Does time exist?

Was our universe born from a Big Bang, or from a Big Bounce triggered by a former universe imploding?

Is this the only universe, or are there infinite ones, all expanding in parallel and out of sight of each other?

These are just some of the questions that were tackled by world-renowned physicists Carlo Rovelli and Christophe Galfard when they came to the Intelligence Squared stage and were joined in conversation by BBC science star Helen Czerski.

Theoretical physics deals with matters at the very limits of human understanding. Einstein was once prompted to tell a student: ‘If you have understood me, then I haven’t been clear.’ In the face of this complexity, Rovelli and Galfard have found a way of explaining the mysteries of physics that has made them the most popular science communicators in their countries. In Italy, Rovelli has consistently outsold Fifty Shades of Grey with his book Seven Brief Lessons on Physics, which last year became a Sunday Times bestseller. Galfard — who gained his PhD as Stephen Hawking’s graduate student — won France’s Science Book of the Year for his book on the cosmos The Universe in Your Hand.

There could hardly be a better moment for Rovelli and Galfard to shed light on the revelations that physics is making about the universe. Technology is allowing us to observe for the first time in reality phenomena that have until now only been suggested in theory. Earlier this year, the LIGO observatory in the US made the first ever detection of gravitational waves — 100 years after Einstein predicted the existence of these ripples in spacetime. Galfard describes the discovery as the beginning of ‘a totally new era for mankind’. He states: ‘We haven’t lived through such a thing since the advent of Galileo’s telescope, which changed the whole face of the universe. This is history in the making. Mankind will probably remember this in 1,000 years.’ Being able to see these waves, Galfard and Rovelli explained, will let us peer into the very origins of matter and time.