Right now, the Andromeda Galaxy is speeding toward us at 110 km/s (68 miles per second). In about 4.5 billion years, it will collide with the Milky Way, reshaping both galaxies. But don’t expect an explosion—since galaxies are mostly empty space, stars will pass by each other without many direct collisions. Instead, gravity will stretch and twist them into new shapes, eventually forming one giant galaxy: Milkomeda.