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Hawking Radiation Mimicked In the Lab
Annanag writes *Nothing* escapes a black hole, right? Except 40 years ago Stephen Hawking threw a spanner in the works by suggesting that, courtesy of quantum mechanics, some light particles can actually break free of a black hole's massive pull. Then you have the tantalizing question of whether information can also escape, encoded in that so-called 'Hawking radiation'. The only problem being that no one has ever been able to detect Hawking radiation being emitted from a black hole. BUT a physicist has now come closer than ever before to creating an imitation of a black hole event horizon in the lab, opening up a potential avenue for investigating Hawking radiation and exploring how quantum mechanics and general relativity might be brought together.
This stuff isn't my strong suit at all, but I'm having a hard time grasping how sound waves can behave like subatomic particles in this way.
Pairs of sound waves pop in and out of existence in a laboratory vacuum, mimicking particle-antiparticle pairs in the vacuum of space.
Sound is a wave through some medium, so how can they pop into existence in a vacuum? Are particles of some kind (and what are they? Hydrogen atoms? Helium?) popping into existence long enough for them to physically interact with one another so a physical wave can propagate from one particle to another before they pop back out of existence, and thus "sound waves" are appearing?
All this is pretty amazing to me, but the amount of complexity involved (using dual event horizons to reflect the waves back and forth to amplify the audio signal because its so weak, etc) sure would leave a lot of room to screw something up along the way. Seems the signal to noise ratio would be pretty bad.
Better known as 318230.
I never did get this... Hawking radiation doesn't "Escape" a black hole. In empty space, there is a constant seething foam of particle-antiparticle pairs that get created all the time. Normally these pairs immediately collide with one another, or their neighbors, and obliterate each other so they are mostly undetectable. With a blackhole you have an event horizon. One side of which is inescapable, the other side is escapable. It stands to reason, that along this line these particle-antiparticle pairs would get created with one inside the horizon and the other outside of it. Resulting in a net increase in the number of particles created. Nothing "Escaped" at all.