10:17 13 March 2006
NewScientist.com news service
Nearly all of the information that falls into a black hole escapes back out, a controversial new study argues. The work suggests that black holes could one day be used as incredibly accurate quantum computers - if enormous theoretical and practical hurdles can first be overcome.
Black holes are thought to destroy anything that crosses a point of no return around them called an "event horizon". But in the 1970s, Stephen Hawking used quantum mechanics to show black holes do emit radiation, which eventually evaporates them away completely.
Originally, he argued that this "Hawking radiation" is so random that it could carry no information out about what had fallen into the black hole. But this conflicted with quantum mechanics, which states that quantum information can never be lost. Eventually, Hawking changed his mind and in 2004 famously
conceded a bet, admitting that black holes do not destroy information.