What's up in

# gravity

## Latest Articles

### In a ‘Dark Dimension,’ Physicists Search for the Universe’s Missing Matter

An idea derived from string theory suggests that dark matter is hiding in a (relatively) large extra dimension. The theory makes testable predictions that physicists are investigating now.

### A Century Later, New Math Smooths Out General Relativity

Mathematicians prove a theorem that illuminates the geometry of universes with tiny amounts of mass.

### Math Proof Draws New Boundaries Around Black Hole Formation

For a half century, mathematicians have tried to define the exact circumstances under which a black hole is destined to exist. A new proof shows how a cube can help answer the question.

### The Physicist Who’s Challenging the Quantum Orthodoxy

For decades, physicists have struggled to develop a quantum theory of gravity. But what if gravity — and space-time — are fundamentally classical?

### An Enormous Gravity ‘Hum’ Moves Through the Universe

Astronomers have found a background din of exceptionally long-wavelength gravitational waves pervading the cosmos.

### The Physicist Who Glues Together Universes

Renate Loll has helped pioneer a radically new approach to quantum gravity. She assumes that the fabric of space-time is a blend of all possible fabrics, and she has developed the computational tools needed to calculate the far-reaching implications of that assumption.

### Are There Reasons to Believe in a Multiverse?

Several areas of physics suggest reasons to think that unobservable universes with different natural laws could lie beyond ours. The theoretical physicist David Kaplan talks with Steven Strogatz about the mysteries that a multiverse would solve.

### New Proof Finds the ‘Ultimate Instability’ in a Solar System Model

For the first time, mathematicians have proved that planetary orbits in a solar system will always be unstable.

### How Will the Universe End?

Big Freeze, Big Rip, Big Crunch, Bounce or vacuum decay? Steven Strogatz speaks with theoretical cosmologist Katie Mack about the five ways that scientists think the universe could come to an end.