One area of physics that is hard to wrap your head around is relativity. Basically, relativity breaks down into general and special relativity. General relativity deals with large masses and high energies, and it describes how space-time is warped by these. Special relativity deals with what happens during high velocities. Many odd and counter-intuitive effects happen when speeds get close to the speed of light, or c. The problem is that these types of conditions are quite far outside normal experience, so people don’t have any frame of reference as to what these effects would look like—enter Lightspeed.