14 DAY TRIAL // Most people know that black holes exist at the core of massive galaxies, where they exert their huge gravitational pull on surrounding matter. But what is generally less known is the fact that black holes can also be produced artificially, although these objects only act like their cosmic counterparts to some limited degree. In a recent set of experiments, Chinese researchers managed to construct such a structure that only functions for microwave wavelengths. What this means is that the object is capable of capturing microwave radiation sent its way, and then trap it on the inside in an endless loop.
By definition, a black hole is the collapsed core of a massive star, which is so small and dense compared to the original fireball that it exerts massive gravitational pull on matter around it. The reason why we can't see black holes is because they tend to attract photons in all portions of the electromagnetic spectrum, from radio to X-rays and gamma-rays. If no light is reflected from them, then they appear as empty, black areas in space. However, the radiation does exist within the object, just invisible to our instruments. The same was accomplished with the Chinese-designed instrument, which captures and hides microwaves, in essence acting as a black hole for the microwave wavelength range.
In order to construct the new structure, the team behind the investigation used metamaterials, which are materials with amazing capabilities, such as influencing light and other electromagnetic radiation. Readers may be more familiar with them as the stuff prototype invisibility cloaks are made out of. The new science tool contains 60 concentric rings of metamaterials within, whose combined action contribute to manipulating the microwaves in a manner that ensures they remain forever contained in the black hole. Details of the new work appear in the June 3 issue of the esteemed New Journal of Physics, a publication of the Institute of Physics (IoP) and German Physical Society.
“Since the lossy core can transfer electromagnetic energies into heat energies, we expect that the proposed device could find important applications in thermal emitting and electromagnetic-wave harvesting,” the authors of the new study explain. The accomplishment was made at the Southeast University in Nanjing, China, by a team of physicists led by experts Qiang Cheng and Tie Jun Cui. Both scientists are based at the university's State Key Laboratory of Millimeter Waves.