title: Terrestrial reference frame
text: # Terrestrial reference frame
  
  A terrestrial reference frame (TRF) is the reference frame as one views from Earth, or from the surface of another Earth-like planet. A TRF affects the way humans perceive almost everything from day to day because as they live on the Earth an Earth-based point of view was the only viewpoint from which the rest of the universe could be observed, at least until the space age. One of the most noticeable results of the TRF is how the Sun appears to rise and set in the sky every day, which is actually an effect of the Earth rotating on its axis.
  
  ## Example Effects
  
  * The flight paths of aircraft.
  * The retrograde motions of the planets, e.g. Mars (which is the easiest to see).
  * The apparent rising and setting of the Sun, Moon, planets, and stars.
  