Like a visually ambiguous Necker cube, the famous Sleeping Beauty problem can be perceived in two seemingly valid ways.

Two leading candidates for a “theory of everything,” long thought to be incompatible, may be two sides of the same coin.

The irreversibility of time may be a clue as to what makes up the universe’s dark matter.

Coils and twirls in DNA’s double-helix change how the molecule behaves, opening a new role for topology in the study of life.

The solution to this month’s puzzle explains how to design a Sudoku square to figure out the likes and dislikes of four or eight finicky friends.

Three years ago, a solitary mathematician released an impenetrable proof of the famous *abc* conjecture. At a recent conference dedicated to the work, optimism mixed with bafflement.

Computer scientists are abuzz over a fast new algorithm for solving one of the central problems in the field.

For this month’s puzzle, design a Sudoku square to figure out the likes and dislikes of four finicky friends.