Stephen Hawking marks 70th birthday with speech to leading cosmologists

‘Look up at the stars and not down at your feet,’ says scientist, unable to attend symposium in person due to ill health

Alok Jha, science correspondent, Sunday 8 January 2012 14.34 EST Article history

Stephen Hawking, 70, revealed his schoolfriends made a bet that he 'would never come to anything'. Photograph: David Parry/PA