Tickets for Stephen Hawking's public birthday symposium this Sunday 8th of January have long been sold out, but you can join the fun by watching the live webcast here on Plus. It's for a general audience and the speakers are Martin Rees, Saul Perlmutter (winner of last year's Nobel Prize in Physics), Kip Thorne and Stephen Hawking himself, who will be the final speaker of the day. The programme starts at 2pm — here's the time table. Tune in with Plus!