The Four Conservation Laws of Momentum and Energy

Energy is not strictly conserved in the universe. There's a whole podcast episode we did about that if you want to dig into it but let's just assume we're like living in flat space and we wouldn't notice the expansion of the universe. In particle physics at least we group energy and momentum together into something we call four momentum which combines momentum and energy into one conservation law. So then mass is related to both things like mass makes your momentum go higher and it makes your energy go higher.