SoylentNews

AnonTechie writes with news of a story in Ars Technica:

Apparently, time goes in one direction. But why?

The answer to why time has a direction takes many forms, usually described as "arrows of time." We've had time defined by how information increases or how entropy increases. But all of the arrows we've considered are a bit unsatisfactory. For instance, an arrow of time derived from entropy starts with the assumption that the Universe had to begin in a highly ordered state. If that assumption fails, so too does our explanation for time.

The thermodynamic arrow of time also conveniently ignores gravity. When gravity dominates, it spontaneously orders stuff—this is why we have galaxies. So although the thermodynamic arrow of time suffices for parts (any part) of the Universe, it doesn't work for the whole Universe or the whole of time.

A new paper ( abstract; pdf ) in Physical Review Letters presents a new arrow of time, which the authors hope might lead to a sort of general description from which all the other arrows can derive their power.

I hope somebody more knowledgeable, at SN, would be able to explain this.