I know there are many theories as to why time travel is impossible (as well as many about why it is possible) but I just had a huge flash of insight as to why time travel is probably impossible - one I've never heard before.

If there is a fixed amount of matter in the universe (and therefore, energy as well), we are "stuck" in the present at all times - otherwise, we would increase the mass of the universe at the point in time we travel to, while reducing it where we depart from. In order to time travel, you would have to change the entire universe at two separate points in time. Not enough energy in the universe to do this. And you wouldn't get around it by saying it still balances out if you consider the entirety of history ("minus" you here + "plus you" there = zero) because you have to account for the reduction in mass in the intervening "time", and the addition of mass at the arrival point (unless the "you" in the past or future disappears as soon as "you" arrive).

Therefore, time travel is impossible. Probably.

If I could still get ahold of any microdot mescaline, than I'd be more than willing to try and test out your hypothesis. Alas, it's not to be.

I wasn't even drunk when this came to me, that's the scary part.

Kim explains the Casimir Effect and the theory of Divergent Timelines and Parallel Worlds.  I think she might appreciate your theory.

!i!