Entropy in the Universe is increasing. Why? What is going to happen when it runs out of its energy? This is a fascinating question (so beautifully covered by Asimov in The Last Question) because it pertains to quite possibly the most universal of all concepts of the Universe. Ever increasing entropy is the reason we die; it’s very likely the reason no alien race has contacted us yet; in my opinion it’s intrinsically linked to the reason why time flows in a single direction.

But does it have to be that way? First, what would the Universe look like if entropy did not increase mercilessly? Would it even be allowed to exist? If the flow of time — and thus causality — is linked to entropy, it seems that Universes without that ticking clock would be unstable, ethereal, essentially nonexistent (existence, I think, can only be defined in a knowledge base that also includes time).

Could entropy be reset? Or, in other words, what happens once the Universe reaches its maximum level of entropy (and we now know that such a maximum exists as nothing in nature is infinite — probably another implication of the existence of entropy and thus the Universe’s stability)? The Universe — its existence, history (which requires information, and thus entropy) becomes undefined. Cause and effect cease to exist. The last sigh of a dying Universe nullifies everything the Universe has ever been. The undefinable entity that is the Universe post mortem is no different than the undefinable entity that is the Universe before its birth. And in that chaos where everything is infinite, the proto-Universe has a lot of time to invent the concept of entropy all over again.

This reminds me of how I thought of an afterlife some time ago — we are immortals who one day choose to live a life of a mortal with no recollection of their former selves. If that’s the case, we might just as well enjoy our life before we return to our regular immortality.

So go ahead, destroy the Universe.