Paul Gruner

Life

He attended high school in Morges, the free Gymnasium Bern, and passed the Matura at the Municipal Gymnasium in Bern. He then studied at the Universities of Bern, Strasbourg, and Zurich. He received his doctorate in 1893 with Heinrich Friedrich Weber in Zurich. Thereafter (1893-1903), he taught physics and mathematics at the free Gymnasium Bern. In 1894 he completed his habilitation in physics and was a lecturer from 1904 titular professor in Bern. There he was an associate professor from 1906 to 1913, and finally from 1913 to 1939 Professor of Theoretical Physics ( first in Switzerland). From 1921 to 1922 he was rector of this university.

In 1892 he became a member of the Natural History Society in Bern, 1898, he was its secretary from 1904 to 1906 and 1912 to 1914 Vice President and President, from 1939 an honorary member. He was also a member of the Swiss Society of Natural Sciences, the Vice President, he was from 1917 to 1922. He also was a member of the Swiss Physical Society, the Vice President, he was from 1916 to 1918 and President from 1919 to 1920. He participated in the foundation of physics Helvetica Physica Acta magazine, standing in front of the Swiss Meteorological Commission as president, and in connection with his Christian worldview and his rejection of materialism, he was a member of the Kepler Federal.

Scientific work

He has written scientific and popular scientific papers on a range of topics. Particularly well known were his work on the optics of turbid media and twilight phenomena, but he also published in the fields of relativity theory and its graphical representation by means of special Minkowski diagrams, radioactivity, electron theory, kinetic theory of gases, thermodynamics, quantum physics.

Albert Einstein in 1903, introduced by a colleague at the patent office in Bern, Josef Sauter in the Naturalist Society in Bern, where he met with Sauter's friend Paul Gruner, then a lecturer in theoretical physics, met. Einstein held some lectures in the house Gruner and corresponded with him from now on. Einstein sought in 1907 to the habilitation as Privatdozent, and was designed by Gruner, now an associate professor in Bern, supported. 1908 Einstein finally became a Privatdozent in Berne.

Minkowski diagram

Developed from May 1921 Gruner and Josef Sauter symmetric Minkowski diagrams. In works from 1922 to 1924, he expanded his analysis. (See Symmetrical Minkowski diagram for mathematical details).

In 1922, he explained that the construction of such diagrams allows the introduction of a third reference system with orthogonal space - and time -axis as in ordinary Minkowski diagrams. Consequently, it is possible that the coordinates of the other two, and inertial systems can be projected onto this axis, thereby forming a so-called " universal reference system " with " universal coordinates" may be created for each of a pair of system. Gruner explained that not contradict the theory of relativity, since those coordinates are only valid for one system pair. He added that he was not the first who used universal coordinates, and pointed to two precursors:

Edouard Guillaume analyzed 1918 two inertial frames, and claimed to have found a universal time for the purposes of the Galilean -Newtonian mechanics, which he interpreted as contrary to the theory of relativity. For details on discussions with the relativity critic Guillaume, see Genovesi ( 2000).

Guillaume's error was detected by Dmitry Mirimanoff ( March 1921 ), who showed that there is no contradiction with the theory of relativity is present. Guillaume Universal Time is in fact established by applying a constant factor from the time of " resources system " between two inertial frames. Means system according Mirimanoff defined in that are moved from the perspective of two Inertialysteme the same speed in opposite directions. Consequently, these "universal" time is only in reference to a single pair system, because it depends on the particular relative speed of the two systems under consideration. Thus it has no further physical meaning. Also Gruner came to the same conclusion as Mirimanoff and praised him for the correct interpretation of this " universal systems ". Gruner also paid tribute to Guillaume as the first of certain mathematical relationships has collected, but he criticized him for the faulty interpretation and related to the misguided criticism of the SRT.

Publications

• Gruner, Paul: Astronomical lectures. Nydegger Baumgart. , Bern 1898.
• Gruner, Paul: Short Textbook of radioactivity .. A. Francke, Bern 1911.
• Gruner, Paul: Elements of the theory of relativity. P. Haupt, Bern 1922.
• Gruner, Paul; Kleinert, Heinrich: twilight effects. H. Grand, Hamburg 1927.
• Gruner, Paul: man's ways and God's ways in the student life. Personal memories from the christl. Student movement. BEG -Verlag, Bern, 1942.