Stars like our sun travel in orbits within galaxies, such as the Milky Way. But about 15 years ago, scientists discovered some huge, hot stars that were going so fast that they were flying right out of our galaxy. Dr. Kelly Holley-Bockelmann, an astronomer at Vanderbilt University, leads a research team that discovered, for the first time, smaller, sun-like stars going fast enough to leave the Milky Way. But unlike the big hyper-velocity stars, which come from the centre of the galaxy and are thought to have been kicked out by black holes, these small stars come from all directions. Researchers are stumped about why they're going so fast.