The Lorentz contraction, also called Length contraction, Fitzgerald contraction or Lorenz-Fitzgerald contraction, is the phenomenon that a moving object becomes shorter than it was when measured in its rest frame. This is because of relativistic effects seen between observers moving toward or away from one another. The size of one object as seen by someone moving toward or away from it it is decreased along their line of movement by an amount mathematically related to their speed and the speed of light.