[Vodstok]

e=mc2 is a calculation to show that as speed increases, so does relative mass. This is how they came to the conclusion that light speed is impossible for true matter to reach, since as an object hit light speed, it's mass would become infinte, and therefore stop moving. It has very little to do with the expansion of the universe, except that the universe is apparently breaking this rule by speeding up as it ages, rather than slowing down.

Also, as far as the mouse and the elephant go...

Biologists believe that pretty much every animal has the same number of hearbeats in it's lifetime. But smaller animals have MUCH fater heartbeats, there fore live shorter lives. Elephants have extremely slow heartbeats (comparatively speaking), so they live much longer.

Humans appear to fit this equation as well, but thanks to medical technology, we are able to take a huge piss on natures plans.