Physicists create 'black hole for sound'
http://www.newscientist.com/article/dn1 ... sound.html
Now, an acoustic black hole is a fascinating idea in itself. But it is being used to experimentally model gravity-induced black holes, as conjectured by Hawking. Isn't it significant that, in producing a black hole of any sort, the experimenters had to use electromagnetism?
The team cooled 100,000 or so charged rubidium atoms to a few billionths of a degree above absolute zero and trapped them with a magnetic field. Using a laser, the researchers then created a well of electric potential that attracted the atoms and caused them to zip across the well faster than the speed of sound in the material.
This setup created a supersonic flow that lasted for some 8 milliseconds, fleetingly forming an acoustic black hole capable of trapping sound.
Isn't this a huge concession to plasma cosmology?
I wonder if any of that Hawking radiation they're looking for will turn up.
