Setting our clocks ahead in the spring reminds us that keeping track of time is a human invention. But have we changed the way we think about time over tens of thousands of years? In a program that originally aired last November, Ben's talks with astrophysicist and commentator Adam Frank. Frank's book About Time: Cosmology and Culture at the Twilight of the Big Bang looks at how the human experience of time is braided together with cosmological theories of time.