Quantum gravity

Encouraged by successes in understanding black holes, theoretical physicists are applying what they’ve learned to whole universes. What they’re finding has them questioning fundamental assumptions about how physics ought to be done.

Has the secret to understanding gravity been hiding in plain sight for nearly 50 years?

The theoretical physicist and best-selling author finds inspiration in politics and philosophy for rethinking space and time.

According to Einstein’s theory of gravity, black holes have only a small handful of distinguishing characteristics. Quantum theory implies they may have more. Now an experimental search finds that any of this extra ‘hair’ has to be pretty short.

A new argument explores how the growth of disorder could cause massive objects to move toward one another. Physicists are both interested and skeptical.

Black hole and Big Bang singularities break our best theory of gravity. A trilogy of theorems hints that physicists must go to the ends of space and time to find a fix.

Quantum gravity could help physicists unite the currently incompatible worlds of quantum mechanics and gravity. In this episode, Monika Schleier-Smith discusses her pioneering experimental approach, using laser-cooled atoms to explore whether gravity could emerge from quantum entanglement.

Physicists hope that understanding the churning region near singularities might help them reconcile gravity and quantum mechanics.

The reference frames from which observers view quantum events can themselves have multiple possible locations at once — an insight with potentially major ramifications.