free energy?
Jan. 7th, 2011 12:13 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
miriam_eIn the December 2010 issue of Scientific American on page 12, in the news section, there is a short piece titled "Hawking was right (probably)". It is about the possible detection of Hawking radiation, which is the radiation emitted at the boundary of a black hole, postulated by Stephen Hawking way back in 1974.
A little background first. It is thought that empty space is not truly empty -- that particles constantly and spontaneously bubble into existence in pairs then just as quickly nullify each other again. They don't name it in the article, but I believe this is what is known as "zero-point energy". A black hole's gravitational attraction is so powerful that even light can't escape, but because gravitational pull decreases with distance there will be a certain distance from the black hole, beyond which light can escape. This distance, which is the boundary between light being trapped or light escaping, is called the "event horizon". If a particle pair pops into existence at the event horizon and one particle moves in one direction, dropping into the black hole, and the other escapes in the other direction, then it will look like the black hole is giving off radiation. This is Hawking radiation.
Daniele Faccio created an artificial event horizon in some glass by changing the speed of light in the glass using an intense laser. If you shine intense light into certain materials it will change their refractive index. The refractive index of a material results from how it limits the speed of light. (For example, water has a high refractive index because light travels slowly through it.) Anyway, in some manner that I don't entirely understand yet, the alteration of the light-speed in the glass by using the laser supposedly creates a moving event horizon, apparently blocking photons from overtaking it. If a pair of photons are produced close enough to this event horizon then they will be separated instead of returning to equilibrium. Apparently Faccio detected photons that may have come from this.
The short article concentrates on what it means if they are right -- that this could confirm Hawking's prediction. But what interests me is that they may have found a way to tap zero-point energy. If so, that is a truly inexhaustible source of energy because it is quite literally getting energy out of nothing.
A little background first. It is thought that empty space is not truly empty -- that particles constantly and spontaneously bubble into existence in pairs then just as quickly nullify each other again. They don't name it in the article, but I believe this is what is known as "zero-point energy". A black hole's gravitational attraction is so powerful that even light can't escape, but because gravitational pull decreases with distance there will be a certain distance from the black hole, beyond which light can escape. This distance, which is the boundary between light being trapped or light escaping, is called the "event horizon". If a particle pair pops into existence at the event horizon and one particle moves in one direction, dropping into the black hole, and the other escapes in the other direction, then it will look like the black hole is giving off radiation. This is Hawking radiation.
Daniele Faccio created an artificial event horizon in some glass by changing the speed of light in the glass using an intense laser. If you shine intense light into certain materials it will change their refractive index. The refractive index of a material results from how it limits the speed of light. (For example, water has a high refractive index because light travels slowly through it.) Anyway, in some manner that I don't entirely understand yet, the alteration of the light-speed in the glass by using the laser supposedly creates a moving event horizon, apparently blocking photons from overtaking it. If a pair of photons are produced close enough to this event horizon then they will be separated instead of returning to equilibrium. Apparently Faccio detected photons that may have come from this.
The short article concentrates on what it means if they are right -- that this could confirm Hawking's prediction. But what interests me is that they may have found a way to tap zero-point energy. If so, that is a truly inexhaustible source of energy because it is quite literally getting energy out of nothing.