“About time: Adventures in the fourth dimension” is an interesting series of New Scientist articles on that famous fourth. It’s essentially a bid for subscriptions, but while you decide, you might learn, for example, that “The essential nature of time remains the universe’s greatest mystery.” Hmmm. We’d thought the essential mystery was the exact relations between the four fundamental forces, but now that writer Sturt Clark mentions it, ….
Or this from Amanda Gefter:
As we know only too well, time, unlike space, has only one direction – it flows from past to future, and never the other way round.
. A thorough search of the laws of physics turns up no such arrow of time. For example, you can use Newton’s laws of motion to work out where a ball was thrown from in the past just as well as where it will land in the future.