By John Gribbin
By Martin Rees
By Storm Dunlop, Wil Tirion, Royal Observatory Greenwich, Collins Astronomy
By Chris Clarke
By Jorge Cham, Daniel Whiteson
By Robert M. Hazen
By Dr Gordon Strachan
By Ian Ridpath, Martin J. Rees
By Stephen Hawking (University of Cambridge)
By Colin A. Ronan
By Michio Kaku
By P. C. W. Davies
By John D. Barrow (Cambridge University)
By Tom Kerss, Royal Observatory Greenwich, Collins Astronomy
By Frank Wilczek (Author)
By Lisa Randall
By Dr Sten Odenwald
By Michael Wall
By Michael Brooks, Rick Edwards
By Giles Sparrow
By Kenneth R. Lang
By Neil Gunn
By Noel Edmonds
By David Christian
By John Michell
By Vincent Cronin
By Ritchie, Rob
By Richard Kent
By Prof Keith Smith (University of Stirling, UK), keith smith