This hour, Radiolab goes to the front lines with men and women who are battling against time -- or at least the common-sense view of time.

Einstein's Theory of Relativity may have implications on the concept of choice. Namely, that there is none. Do we choose what movie to see tonight? No. (It's already been chosen, some say.) Do we choose to wiggle our finger? No. (Already wiggled.) We'll visit a particle accelerator where scientists recreate the moment just after the beginning of time, and a Dublin artist whose life is a 19th-century time experiment. We end in the Mojave desert, where geologic time flows like a frozen hourglass.