What's up in

# gravity

## Latest Articles

### How Our Reality May Be a Sum of All Possible Realities

Richard Feynman’s path integral is both a powerful prediction machine and a philosophy about how the world is. But physicists are still struggling to figure out how to use it, and what it means.

### She Turns Fluids Into ‘Black Holes’ and ‘Inflating Universes’

By using fluids to model inaccessible realms of the cosmos, Silke Weinfurtner is “looking for a deeper truth beyond one system.” But what can such experiments teach us?

### Black Hole's Orbiting Ring of Light Could Encrypt Its Inner Secrets

Physicists have discovered that the ring of photons orbiting a black hole exhibits a special kind of symmetry, hinting at a deeper meaning.

### Mass and Angular Momentum, Left Ambiguous by Einstein, Get Defined

Surprising as it may sound, 107 years after the introduction of general relativity, the meanings of basic concepts are still being worked out.

### Where Do Space, Time and Gravity Come From?

Einstein’s description of curved space-time doesn’t easily mesh with a universe made up of quantum wavefunctions. Theoretical physicist Sean Carroll discusses the quest for quantum gravity with host Steven Strogatz.

### Massive Black Holes Shown to Act Like Quantum Particles

Physicists are using quantum math to understand what happens when black holes collide. In a surprise, they’ve shown that a single particle can describe a collision’s entire gravitational wave.

### In Search of Cracks in Albert Einstein’s Theory of Gravity

Celia Escamilla-Rivera is combining large data sets with supercomputers to test general relativity against its little-known competitors.

### 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 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.