On October 8, Beijing time, new scientists reported that a plastic black hole can also surround light like a real black hole. Whether it is an artificial or natural black hole, scientists can observe its structure in real time. Unlike a real black hole, it is not dangerous. It can help uncover the strangest things in nature to obtain accurate data; One of the celestial bodies may even be of enlightening significance to devices that obtain energy, such as solar cells
black holes are famous for swallowing passing light and any object, but they can only devour objects after quietly waiting for them to pass through a point called horizon. In contrast, little is known about the photon layer of a black hole, which is a curved space-time region outside the event horizon, and it will only surround the light on the curved path. Astronomers have never observed the photon layer, even outside a real black hole, because it is clear that the trapped light cannot escape and reach your eyes, so you cannot see it
in order to visualize this process, scientists at Nanjing University in China created an artificial black hole. In the natural environment, black holes will devour and trap light through their strong gravity, so it is not only very difficult but also extremely dangerous to recreate this process in the laboratory environment. On the contrary, Liu's research team objectively evaluated the application range of extruded plates, using plastic sheets to simulate the gravitational effect through different refractive indexes. The refractive index determines how much light can be bent by matter
with the improvement of living standards, light curves are made
the refractive index varies with different substances, which is why the straw placed in the water cup looks bent: water refracts light more than air, so it has a larger refractive index. Materials with a constantly changing refractive index will behave more extreme, and a large number of small bends will create a smooth curve rather than a photon layer of a black hole
Liu's team also added quantum dots to melt acrylic glass. The former is a small piece of material with semiconductor properties, which will fluoresce when illuminated. The mixture is then poured onto a rotating quartz sheet and spread out slowly
the research team placed a microscopically visible polystyrene ball in the center as an anchor. The closer the mixture material is to the polystyrene ball, the thicker it is, and the farther it is from the polystyrene ball, the thinner it is. This produces the same effective refractive index as the space curvature around the black hole, Liu said. In fact, the Einstein field equation used to model black holes may also be used to describe the behavior of light in acrylic acid in practice
emitting lasers to irradiate materials will enable scientists to observe active man-made black holes and visualize other familiar gravitational effects. The beam far away from the microsphere will produce a slight bending, and gravity will produce the same effect in space, which is called gravitational lensing effect. This effect occurs when a beam of light passes through a huge celestial body, such as a star or galaxy. This effect will cause the path of the beam to change when it passes through the curved space-time, which will be conducive to better observation of distant celestial bodies, such as exoplanets
however, in an artificial black hole, this gravity will gradually increase as the laser gradually approaches the polystyrene ball, and finally reach a critical point, that is, 180 degrees of completely distorted light. Scientists have previously created artificial black holes to simulate the event horizon of black holes, trying to detect the mysterious process called Hawking radiation, but this is the first man-made object to reconstruct the photon layer
visible sphere
in addition, unlike real black holes, photon layers will become visible through quantum dots. Although the actual light trapped is still invisible, as is the case in a real black hole, quantum dots can absorb some of the light and release red light from different angles, making it able to escape the gravity of the black hole. This provides accurate tracking of the path of the real photon layer and can be imaged by the camera
our research provides a simple but original method to simulate the light siege near a black hole. Liu said. ULF Leonhardt of the Weizmann Institute in rehowart, Israel, believes that Liu's structure provides another way to study black holes. Leonhardt previously created an artificial horizon. It shows that the lens effect described in general relativity is not mysterious. You can use everyday materials to produce the same effect
Liu said that this model can be used to study the general relativity effect near real black holes, but the ability to encircle light will have more practical applications. It can be used in solar cells, photon detectors, micro lasers and other energy harvesting devices