Scientists create black holes in a lab

Washington, Feb 14 : A research team from the University of St Andrews, UK, claims to have used laser lights to simulate black holes in their laboratory.

Ulf Leonhardt and his colleagues accomplished this feat by firing lasers down an optical fibre, exploiting the fact that different wavelengths of light move at different speeds within an optical fibre.

They first shot a relatively slow moving laser pulse through the fibre, and then sent a faster "probe wave" chasing after it.

The first pulse distorts the optical properties of the fibre simply by travelling through it. This distortion forces the speedy probe wave to slow down dramatically when it catches up with the slower pulse and tries to move through it.

In fact, the probe wave becomes trapped and can never overtake the pulse's leading edge, which effectively becomes a black hole event horizon, beyond which light cannot escape.

This "laser black hole" could allow physicists to examine what happens to light on both sides of an event horizon.

Cosmologists have already worked out exactly how light should change frequency as it approaches an event horizon - from the outside or the inside of a black hole - and sure enough, the team observed exactly these shifts in their experiment.

It should also be possible to use the artificial event horizon to help test whether anything can escape from a black hole.

In the 1970s, Stephen Hawking predicted that hot black holes could radiate particles, dubbed Hawking radiation, but it's tough to check this using telescopes, because they'd be swamped by noise.

Now, the research team has calculated that their laser black hole shares this property, and that it will "radiate" photons if it heats up to about 1000 degrees centigrade.

According to Ray Rivers at Imperial College London, "They've done some clever stuff to give us a chance of seeing Hawking radiation for the first time."

ANI