Physicists have successfully recreated a theoretical phenomenon related to black holes in the laboratory. This experiment opens new perspectives for understanding these mysterious cosmic objects.
In 1972, William Press and Saul Teukolsky theorized a concept nicknamed the 'black hole bomb'. Their idea was based on the exponential amplification of waves by a rotating black hole, enclosed in a system of mirrors. Nearly fifty years later, an international team has experimentally validated this theory.
The experiment builds on the work of Roger Penrose and Yakov Zel'dovich. The former had imagined in 1969 a way to extract energy from a rotating black hole. The latter discovered in 1971 that a rotating object could amplify electromagnetic waves under certain conditions, an effect now known as the Zel'dovich effect.
To reproduce this effect, the researchers used an aluminum cylinder rotating at high speed. Surrounded by metal coils, this setup allowed the observation of the amplification of a weak magnetic field, thus confirming the phenomenon of superradiance.
The team pushed the experiment to the point of causing instability, generating spontaneously amplified waves. This crucial step sometimes led to the destruction of components, and thus the experiment, demonstrating the intensity of the forces at play. The results, although spectacular, still need to be validated and published in a scientific journal.
This breakthrough is not limited to black holes. It illustrates a universal principle applicable to various rotating systems. The implications span astrophysics, thermodynamics, and quantum theory.
The researchers hope their model will help better understand the rotation of black holes.
What is superradiance?
Superradiance is a phenomenon where a rotating object amplifies the waves that reach it. This concept, initially applied to black holes, shows how energy can be extracted from these cosmic objects.
When a wave encounters a rotating black hole, part of its energy is reflected with greater amplitude. This process depends on the black hole's rotation speed and the properties of the incident wave.
In the laboratory, superradiance was simulated using a rapidly rotating metal cylinder. The results confirm that wave amplification is possible without the presence of a black hole, thus broadening the scope of this phenomenon.
This discovery could have implications in various fields, particularly in the development of new technologies based on the amplification of electromagnetic waves.
How does the Zel'dovich effect work?
The Zel'dovich effect describes the amplification of electromagnetic waves by a rotating object. Predicted in 1971, it is based on the idea that rotation can transfer energy to waves.
For this effect to occur, the object's surface must move faster than the phase velocity of the incident wave. This condition is crucial for shifting from absorption to amplification.
In the recent experiment, a rotating cylinder served as a model for a black hole. The researchers observed that the reflected magnetic field was more intense than the incident field, thus validating the Zel'dovich effect.