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AnonTechie writes:

If there is a “holy grail” to be found in modern astrophysics, it probably has something to do with finding out what’s going on inside of black holes. Since no light escapes from their event horizons, studying their insides directly is impossible. As if that wasn’t bad enough, our best theories tend to break down inside the event horizon, limiting our ability to study them even theoretically with present models.

Despite all that, there are ways to get at the behavior of black holes. A recent line of work is approaching the problem in a different way—by analogy. Rather than trying to observe real black holes or trying to simulate them mathematically, researchers are constructing analogs of black holes. These constructions can be observed in a lab, right here on Earth.

Of course, scientists have no way of creating an actual gravitational singularity on a table-top, so they had to rely on the next best thing. The essence of a black hole is that it has an event horizon—a point of no return from which no light can escape. By analogy, in a fluid, there can be a point of no return for sound waves. If, for example, the fluid is moving faster than the speed of sound, no sound can outrun the fluid to escape in the opposite direction. That’s the basic idea behind a new experiment published in the journal Nature Physics (abstract) —an experiment that apparently makes a Hawking radiation laser out of a sonic black hole.

[Additional Coverage]: http://www.universetoday.com/115307/hawking-radiation-replicated-in-a-laboratory/