Quantum Gravity and the Problem of Time

Most of us think of time as something that divides neatly into seconds, minutes and hours, in a way that’s as regular and predictable at the farthest reaches of the cosmos as it is in our kitchens. But scientists and philosophers have discovered that time has some weird tricks up its sleeve. This week we’re talking about twins who grow older at different rates, broken vases that jump off the floor to reassemble themselves on the bench, and why quantum physicists are learning to do without time altogether.