Abstract. Besides Einstein’s two fundamental postulates, additional assumptions are made in various derivations of the Lorentz transformation (LT). Two or three so-called exact derivations of the LT have been highly abstract and abstruse. Thus, the validity of the derivation of the LT has been questioned. Here, we present a rigorous derivation of the LT, the approach of which differs from that typically employed. Our derivation is only based on the constancy of the speed of light and two thought experiments. No additional assumptions are needed because the constancy of the speed of light is used to prove the necessary assumptions.

A rigorous derivation of the Lorentz transformatio