Alfred Heinrich Bucherer (* 9 July 1863 inCologne; † 16 April 1927 inBonn) was a Germanphysicist, who is known for his experiments onrelativistic mass. He also was the first who used the phrase "theory of relativity" for Einstein's theory ofspecial relativity.
He studied from 1884 until 1899 at theUniversity of Hannover, theJohns Hopkins University, theUniversity of Strassburg, theUniversity of Leipzig, and theUniversity of Bonn. In Bonn hehabilitated in 1899 and taught there until 1923.[1]
In 1903 Bucherer published the first German-language book to be completely based onvector calculus.[2]
LikeHenri Poincaré (1895, 1900), Bucherer (1903b) believed in the validity of thePrinciple of relativity, i.e. that all descriptions of electrodynamic effects should only contain the relative motion of bodies, not of the aether. However, he went a step further and even assumed the physical non-existence of the aether. Based on those ideas he developed a theory in 1906, which also included the assumption that the geometry of space isriemannian. But the theory was vaguely formulated and in 1908Walther Ritz showed that Bucherer's theory leads to wrong conclusions with respect to electrodynamics. And contrary toAlbert Einstein, he didn't connect his rejection of the aether with the relativity of space and time.[3]
In 1904 he developed a theory ofelectrons in which the electrons contract in the line of motion and expand perpendicular to it. Independently of himPaul Langevin developed a very similar model in 1905. The Bucherer-Langevin model was an alternative to the electron models of:
All three models predicted an increase of the electron mass if their velocities are approaching thespeed of light. The Bucherer-Langevin model was quickly abandoned, so some experimentalists tried to distinguish between Abraham's theory and the Lorentz-Einstein theory by experiment. This was done byWalter Kaufmann (1901–1905) who believed that his experiments confirmed Abraham's theory, and disproved the Lorentz-Einstein theory. But in 1908 Bucherer conducted some experiments as well, and obtained results which seem to confirm the Lorentz-Einstein theory and the principle of relativity. With exceptions likeAdolf Bestelmeyer with whom Bucherer had a polemical dispute, Bucherer's experiments were regarded as decisive. But it was shown in 1938 that all those experiments of Kaufmann, Bucherer, Neumann etc. showed only a qualitative increase in mass, but were too imprecise to distinguish between the different models. This lasted until 1940, when similar experimental equipments were sufficiently accurate to confirm the Lorentz-Einstein formula,[4] seeKaufmann–Bucherer–Neumann experiments andTests of relativistic energy and momentum.
Bucherer (1906) was the first who used — during some critical remarks on Einstein's theory — the expression "Einsteinianrelativity theory / theory of relativity" ("EinsteinscheRelativitätstheorie"). This was based onMax Planck's term "relative theory" for the Lorentz-Einstein theory. And in 1908 Bucherer himself rejected his own version of the relativity principle, and accepted the "Lorentz-Einstein theory".[5]
Later (1923, 1924), Bucherer criticizedgeneral relativity in some papers. However, this criticism was rejected because Bucherer misinterpreted Einstein's equivalence hypothesis.[6]
| International | |
|---|---|
| National | |
| Academics | |
| People | |
| Other | |
