Share with friends and circle of friends with wechat scan QR code < / P > < p > Author: Jin YeYe editor: Xu Huiyun < / P > < p > following the world's first < a target = "_ blank" href=" https://news.163.com/news/search?keyword=%E9%BB%91%E6%B4%9E "> black hole < / a > after the release of photos, black hole ushered in new progress. < p > < p > at 22:00 on March 24, the event horizon of the first black hole photo ever captured by human beings was < a target = "_ blank" href=" https://news.163.com/news/search?keyword=%E6%9C%9B%E8%BF%9C%E9%95%9C "> the telescope < / a > (EHT) cooperation provides a new perspective for revealing the M87 supermassive black hole_ blank" href=" https://news.163.com/news/search?keyword=%E5%81%8F%E6%8C%AF%E5%85%89 "> images under polarized light < / a >. < / P > < p > more than 300 researchers from various organizations and universities around the world participated in the study. The Shanghai Observatory of the Chinese Academy of Sciences took the lead in organizing and coordinating the participation of domestic scholars including eight researchers in the EHT cooperation. < / P > < p > what is the significance of the new development of the new images released today? < / strong > < / P > < p > this is the first time that astronomers have measured the characterization of < a target = "near the edge of a black hole_ blank" href=" https://news.163.com/news/search?keyword=%E7%A3%81%E5%9C%BA "> polarization information of magnetic field < / a > characteristics. This result is of great significance to the interpretation of M87 < a target = "_ blank" href=" https://news.163.com/news/search?keyword=%E6%98%9F%E7%B3%BB "> how the galaxy < / a > propagates the energetic jet from its core is crucial, and it is helpful to infer the model of accretion disk. "We now see the next key evidence to explain the behavior of the magnetic field around the black hole and how the physical processes in this very dense space drive powerful jets far beyond the galaxy itself," said Monika Mo ś cibrodzka, coordinator of the EHT polarization measurement working group and assistant professor at Radboud University in the Netherlands On April 10, 2019, scientists released the first-ever image of a black hole, revealing a bright ring structure and its dark central region, the shadow of the black hole. Since then, the EHT collaboration has conducted an in-depth study of the supermassive black hole data collected in 2017 at the center of M87 galaxy. They found that much of the light around M87 black hole is polarized. < / P > < p > the first black hole image < / P > < p > the so-called polarization (also known as polarization) is an attribute of electromagnetic wave, which means that the electromagnetic wave oscillates along a specific direction in the plane perpendicular to its propagation direction. Light is a kind of electromagnetic wave, which is composed of coupled oscillating electric field and magnetic field, and the oscillating directions of electric field and magnetic field are always perpendicular to each other, so the polarization signal of light carries the electromagnetic field information of light emission position. < / P > < p > when light passes through some filters (such as the lens of polarized sunglasses), or comes out from the magnetized high temperature area, the light will be polarized. Just as polarized sunglasses help us see better by reducing the reflection and glare from bright surfaces, astronomers can sharpen their field of vision by observing the polarization of light coming from the edge of a black hole. Specifically, polarization measurements allow astronomers to map the lines of force that exist at the edge of a black hole. According to Jason Dexter, assistant professor of the University of Colorado at Boulder and coordinator of the EHT working group, "the observation results show that the magnetic field at the edge of the black hole is very strong, and its force is enough to make the hot gas resist the pull of gravity. Only the gas passing through the magnetic field can enter the event horizon by precession < / P > < p > < strong > why is it difficult to draw? < / strong > < / P > < p > the bright jet of energy and matter from the core of M87 extends at least 5000 light-years, which is one of the most mysterious and spectacular features of the galaxy. Most of the material near the edge of the black hole will fall into it. However, there are also some particles around them that escape immediately before being captured and propagate outward in the form of jets. < / P > < p > in order to better understand this process, astronomers have constructed different models about the behavior of matter at the edge of black holes. But they still don't know how jets larger than the galaxy's scale are emitted from the center of the galaxy, which is usually the size of the solar system, or how matter falls into the black hole. This new eht black hole polarization image enables astronomers to successfully explore the physical process of the outer region of the black hole for the first time, where matter may be inhaled or ejected. < / P > < p > researcher Lu Rusen of Shanghai Observatory, a member of EHT, said that it is difficult to take pictures of black hole polarization for three reasons. First, the polarization characteristics are relatively weak. The second reason is that the polarization radiation is different in each small-scale local area, but if there is not enough resolution to detect the polarization radiation in these areas, the observed polarization characteristics will be weakened due to the superposition effect of different areas. < / P > < p > "finally, the light passes through the hot gas around the black hole in the process of emission and away from the black hole. In this process, there is Faraday rotation effect, which means that the polarization direction will rotate in the magnetized medium, which will weaken the polarization characteristics Lu rushen told first finance. < / P > < p > < p > associate researcher Jiang Wu of Shanghai Observatory, a cooperative member of EHT, added to China first finance and Economics: "conventional very long baseline interferometry (VLBI) polarization measurement is very difficult. Because eht has a higher observation frequency than conventional VLBI, obtaining this polarization image is even more challenging." It can also be understood why it took nearly two years for polarization images to appear after the first black hole images. < / P > < p > in order to observe the center of M87 galaxy, this cooperation connects eight telescopes around the world to create a virtual earth size telescope, eht. Eht's resolution is equivalent to the resolution needed to see a credit card on the moon. This allowed the team to directly observe the shadow of the black hole and the halo around it, which the new polarized image clearly shows is magnetized.