What's up in

gravity

Distorted galaxies
Abstractions blog

A New Cosmic Tension: The Universe Might Be Too Thin

September 8, 2020

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?

Claudia de Rham portrait
Q&A

The Physicist Who Slayed Gravity’s Ghosts

August 18, 2020

Claudia de Rham showed how theories of “massive gravity” could potentially get rid of the need for dark energy.

An apple being jostled by gravitons
gravitational waves

How the Bits of Quantum Gravity Can Buzz

July 23, 2020

New calculations show how hypothetical particles called gravitons would give rise to a special kind of noise.

A falling apple.
Abstractions blog

Why Gravity Is Not Like the Other Forces

June 15, 2020

We asked four physicists why gravity stands out among the forces of nature. We got four different answers.

A black hole shooting thunderbolts.
quantum gravity

Black Hole Paradoxes Reveal a Fundamental Link Between Energy and Order

May 28, 2020

By chewing on the problems posed by “extremal” black holes, physicists have exposed a surprising and universal connection between energy and entropy.

Animation of black hole formation.
mathematical physics

New Math Proves That a Special Kind of Space-Time Is Unstable

May 11, 2020

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.

Animation of a black hole rotating.
Abstractions blog

Black Hole Singularities Are as Inescapable as Expected

December 2, 2019

For the first time, physicists have calculated exactly what kind of singularity lies at the center of a realistic black hole.

symmetry

The Simple Idea Behind Einstein’s Greatest Discoveries

June 26, 2019

Lurking behind Einstein’s theory of gravity and our modern understanding of particle physics is the deceptively simple idea of symmetry. But physicists are beginning to question whether focusing on symmetry is still as productive as it once was.

Art for "How Space and Time Could Be a Quantum Error-Correcting Code"
space-time

How Space and Time Could Be a Quantum Error-Correcting Code

January 3, 2019

The same codes needed to thwart errors in quantum computers may also give the fabric of space-time its intrinsic robustness.