Black holes could be created in the laboratory, claim physicists from Sweden and Scotland. Their calculations show that, thanks to some recent advances in condensed matter physics, it is theoretically possible to create an optical black hole to attract and trap specific colours of light in just the same way as an astronomical black hole attracts and consumes matter.
The researchers unearthed a 1923 paper in which Walter Gordon, starting from Einstein's idea of gravity mediated by changes in the metric of space and time, realized that space-time is effectively a medium and that consequently, any moving dielectric medium acts on light as an effective gravitational field. However, to see effects as dramatic as a black hole, the velocity of light in the medium must be low compared with the velocity of the medium.
Recent results from US physicists working with Bose-Einstein condensates (BEC) suggest that this is feasible: quantized vortices have been generated in a BEC of rubidium atoms, while light has been slowed down inside a BEC to a mere 50 cm/s, and even 1 cm/s may soon be achieved.
A BEC vortex, swirling faster than the light can move, would drag the light into its centre, where it would eventually be absorbed by the gas. An event horizon - a radius of no return - would form about the vortex, just like the Schwarzschild radius of an astronomical black hole.
Then, some spectacular effects of general relativity could be seen in a terrestrial laboratory, perhaps demonstrating an analogue of Hawking radiation from black holes (obscured by the cosmic background radiation and so far never observed in astronomy) and even exploring prototype theories of quantum gravity.
However, the experimental difficulty in generating sufficiently fast and durable BEC vortices means that a home-grown black hole is probably still about five years away. AIP