"Black holes are staples of science fiction and many think astronomers have observed them indirectly. But according to a physicist at the Lawrence Livermore National Laboratory in California, these awesome breaches in space-time do not and indeed cannot exist."

In general relativity, there is no such thing as a 'universal time' that makes clocks tick at the same rate everywhere. Instead, gravity makes clocks run at different rates in different places. But quantum mechanics, which describes physical phenomena at infinitesimally small scales, is meaningful only if time is universal; if not, its equations make no sense.

This problem is particularly pressing at the boundary, or event horizon, of a black hole. To a far-off observer, time seems to stand still here. A spacecraft falling into a black hole would seem, to someone watching it from afar, to be stuck forever at the event horizon, although the astronauts in the spacecraft would feel as if they were continuing to fall. "General relativity predicts that nothing happens at the event horizon," says Chapline.

However, as long ago as 1975 quantum physicists argued that strange things do happen at an event horizon: matter governed by quantum laws becomes hypersensitive to slight disturbances. "The result was quickly forgotten," says Chapline, "because it didn't agree with the prediction of general relativity. But actually, it was absolutely correct."

This strange behaviour, he says, is the signature of a 'quantum phase transition' of space-time. Chapline argues that a star doesn't simply collapse to form a black hole; instead, the space-time inside it becomes filled with dark energy and this has some intriguing gravitational effects.

Now, if I only had the competency to evaluate this properly, I'd be flying ..