Before 1920, our world picture was something like this: The “stage” on which the universe goes is the three-dimensional space of geometry, as described by Euclid, and things change in a medium called time.

Why, to us, is the past so different from the future? Nineteenth- and twentieth-century physics engaged with these questions and ran into something unexpected and disconcerting—much more so than the relatively marginal fact that time passes at different speeds in different places. The difference between past and future, between cause and effect, be

... See more

- “The first thing to note is that pretty much everything is a clock. Garbage announces the days with its worsening smell. Wrinkles mark the years. “You could tell time by measuring how cold your coffee has gotten on your coffee table,” said Huber, who is now at the Technical University of Vienna and the Institute for Quantum Optics and Quantum Inf... See more