The Corrugated Galaxy The disk of the Milky Way Galaxy disk may actually be rippled. Two ringlike structures of stars wrapping around the Milky Way's outer disk now appear to belong to the disk itself. The results, outlined in a new study, show that the disk is about 60 percent larger than previously thought. Not only do the results extend the size of the Milky Way, they also reveal a rippling pattern, which raises intriguing questions about what sent wavelike fluctuations rippling through the disk. The researchers said the likely culprit was a dwarf galaxy. It might have plunged...