 Here's a very interesting galaxy. It is as large as the Milky Way, but it contains only one-two-hundredth the number of stars. Given the object's large size and faint appearance, astronomers are classifying it as a ultra-diffuse galaxy. Note the galaxies behind it and further away. This is literally a see-through galaxy. That dark matter theory has it that galaxies form around dark matter. So researchers were surprised when they discovered this galaxy has hardly any dark matter at all. Measuring the motion of ten giant globular clusters, astronomers found their velocities to be consistent with the estimated mass of the visible matter. There was no need to assume the presence of dark matter. Researchers have competing theories about how this could happen. We still have a lot to learn.