Theoretical physics

String theorists elide a paradox about black holes by extinguishing the walls of fire feared to surround them.

A controversial new paper argues that universes with dark energy profiles like ours do not exist in the “landscape” of universes allowed by string theory.

A quickly closed loophole has proved that the “great smoky dragon” of quantum mechanics may forever elude capture.

By squeezing fluids into flat sheets, researchers can get a handle on the strange ways that turbulence feeds energy into a system instead of eating it away.

Scientists seek a single description of reality. But modern physics allows for many different descriptions, many equivalent to one another, connected through a vast landscape of mathematical possibility.

In an era when untestable ideas such as the multiverse hold sway, Michela Massimi defends science from those who think it hopelessly unmoored from physical reality.

Decades after physicists happened upon a stunning mathematical coincidence, researchers are getting close to understanding the link between two seemingly unrelated geometric universes.

Gravitational waves have opened up new ways to test the properties of black holes — and Einstein’s theory of gravity along with them.

The renowned British physicist, who died at 76, left behind a riddle that could eventually lead his successors to the theory of quantum gravity.