By J.G. Taylor
By John Archibald Wheeler
By Roger Penrose
By David Darling
By Lawrence M. Krauss
By John D. Barrow
By Leon M. Lederman, Christopher T. Hill
By Joseph Silk (, Savilian Professor of Astronomy, University of Oxford)
By Carl Sagan
By Stephen Hawking (University of Cambridge)
By Frank Close (Professor of Theoretical Physics and Fellow of Exeter College, University of Oxford)
By George Musser
By Tom Kerss, Royal Observatory Greenwich, Collins Astronomy
By Frank Wilczek (Author)
By Lisa Randall
By Dr Sten Odenwald
By Michael Wall
By Giles Sparrow
By Ritchie, Rob
By Priyamvada Natarajan
By Neil Gunn
By Vincent Cronin
By David Christian
By Noel Edmonds
By P. C. W. Davies
By Michio Kaku
By Colin A. Ronan
By Ian Ridpath, Martin J. Rees
By Dr Gordon Strachan