A runaway star is moving through the galaxy at a far greater speed than any of the other stars around it. In some cases, the star is moving fast enough to escape the Milky Way Galaxy and enter intergalactic space. A runaway may get a "kick" when it passes close to the supermassive black hole at the center of the galaxy, or when a companion star explodes as a supernova. Many runaway stars leave a "wake" as they plow through the gas and dust scattered between the stars.