# What is the benefit of the relativistic effects (time dilation and length contraction)? [closed]

Can an observer ever experience the relativistic effects, or he just can observe them. For an observer these effects happens only on other objects that he observe, but can he realize if he is subjected to such effect and can he benefit of them or to be in contact with?
A benefit from the relativity THEORY is $E=mc^2$, but what can we benefit from effects that we can only observe but not to interact with?
I am talking here mainly from a mechanical point of view since in electromagnetism the charges can interact from distance and these effects can come into play.

## closed as unclear what you're asking by Kyle Kanos, Sebastian Riese, John Rennie, ACuriousMind♦, user36790 Feb 21 '16 at 18:49

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• Is ageing less rapidly a benefit? – Farcher Feb 20 '16 at 18:31
• @Farcher Hi. May I ask a question: Can we really say that someone will be aging less rapidly without accelerations, that is only by moving with constant relativistic speed? Thank you. – Constantine Black Feb 20 '16 at 18:38
• But only other observer can deduce he is aging less rapidly, to him he is aging the same. There is one benefit in that sense, if he has someone to care about he can send him with the speed of light and to enjoy his youth. – Pekov Feb 20 '16 at 18:40
• For instance, the circulation of the electric field around a charge is not zero for an observer watching the charge moving, but what can he do about it, what's the benefit of that if he cannot interact with the charge? – Pekov Feb 20 '16 at 18:44
• What benefits are you thinking? – Kyle Kanos Feb 20 '16 at 18:45

Using the observed half-life of a muon, in our laboratory frame, we get about $2.2 \mu$s. However, when the muons are created by cosmic ray interactions with the upper atmosphere, creating very high speed particles, we observe that the half-life is much greater.