Special relativity to a first observer O, and frame S′ (pronounced "S prime") belongs to a second observer O′. Since there is no absolute reference frame in relativity theory, a concept of 'moving' doesn't strictly exist, as everything is always moving with respect to some other reference frame. Instead, any two frames that move at the same speed in the same direction are said to be "comoving". Therefore, "S" and "S"′ are not "comoving". The principle of relativity, which states that physical laws have the same form in each inertial reference frame, dates back to Galileo, and was incorporated into Newtonian physics.
Special relativity (alternative formulations) Special relativity (alternative formulations) As formulated by Albert Einstein in 1905, the theory of special relativity was based on two main postulates: There have been various alternative formulations of special relativity over the years. Some of these formulations are equivalent to the original formulation whereas others result in modifications. "Equivalent to the original ? Yes." According to some references, the theory of special relativity can be derived from a single postulate: the principle of relativity. This claim can be misleading because actually these formulations rely on various unsaid assumptions such as isotropy and homogeneity of space. The question here is