Some scientist, such as the famous Stephan Hawkings, has described our universe as an apple, bent. To get from one side of the universe is a straight line correct? To get from New York to Houston is a straight line in a plane right? It's not! The universe is curved just like the suface of the earth. To go straight to Hong Kong from Mexico City is to dig through the center of the earth. So, to get to other side of the universe faster is to go through the center of the universe, technically.

How do we know the universe is a sphere and not a flat plane? Actually we don't exactly, but we have enough evidence to confirm it. One is the way the universe is expanding. (Not getting into any detail on to the expansion on the universe right now, that comes in later features.) But imagine the universe is a sphere, to get to the other side of the galaxy would mean traveling at an arch instead so a straight line. However, to travel in the stragiht line you have to rid the vessel of the forces that effect the universe into being bent. Stars create dents with their gravity in the universe, thus creating massive rifts or valleys in the surface of the universe. Well the idea is to use these valleys in space and time to our use.

Since something with great mass causes the rift, maybe we need to find something with greater mass but does not affect things in the way normal matter does. Possibly we could find this in dark matter but who knows?