Physics

If a theory can’t be tested, is it still science?

Scientists are homing in on a warning signal that arises in complex systems like ecological food webs, the brain and the Earth’s climate. Could it help prevent future catastrophes?

The physicist Gabriela González is on the cusp of finding the first direct evidence of gravitational waves — soundlike wobbles in space-time produced by black holes and their kin.

Nima Arkani-Hamed is championing a campaign to build the world’s largest particle collider, even as he pursues a new vision of the laws of nature.

Einstein refused to believe in the inherent unpredictability of the world. Is the subatomic world insane, or just subtle?

In the drive to safeguard data from future quantum computers, cryptographers have stumbled upon a thin red line between security and efficiency.

The physicist James Bullock explains how a complicated “dark sector” of interacting particles may illuminate some puzzling observations of the centers of galaxies.

Did the minerals on our planet arise in a predictable fashion, or did they result from chance events? The answers could eventually help scientists identify planets likely to harbor life.

Explore the deepest mysteries at the frontier of fundamental physics, and the most promising ideas put forth to solve them.