Classical physics describes the motions of large things moving at slow speeds. That description of the universe, which physicists used to describe the motion of objects from apples to planets for hundreds of years, does not hold for objects moving very fast. In this class, we will look at how traveling close to the speed of light affects the physical properties of objects. Amazingly, simple quantities such as length, time, and mass change dramatically when an object is traveling a significant fraction of the speed of light.