For how would a man benefit to gain the whole universe but destroy its mass?
Stephen Hawking has also been on the losing end of some other physics-related wagers, notably two involving black holes.
In 1975, cosmologist Stephen Hawking bet fellow cosmologist Kip Thorne a subscription to Penthouse magazine for Thorne against four years of Private Eye for him that Cygnus X-1 would turn out not to be a black hole. It was, so Hawking lost.
In 1997 Stephen Hawking and Kip Thorne made a bet with John Preskill on the ultimate resolution of the apparent contradiction between Hawking radiation resulting in loss of information, and a requirement of quantum mechanics that information cannot be destroyed. Hawking and Thorne bet that information must be lost in a black hole; Preskill bet that it must not...The stake was an encyclopaedia of the winner's choice, from which "information can be recovered at will". Hawking conceded the bet in 2004, giving a Baseball encyclopaedia to John Preskill.
Of course, Hawking won
his biggest battle against all odds:
The diagnosis of motor neurone disease came when Hawking was 21 ((back in the early 60's)), shortly before his first marriage, and doctors said he would not survive more than two or three years.
Hopefully Mr. Hawking will continue to obey the laws of physics for a long time so that he is able to continue placing wagers... win or lose.