Black Hole is a region in space where the gravitational force is so strong that nothing can leave the region. 42 year ago, Stephen Hawking predicted that black holes shrink because they emit electromagnetic radiation. Since then, this prediction was nothing but a theory as the radiation is too weak to observe using the technologies available today. But as science evolves, the mysteries that involve black holes begin to be revealed. What Stephen Hawking hypostasized back in 1974, is confirmed after all these years. A survey published recently in Nature Physics confirmed the theory and showed that, in some way, it is possible to escape the from the black hole.
As indicated by Wired, researchers at Technion - Israel Institute of Technology, led by scientist Jeff Steinhauer, created a acoustic black hole from which sound rather than light cannot escape - to observe Hawking-like radiation. The observation was performed in a Bose-Einstein condensate – a quantum state of matter where a clump of super-cold atoms behaves like a single atom. It took Jeff Steinhauer seven years to perfect this technique.
The acoustic black hole was developed in a Bose-Einstein condensate - a state in which the boson particles are cooled to near absolute zero. Then, in a quantum state, scientists manipulated this conglomeration of cold atoms through a magnetic trap and, finally, to turn it in the acoustic black hole, using a laser of large diameter. You can find all the technical details here.
In the experiment, Steinhauer studied how particles behave on the edge of his “black hole” – the equivalent of an event horizon, which is essentially the “point of no return” in spacetime, beyond which events cannot affect an outside observer of an analogue black hole. He found that pairs of phonons – particles of sound – appear spontaneously in the void at the event horizon. One of the phonons travels away from the black hole as Hawking radiation, and the other partner phonon falls into the black hole.
We observe spontaneous Hawking radiation, stimulated by quantum vacuum fluctuations, emanating from an analogue blackhole in an atomic Bose–Einstein condensate.
...This confirms Hawking’s prediction regarding black hole thermodynamics.
Jeff Steinhauer, Department of Physics, Technion—Israel Institute of Technology, Israel
If you do not know, the event horizon is a commonly used physics terms that represent the point of no return - it is a theoretical border around a black hole in which the force of gravity is so strong that nothing escapes, not even light. This is because the speed of light, for example, is below the exhaust velocity of the black hole.
Image source: Nasa
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