Author: The Plus Team

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

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

What are global coordinates?

Why the North Star tells you your latitude.

How longitude presented one of the greatest problems in history.

David Spiegelhalter's new book Sex by numbers takes a statistical peek into the nation's bedrooms. In this interview he tells us some of his favourite stories from the book. Read the article or watch the video!

It's not often you see a maths professor reduced to zero on stage and then stuffed into a bag. But this is exactly what happened to Marcus du Sautoy at the Science Museum — and by means of a mathematical argument at that. Only du Sautoy wasn't being himself of course. He was playing the role of X in the new play, X&Y.

In February this year we were lucky enough to interview Freeman Dyson at the Institute for Advanced Studies in Princeton, USA. Dyson is now 89 and still does physics every day in his first floor office at the Institute. Here is an edited version of our interview that we hope conveys his generous nature, wit and intellect.