. but, can we assert quark will be able to stand with stronger high-energy bombardment, which is inaccessible today? i have a feeling that eventually elementary particle might be smallest energy unit? according to this, it seems that matter is energy in nature. is this true? Thanks.