Relativity Lite

Gravity Lite | 43 CHAPTER 4 Gravity Lite PUTTIN’ ON A LITTLE WEIGHT The first three chapters have talked about the consequences of the constancy of the speed of light for objects moving at uniform speeds and the observation that physics must be the same in all frames of reference. Einstein extended his theory of the constancy of the speed of light to describe situations in which acceleration was present. He called this his general theory of relativity since it contains zero acceleration (constant speed) as a limit. Consider a spaceship undergoing constant acceleration (increasing speed) to the left in free space (far away from gravitational forces). If a beam of light enters the ship, as in the bottom picture of figure 1a, it will hit the far wall nearer the thrusters than the point on the near wall where it entered because the ship is moving (top picture of figure 1a).