black hole
Is the Universe finite or infinite? Is there infinity inside a black hole? Is space infinitely divisible or is there a shortest length? We talk to philosophers and physicists to find out. 
Find out how some black holes are bigger on the inside than they are on the outside. 
Finally we can be sure — black holes, those gravitational monsters that gobble up everything that gets too close to them, do exist.

Physicists have finally detected the gravitational waves they have been chasing for nearly 100 years. 
It's impossible not to be fascinated by black holes. Find out all you'd like to know about them with these articles, videos and podcasts. 
Rumours abound that physicists have detected gravitational waves produced by the merger of two black holes. 
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. 
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. 