SURREY, England — Most of us take for granted that time flows in one direction. We remember the past but can’t recall the future. Photos yellow with age but never spontaneously restore themselves.

Time’s passage is non-negotiable. Its flow marks the progress of our lives, moving clearly in one direction. It is, by nature, asymmetrical. In this way, we perceive it to move like an arrow, ...

What if the flow of time isn’t as one-way as it seems? Researchers from the University of Surrey have uncovered evidence that in the strange world of quantum physics, time could theoretically run both ...

Chanda Prescod-Weinstein comments on the idea that the arrow of time is linked to increasing entropy. What this approach seems to miss is that, while in most systems entropy will almost always ...

Dave Johnson wonders if time can flow backwards in some small pockets of space, given increasing entropy equates with time’s arrow. This shows how intuition fails with huge and tiny numbers. When two ...