The face of the Milky Way is expected to be repainted

　　A few days ago, the Bethel project team, with scientists from the Purple Mountain Observatory of the Chinese Academy of Sciences as the main members, found through research that the main structure of the Milky Way not only has smooth and regular spiral arms, but also has "bifurcations" or even "bridges" protruding from the spiral arms. The latest research results were published in Science Advance, a sub-journal of the top international academic journal Science, at 2:00 pm EST on September 28, and will be reported as highlights.
　　In many popular science books, the Milky Way is a spiral galaxy composed of hundreds of billions of stars and countless interstellar materials, composed of a galactic center and two or four spiral arms. The spiral arms are a characteristic structure of spiral galaxies, that shiny ring, from the center deep, around each other to the edge of the galaxy. The bright spots on the spiral arms are the massive star-forming regions. Our solar system is located in the innermost part of a large mass of young stars. This stellar mass is often called the local arm or the Orion arm because of its proximity to the Orion Star Association. It is difficult for us to see the whole picture in the Milky Way. However, as long as the distance between the massive star-forming regions on the spiral arms of the Milky Way can be accurately measured, it is like nailing a nail, and the nails can be brought together to draw the shape of the spiral arms of the Milky Way.
　　"The structure of the Milky Way is actually much more complicated," said Xu Ye, a researcher at the Purple Mountain Observatory of the Chinese Academy of Sciences and a key member of the Bethel project. They found a bulge of the Milky Way’s local arm, which extends like a bridge from the local arm to the centaur arm. It is about 12,000 light-years in length and is the longest bulge in the Milky Way ever discovered.
　　Xu Ye introduced that this would show that the Milky Way is not a spiral galaxy composed only of the magnificent main spiral arm as people previously imagined, but more likely a spiral galaxy with rich sub-structures on the main spiral arm. In addition to the "branches" like the main spiral arm, there are also "branches" on the "branches". Based on this research, the appearance of the Milky Way is expected to be repainted.
(Originally published in People’s Daily on September 30, 2016, page 11)