Spectrum drive is the primary method of space travel for humans traveling between star systems. The drive works by taking the space craft out of the electromagnetic spectrum which limits their speed to slower than light travel, and places them in the "brane," a dimension of gravity wells so powerful they pull objects at enormous speeds. A craft in the brane which latches onto one of these gravity wells can re-enter regular space and find itself many light years from where it had previously been in a matter of days, or sometimes even hours. Travel in the brane can be dangerous, however, as one must remain focused on his or her gravity source, and not be pulled away by other gravity wells. They must also be certain to re-enter regular space in the open, and not directly into a star, a planet, or some other object in space.