The calculations concerning coordinates of space and time presented so far are not sufficient for the
complete understanding of the relativistic transformation procedure. Already in the year 1900 the essential
additional principle of “local time” and the consequences connected with it were investigated by H. Poincaré.
Later A. Einstein implemented the general statement, that the local time of moving observers must always be
connected by synchronization processes.
Inside Special Relativity the synchronization of incidents between moved observers is of paramount importance.
It is part of any comprehensive lecture concerning Special Relativity, further a multitude of publications exists
of which only a small part can be discussed here.
Generally the issue can be split in two categories:
The synchronization of incidents by exchanging signals,
The synchronization of incidents by the exchange of clocks.
The conclusions are not in conformance with the intuitive human understanding of simultaneity and are therefore
not easy to understand. This is due to the fact, that the exchange of signals between two observers is always
carried out with a velocity equal to the speed of light and that this fact has to be included into the considerations.
In the following the synchronization of incidents using the exchange of signals is investigated first,
the synchronization using the exchange of clocks will be evaluated in chapter 5.