In 1969, Roger Penrose proposed a method to extract rotational energy of a rotating black hole, and suggested that an advanced civilization could achieve it by lowering and then releasing a mass from a structure that is co-rotating with the black hole. The process would occur in the region just outside the event horizon, called the ergosphere, where frame-dragging is at its strongest, being able to tear apart an object; one part would enter the event horizon while the remaining one would be accelerated outwards with an additional impulse given by the rotational energy of the black hole. The excess energy calculated by Penrose was estimated to be 21 percent more than the incoming energy.
The process is brilliantly explained in this video:
Inspired by Penrose’s idea, Yakov Zel’dovich predicted in 1971 that quantum fluctuations and classical electromagnetic waves reflected from a rotating absorbing cylinder would gain energy and be amplified. Though the concept is key to understanding that black holes may amplify quantum fluctuations, it could not be verified experimentally since the cylinder rotation rate must be larger than the incoming wave frequency, making it very challenging when using electromagnetic waves.
However, these conditions can be satisfied with acoustic waves, as the team of physicists from the University of Glasgow’s School of Physics and Astronomy in Scotland showed by devising an experiment based on Zel’dovich’s work in which instead of using light waves, they used sound waves. The experimental set-up consisted on a ring of speakers and tubes that guide the sound directly onto a rotating foam disk. The ring of speakers was set up to introduce a twist in the sound waves, analogous to the twisted light in Zel’dovich’s experiment. Here, the ‘black hole’ is the rotating sound absorber made from a foam disc. On the other side of the disc, an array of microphones would detect the sound waves after they had passed through the disc; the shift in pitch and amplitude in the sound waves that passed through the disc would verify the Penrose process.
In these experiments they show that low-frequency acoustic modes with orbital angular momentum (OAM) are transmitted through the absorbing rotating disk and amplified by up to 30% or more when the disk rotation rate satisfies the Zel’dovich condition for amplification (from an absorbing, rotating body), which depends on 1) the incident wave frequency ω, 2) the order l of the OAM, and 3) the rotation rate Ω of the absorber. When the condition ω- l Ω < 0 is satisfied, the absorption changes sign and the rotating medium acts as an amplifier. Outgoing waves then have an increased amplitude and therefore, they extracted energy from the rotational energy of the body, just like Penrose’s proposal.
As the authors of this study say, “These experiments address an outstanding problem in fundamental physics and have implications for future research into the extraction of energy from rotating systems”. With this brilliant experiment, Penrose’s prediction of an advanced civilization capable of extracting energy from Black holes, no longer seems science fiction!
Highlights:
This brilliant experiment describes a mechanism analogous to the one Nassim Haramein used to design his Harmonic Flux Resonator (HFR), in which the rotation of electromagnetic fields would create a density gradient that allows interaction or coupling with the quantum vacuum. Based on the hypothesis that space is a superfluid, the HFR is a magneto-hydrodynamic device that has managed to generate a certain amount of coherent gradient in a localized region of space, producing gravitational effects, among other remarkable qualities.
This study, together with Haramein’s work, recalls Dr. Eugene Podkletnov’s experiments and the gravitational effects encountered using rotating superconducting discs. This empirical evidence for a device that can modify a localized gravitational field through spin, came from his team in 1992, and the results on gravitationally induced weight reduction were published in an article in Journal Physica C: Superconductivity. The effect was produced by a superconducting ceramic disk cooled below 77 degrees Kelvin, which levitated when spun at approximately 5000 rpm.
More at:
https://www.nature.com/articles/s41567-020-0944-3
https://www.sciencealert.com/an-experiment-has-just-demonstrated-how-energy-could-be-extracted-from-a-black-hole
