## måndag 29 juli 2019

Two twins C and S, Clever (Salviati) and Stupid (Simplicio), decide to part with mutually agreed speed $v$ equipped with identical cesium clocks and so decide to compare the readings of the two clocks, to test the validity of Einstein’s special theory of relativity SR, by exchanging light signals with the clock frequency. Both twins then record a redshift of frequency of the other clock of size $\frac{1}{1+v}$ (with light speed normalised to 1).

C says that this is just what is to expected from laws of physics and it does not say that the clock of S runs slow; it is only a red-shift effect.

S says that the reduction in frequency,  which he records carefully, shows that the clock of C runs slow compared to that of S, and S becomes convinced that C ages more slowly as evidence of SR, which makes S unhappy.

Who is right then? C or S? Is the reason for S to get unhappy, reasonable?

A symmetrical situtation has turned into an unsymmetrical and this is the true twin paradox. What is your solution?