Julian Barbour. Portrait of the English theorist on time and astrophysics, Julian Barbour (born 1937). Barbour studied mathematics at Cambridge University, England, before commencing a PhD on astrophysics in Munich. In 1968 he completed a PhD on the origins of relativity in Cologne. Barbour theorises that time is an artefact born of the observation of change. He argues that the quantum universe is static, and exists as a set of states independent of time, governed only by their probability. Our notion of time arises from our observation of these states. His published works include Absolute or Relative Motion (1989) and The End of Time (1999). Photographed in 2000.