Could there be more than three?

A possible way of resolving the greatest problem of physics.

Open door #1 and scroll through our changing understanding of gravity...

To celebrate the recent centenary of the first major test of Einstein's general theory of relativity, we look back over how our picture of gravity has changed.

David Tong explains one of the most important equations in science.

A hundred years ago, on 25 November 1915, Einstein first presented his general theory of relativity. We explore this famous theory and what it says about the world we live in.

Pau Figueras explains how Einstein's theories predicted the existence of black holes, and how to describe them mathematically.

Small, dark, and very hard to see. This and far more indepth answers to every question you ever wanted to ask about black holes.

To celebrate the centenary of the general theory of relativity we asked physicist David Tong to explain the theory and the equation that expresses it. Watch the video or read the article!

Read about the rocky road to one of Einstein's greatest achievements: the general theory of relativity, which celebrates its centenary this year.

General relativity, Einstein's rise to international stardom, and his legacy.

To celebrate the release of more English translations of Einstein's papers, we revisit one of his previously unknown models of the Universe.