Now here is an interesting experimental result. A team at the Israel Institute of Technology claims to have created a sonic “black hole”. “One of the many curious properties of Bose Einstein Condensates (BECs) is that the flow of sound through them is governed by the same equations that describe how light is bent by a gravitational field. […] –in theory, physicists can reproduce with sound and BECs, [whatever]
gravity has with light.”
In fact, this lab claims to have created an event horizon that is the acoustic equivalent to the light event horizon of a black hole. Having an event horizon in the lab can lead to tests of quantum gravity by analogy. For example, it may in time provide the first experimental confirmation of some of Stephen Hawking’s work.
One reason why sonic black holes are so highly prized is that they ought to produce Hawking radiation. Quantum mechanics predicts that pairs of “virtual” phonons with equal and opposite momentum ought to be constantly springing in and out of existence in BECs.
If one of this pair were to cross the event horizon, it would be sucked into the black hole, never to escape. The other, however, would be free to go on its way. This stream of escapees would be the famous, but as yet unobserved, Hawking radiation.