Contraction of Length


In this section we look at the spacial interval of a clock time tick interval.


The animation depicts a clock and a grid with vertical blue poles.

  • top: stationary relative to the clock with the grid moving at 0.87c.
  • bottom: stationary relative to the grid with the clock moving at 0.87c.

As the clock passes the grid the clock ticks each unit on the clock as a blue pole passes. When the clock is moving and time slows the distance between ticks on the clock is greater than when the clock is stationary.

At the top, with the grid in motion, it must contract so the blue poles pass the clock on each tick of the clock.


  • The Doppler Effect is not depicted in the animation.
  • The aberration of light is not included in the animation.