Muon experiment: The experiment that demonstrates proves the prediction of time dilation by the special relativity. Muons, that are short-lived subatomic particles, are made with enormous energy in the upper environment by the interaction of energetic cosmic rays. The muons have a very short half life in their own reference frame, around 2.2 us. As they are travelling very near to c, though, time dilation effects must become significant. A naive computation would point out that, without special relativistic effects, the muons would travel on the average only around 700 m before decaying, never accomplishing the surface of the Earth. The observations reveal, though, that significant numbers of muons do reach the Earth. The elucidation is that muon is in a moving frame of reference, and therefore time is slowed down for the muons associative to the Earth, efficiently extending the half life of the muons associative to the Earth, permitting some of them to reach the surface.