Using a simple simulation of gravitationally interacting particles, the researchers show that an orderly universe should always arise naturally at one point in time. From there, the universe branches in opposing temporal directions. Within each branch, time flows toward increasing disorder, essentially creating two futures that share one past. “It’s the only clear, simple idea that’s been put forward to explain the basis of the arrow of time,” says physicist Julian Barbour, a coauthor of the study published last October in Physical Review Letters.
An interesting article I stumbled upon. Is there a "gravitational arrow of time" rather than a thermodynamic one?