Time after time, physicists have tried to explain time. Many claim to have succeeded. But they haven’t. Otherwise everybody would quit trying to explain it all over again.
One of the most recent such efforts comes from the mathematician/cosmologist George F.R. Ellis. He thinks solving the time mystery involves figuring out the difference between the past and the future.
That’s not as obvious as it sounds. Physical laws governing motion make no distinction between future and past. Equations describing the scattering of billiard balls on a pool table work equally well if all the balls retrace their paths to form a neat triangle. Films of molecules flailing around look the same in forward or reverse.