  The thought experiment (called the clock paradox or the twin paradox)proposed
by Langevin in 1911 of two observers, one staying on Earth and the other making
a trip toward a star with a velocity near the light velocity is very well known
for its surprising result. When the traveler comes back, he is younger that the
stay on Earth. This astonishing situation deduced from the theory of Special
relativity sparked a huge amount of articles, discussions and controversies
such it remains a particular phenomenon probably unique in Physics. We propose
to study it. First we looked for the simplest solutions when one can observe
that the published solutions correspond in fact to two different versions of
the experiment. It appears that the complete and simple solution of Moller is
neglected for complicated methods with dubious validity. We propose to
interpret this avalanche of works by the difficulty to accept the conclusions
of the Special Relativity, in particular the difference in times indicated by
two clocks, one immobile and the second moving and finally stopping. We also
suggest that the name "twin paradox" is maybe related to some subconscious idea
concerning conflict between twins as it can be found in the Bible and in
several mythologies
