英语科普：银河系可能比之前的估计值大.docxVIP

The Milky1 Way galaxy2 is at least 50 percent larger than is commonly estimated, according to new findings that reveal that the galactic disk is contoured into several concentric ripples4. The research, conducted by an international team led by Rensselaer Polytechnic5 Institute Professor Heidi Jo Newberg, revisits astronomical6 data from the Sloan Digital Sky Survey which, in 2002, established the presence of a bulging7 ring of stars beyond the known plane of the Milky Way. In essence, what we found is that the disk of the Milky Way isnt just a disk of stars in a flat plane -- its corrugated, said Heidi Newberg, professor of physics, applied8 physics, and astronomy in the Rensselaer School of Science. As it radiates outward from the sun, we see at least four ripples in the disk of the Milky Way. While we can only look at part of the galaxy with this data, we assume that this pattern is going to be found throughout the disk.Importantly, the findings show that the features previously9 identified as rings are actually part of the galactic disk, extending the known width of the Milky Way from 100,000 light years across to 150,000 light years, said Yan Xu, a scientist at the National Astronomical Observatories10 of China (which is part of the Chinese Academy of Science in Beijing), former visiting scientist at Rensselaer, and lead author of the paper.Going into the research, astronomers11 had observed that the number of Milky Way stars diminishes rapidly about 50,000 light years from the center of the galaxy, and then a ring of stars appears at about 60,000 light years from the center, said Xu. What we see now is that this apparent ring is actually a ripple3 in the disk. And it may well be that there are more ripples further out which we have not yet seen.The research, funded in part by the National Science Foundation and titled Rings and Radial Waves in the Disk of the Milky Way, was published today in the Astrophysical Journal. Newberg, Xu, and their collaborators used