On the 25th anniversary of Ludwig Biermann’s death

Born 13th March 1907 in Hamm, the founding director of the Max Planck Institute for Astrophysics, Ludwig Biermann, died 25 years ago on 12th January 1986 in Munich. Biermann’s scientific career started with his doctoral theses on ”convection zones in the interior of stars“ in Göttingen 1932; stellar structure and evolution in combination with convection were his main topics in the following years. Another important issue was the calculation of atomic data for the interpretation of stellar spectra. Already in 1948, Biermann realised that automatic calculators were needed for the large numerical computations. He brought Heinz Billing to the Max-Planck-Institute for Physics in Göttingen, where the first calculating machine, called G1, was built and went into service in 1952, controlled by punched tape and with 26 memory cells.

Fig. 1: Prof. Ludwig Biermann
Copyright: MPA, Photo courtesy R. Kippenhahn

Fig. 2: Copy of Ludwig Biermann's school-leaving certificate ("Zeugnis der Reife")
Copyright: Gymnasium Hammonense, Hamm

Biermann’s research on the physics of the solar atmosphere in the early 1950s made him realise — together with comet observations — that the Sun emits a steady particle flow. Some ten years later, in October 1962, this theoretical ”solar wind“ could finally be measured by the space craft Mariner 2.

The research on magneto-hydrodynamics and the study of how ionised gases move in interplanetary space led to the founding of two new institutes in the early 1960s: the institute for Plasmaphysics and the Max Planck Institute for Extraterrestrial Physics, respectively. The astrophysics department at the Max-Planck-Institute for Physics itself became an independent part of the institute in 1958 and moved to a new building on the Garching campus in 1980. The free and open work environment, which he created at his institute, continues to pervade life and work there today.

The physics of comets, their origins and appearance in the inner solar system continued to keep Biermann busy even after he officially retired in 1975. His long and productive research career was widely recognised: In addition to many other national and international distinctions, in 1967 he received the Catherine-Wolfe-Bruce gold medal of the Astronomical Society of the Pacific and in 1974 the gold medal of the Royal Astronomical Society London. The German Astronomical Society has named a prize after him and awards the ”Ludwig Biermann Research Prize“ annually to an exceptional young scientist. Each year the Max Planck Institute for Astrophysics invites a world-class scientist to Garching for the Biermann Lectures.

The Gymnasium Hammonense, the school where he received his university qualification in 1925, conceived of a special way to commemorate the 25th anniversary of Biermann’s death. Four 11th grade students prepared a presentation about the astrophysicist in Latin, where they covered also the solar wind (“ventus e sole eiectus”). The following exercise is from Biermann’s final math exam:
An airplane is 3000 m above the Earth. How large is the circle of the surface that an observer in the plane can see, if it is assumed that the Earth is a perfect sphere with Radius r=6377 km and light refraction is neglected?
Would you be able to answer this question without a computer?