Heinrich Bruns


Ernst Heinrich Bruns was a German mathematician and astronomer, who also contributed to the development of the field of theoretical geodesy.

Early life

Heinrich Bruns was born on 4 September 1848 in Berlin to Christian Gerhard Bruns, a landscape painter, and his wife, Caroline Henriette Hasse.

Education and professional appointments

Bruns studied mathematics, astronomy, and physics at the University of Berlin during 1866–1871 under Ernst Kummer and Karl Weierstrass and earned a doctoral degree with a dissertation titled De proprietate quadam functionis potentialis corporum homogeneorum. From 1872 to 1873 he was employed at the Pulkowa Observatory in Russia as a calculator. There he met and married Marie Wilhelmine Schleussner, who also worked as a calculator at the observatory. In 1873 he became an observer at the Observatory of Dorpat in Estonia, where he remained until 1876. During this time he also worked as a lecturer at the University of Dorpat.
In 1876, Bruns was appointed an associate professor of mathematics at the University of Berlin. He also worked at the Prussian Military Academy and the Geodetic Institute of Potsdam. In 1882 he went to Saxony as a full professor of astronomy at the University of Leipzig and director of the Leipzig Observatory. That same year, he was elected a member of the academy of science Leopoldina.

Work

Heinrich Bruns was mainly engaged in developing the theoretical side of "the shape of the Earth". The fields of potential theory and the study of equilibrium shapes owe many key results to him. For the study of astronomical refraction he developed an unusual method of calculating the vertical gradient of air temperature together with his Assistant Felix Hausdorff. However, due to a lack of sufficiently accurate measurement methods this method has not been used in practice.
The 20th century's higher geodesy as practiced by Karl Ledersteger was based on theories developed by Bruns, including "Bruns' polyhedron". This construct was envisioned as a world-spanning net. Satellite geodesy turned this thought experiment into a reality with the development of the GPS.

Publications