Vladimir Ignatowski

Vladimir Sergeyevitch Ignatowski, or Waldemar Sergius von Ignatowsky and similar names in other publications (* March 8/20, 1875 in Tbilisi, Georgia; † January 30, 1942 in Leningrad), was a Russian physicist. He was rehabilitated in 1955.

Ignatowski wrote some papers on special relativity. In 1910 he was the first to try to derive the Lorentz transformation by group theory only using the relativity principle, and without the postulate of the constancy of the speed of light (1910b, 1911b, 1911c, 1911h). Although he derived the correct transformation, the invariant limiting speed remained undefined. Ignatowski had to resort to length contraction of moving electrostatic fields in order to identify this limiting velocity with the velocity of light in vacuum. While some said that this approach was insufficient and the second postulate is still needed, others continued the attempts to derive special relativity without the light postulate (see Postulates of special relativity). Ignatowski also investigated the status of rigid bodies within special relativity (1910a, 1911a). He concluded that velocities greater than the speed of light are possible, even though he showed that those are not signal velocities and therefore are not in conflict with relativity (1910b, 1911g). He also formulated a relativistic theory of hydrodynamics (1911f).

Ignatowski is also known for his work in the field of optics, whereby he founded the only optical-mechanical facility in the Soviet Union.