Black-Hole Laser Edges Closer to Testing Hawking
In a laboratory in Scotland, a revolutionary kind of laser is taking shape – the first one to be made out of an artificial black hole. Once complete, the device could help confirm mounting evidence that real black holes, despite their name, emit light. A black-hole laser could also find practical uses in devices that probe a material’s properties without damaging it.
At the heart of such a laser is a phenomenon that Stephen Hawking predicted in the 1970s, and that physicists have been hunting ever since. Although not even light can escape their gravity, Hawking calculated that black holes should nonetheless emit a faint glow, now called Hawking radiation. This is a consequence of quantum theory, which says that a vacuum is not truly empty, but fizzes with fleeting pairs of particles and their antimatter counterparts. Normally, these pairs rapidly annihilate and disappear again, but if a pair of photons pops out too close to a black hole, one falls in – and the other escapes.