diomedea

The universe as it appears to us holds many misteries. But we can only see 4 spacetime dimensions and many things escape our grasp.
The universe we know is just one in the multiverse, its dimensions more and elusive.
Entropy, as time, flows in just one direction in our universe. Which appears doomed to expand forever and vanish at the end of time.
Accounting for some other dimension, entropy and time may well appear cyclical; a parallel universe condensing to balance expansion in ours.
Sum of mass and energy never change in our universe... unless there is a transfer across some unknown dimension to another universe.
Sum of mass and energy never change in the multiverse. Let's consider our knowledge of physics is still incomplete, don't rule out something just because current theories say it would be impossible.