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gravity
quantum gravity
How Gravity Is a Double Copy of Other Forces
An enigmatic connection between the forces of nature is allowing physicists to explore gravity’s quantum side.
quantum gravity
Quantum Mischief Rewrites the Laws of Cause and Effect
Spurred on by quantum experiments that scramble the ordering of causes and their effects, some physicists are figuring out how to abandon causality altogether.
2020 in Review
The Year in Physics
Featuring paradoxical black holes, room-temperature superconductors and a new escape from the prison of time.
Abstractions blog
A New Cosmic Tension: The Universe Might Be Too Thin
Cosmologists have concluded that the universe doesn’t appear to clump as much as it should. Could both of cosmology’s big puzzles share a single fix?
Q&A
The Physicist Who Slayed Gravity’s Ghosts
Claudia de Rham showed how theories of “massive gravity” could potentially get rid of the need for dark energy.
gravitational waves
How the Bits of Quantum Gravity Can Buzz
New calculations show how hypothetical particles called gravitons would give rise to a special kind of noise.
Abstractions blog
Why Gravity Is Not Like the Other Forces
We asked four physicists why gravity stands out among the forces of nature. We got four different answers.
quantum gravity
Black Hole Paradoxes Reveal a Fundamental Link Between Energy and Order
By chewing on the problems posed by “extremal” black holes, physicists have exposed a surprising and universal connection between energy and entropy.
mathematical physics
New Math Proves That a Special Kind of Space-Time Is Unstable
Einstein’s equations describe three canonical configurations of space-time. Now one of these three — important in the study of quantum gravity — has been shown to be inherently unstable.