By Stephen Hawking (University of Cambridge)
By Storm Dunlop, Wil Tirion, Royal Observatory Greenwich, Collins Astronomy
By Carlo Rovelli, Erica Segre, Simon Carnell
By John Bally (University of Colorado, Boulder), Bo Reipurth (University of Hawaii, Manoa)
By Christopher R. Kitchin
By Sobel, Dava
By Professor Emeritus John W Moffat (University of Toronto)
By jan jagodzinski
By C. Carter
By M. Naseem
By Rachelle Winkle-Wagner, Cheryl A. Hunter, D. Hinderliter Ortloff, Kenneth A. Loparo
By J. Beier
By T. Csordas
By M. Foote
By Richard Panek
By P. Manning
By Gerald North
By Stephen Hawking
By Laurence A. Marschall
By Arthur I. Miller
By Marcia Bartusiak
By Colin Stuart
By Martin Rees
By Giles Sparrow
By Fionn Murtagh, Andre Heck
By Lee Billings
By Brian Knapp