No, CERN hasn’t started slamming protons into each other at the Large Hadron Collider early. And no, a top secret warp drive hasn’t been test-driven in Earth orbit (not that we know of anyway). In reality, an electromagnetic black hole has been fabricated in the laboratory for the first time.
Before you start getting concerned that the planet will soon be swallowed up by a rampaging singularity, the black hole in question isn’t the gravitational behemoth you might find after a supernova or in the center of the Milky Way. This particular table-top black hole mimics the curvature of space-time, creating a fabricated event horizon that swallows electromagnetic radiation at microwave wavelengths.
The best thing is that this experiment isn’t just for curiosity-sake, it has a practical application that could revolutionize future solar panel design, making the production of solar energy a lot more efficient than it is currently.
According to previous theoretical studies, mimicking the curvature of space-time around an analog black hole should be possible, guiding electromagnetic radiation around a cylindrical structure “consisting of a central core surrounded by a shell of concentric rings” (as explained by the New Scientist article). The theory is that a material of increasing permittivity (a characteristic of the medium electromagnetic radiation travels through, influencing the electrical component of the photons) could be used between the outer and inner surface of the cylinder. If the transition is smooth enough, and the permittivity eventually matches that of the cylinder core, the photons should be absorbed by the core, rather than reflected.
Although the physics sounds complicated (and I think I’d have to see the apparatus up-close to fully appreciate what is going on), the result is astonishing. What’s more, theory has just been turned into a working model by Tie Jun Cui and Qiang Cheng at the Southeast University in Nanjing, China. This is the world’s first working black hole.
By designing a printed circuit board with an intricate pattern of “meta-materials” (i.e. a man-made material that can alter the characteristics of the passage of electromagnetic radiation), a steady permittivity gradient was created, ensuring the photons’ absorption by the core. The physicists used microwaves, not optical light, in this set-up as the wavelength of microwaves is easier to manage (the wavelength of microwaves in the electromagnetic spectrum is longer than optical light, so larger scale meta-material patterns could be made).
“When the incident electromagnetic wave hits the device, the wave will be trapped and guided in the shell region towards the core of the black hole, and will then be absorbed by the core,” says Cui. “The wave will not come out from the black hole.”
However, the microwave energy has to go somewhere (this black hole is still bound by physical laws), and in Cui and Cheng’s black hole, microwave energy is converted into heat.
This sounds like fun, but how can this technique be used in solar panels? Although optical light can’t be manipulated so easily, Cui is confident that by the end of this year that he will be able to manufacture an optical black hole. If this can be done, then it isn’t such a stretch of the imagination to think that a meta-material surface could replace traditional photovoltaic cells to literally suck sunlight into an array of tiny black holes printed in a circuit board.
Image: The experimental results of the black hole when the microwave beam is pointed at different angles from the central core (or “event horizon”). Credit: Qiang Cheng and Tie Jun Cui.