Early in his career, Hawking described black holes and claimed they break all physical laws. Since then they have been 'found' at the centre of galaxies. Now leading cosmologists, Hawking amongst them, doubt they exist. Are black holes a fantasy? If so, much is at stake including relativity and the origin of the universe.
Theoretical physicist Laura Mersini-Houghton, author of The Perfect Theory Pedro Ferreira and former Royal Astronomical Society president Michael Rowan-Robinson explore beyond black holes.