Editing Cygnus X-1 (section)

==Stephen Hawking and Kip Thorne==
[[File:2259 Black Hole 1280 English.jpg|thumb|NASA's "Galaxy of Horrors" poster for Cygnus X-1<ref name=devoured/>]]
Cygnus&nbsp;X-1 was the subject of a bet between physicists [[Stephen Hawking]] and [[Kip Thorne]], in which Hawking bet against the existence of black holes in the region. Hawking later described this as an "insurance policy" of sorts. In his book ''A Brief History of Time'' he wrote:<ref name=hawking1988/>
{{bquote|This was a form of insurance policy for me. I have done a lot of work on black holes, and it would all be wasted if it turned out that black holes do not exist. But in that case, I would have the consolation of winning my bet, which would win me four years of the magazine ''[[Private Eye]]''. If black holes do exist, Kip will get one year of ''[[Penthouse (magazine)|Penthouse]]''. When we made the bet in 1975, we were 80% certain that Cygnus&nbsp;X-1 was a black hole. By now [1988], I would say that we are about 95% certain, but the bet has yet to be settled.}}
According to the updated tenth-anniversary edition of ''A Brief History of Time'', Hawking has conceded the bet<ref name=hawking1998/> due to subsequent observational data in favor of black holes. In his own book ''[[Black Holes and Time Warps]]'', Thorne reports that Hawking conceded the bet by breaking into Thorne's office while he was in [[Russia]], finding the framed bet, and signing it.<ref name=thorne1994/> While Hawking referred to the bet as taking place in 1975, the written bet itself (in Thorne's handwriting, with his and Hawking's signatures) bears additional witness signatures under a legend stating "Witnessed this tenth day of December 1974".<ref name=wager/> This date was confirmed by Kip Thorne on the January&nbsp;10, 2018 episode of [[Nova (American TV series)|''Nova'']] on [[PBS]].<ref name=apocalypse/>