String theory

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

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

By replacing black holes with fuzzballs — dense, star-like objects from string theory — researchers think they can avoid some knotty paradoxes at the edge of physics.

In his latest book, the Nobel Prize winner Steven Weinberg explores how science made the modern world, and where it might take us from here.

Researchers are on the trail of a mysterious connection between number theory, algebra and string theory.

If string theorists can show that their framework is the only consistent theory of quantum gravity, does that make it true even without tangible evidence?

New findings suggest that beneath the surface of quantum theory lies a vibrant string theory world where some matter corresponds to black holes in higher dimensions.

An interview with the Nobel Prize-winner David J. Gross on the confusing state of theoretical physics.