Dr Jonathan Pritchard talks to BBC Two

Dara O Briain and the team go on a journey through time to discover what it is and how to get more of it: 'The age of the universe is something scientists have wrestled with for a long time. Just last year after centuries of revising the number upwards, they decided the number was in fact 13.798 billion years. We know quite a bit about what has happened in those 14 billion odd years, but there's a gap known as the cosmic dark ages. Mark has been to see if we can shed some light on the subject' [with] Dr Jonathan Pritchard [Physics] who has dedicated his career to working out what happened to the universe in its formative years.