Carlos Frenk, Ogden Professor of Computational Cosmology at the University of Durham, studies the universe, but not by spending nights looking out at the dark skies through telescopes. Rather he creates the cosmos on computers. He is also one of the Gang of Four of astrophysics who thirty years ago came up with one of the most important theories in their field. They worked out that the universe is full of cold dark matter. In 2011 Carlos Frenk and his colleagues were awarded the Gruber prize, one of the leading accolades in astronomy, for their theory.

Carlos Frenk discusses this mysterious missing mass, which is still mysterious and missing, with Jim al-Khalili. They talk about modelling the universe inside computers, and how Carlos persuaded his university to hire the architect Daniel Liebskind to design a building for creative thinking about the cosmos.