Are multiverses real? If so, what do they look like? How do you get there without disturbing time? – Emily, age 9, Pune, ...

For over a century, scientists have thought of time as a fundamental property of the universe. But the more researchers seek ...

In the strange world of quantum mechanics, objects can exist in several states at once. This concept, called superposition, is one of the most puzzling features of quantum theory. A particle, for ...

Joseph Polchinski, one of the most creative physicists of his generation, whose work helped lay the mathematical foundation for the controversial proposition that our universe is only one in an almost ...