Ernst Heinrich Bruns (4 September 1848 – 23 September 1919) was a German
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...
and
astronomer
An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...
, who also contributed to the development of the field of theoretical
geodesy
Geodesy or geodetics is the science of measuring and representing the Figure of the Earth, geometry, Gravity of Earth, gravity, and Earth's rotation, spatial orientation of the Earth in Relative change, temporally varying Three-dimensional spac ...
.
Early life
Heinrich Bruns was born on 4 September 1848 in
Berlin
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...
to Christian Gerhard Bruns, a
landscape painter
Landscape painting, also known as landscape art, is the depiction in painting of natural scenery such as mountains, valleys, rivers, trees, and forests, especially where the main subject is a wide view—with its elements arranged into a cohe ...
, and his wife, Caroline Henriette Hasse.
Education and professional appointments
Bruns studied
mathematics
Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...
,
astronomy
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...
, and
physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
at the
University of Berlin
The Humboldt University of Berlin (, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany.
The university was established by Frederick William III on the initiative of Wilhelm von Humbol ...
during 1866–1871 under
Ernst Kummer
Ernst Eduard Kummer (29 January 1810 – 14 May 1893) was a German mathematician. Skilled in applied mathematics, Kummer trained German army officers in ballistics; afterwards, he taught for 10 years in a '' gymnasium'', the German equivalent of h ...
and
Karl Weierstrass
Karl Theodor Wilhelm Weierstrass (; ; 31 October 1815 – 19 February 1897) was a German mathematician often cited as the " father of modern analysis". Despite leaving university without a degree, he studied mathematics and trained as a school t ...
and earned a doctoral degree with a dissertation titled ''De proprietate quadam functionis potentialis corporum homogeneorum'' ("On the properties of a certain potential function of homogeneous bodies"). From 1872 to 1873 he was employed at the
Pulkowa Observatory in
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
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 (now
Tartu
Tartu is the second largest city in Estonia after Tallinn. Tartu has a population of 97,759 (as of 2024). It is southeast of Tallinn and 245 kilometres (152 miles) northeast of Riga, Latvia. Tartu lies on the Emajõgi river, which connects the ...
) in
Estonia
Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...
, where he remained until 1876. During this time he also worked as a lecturer at the
University of Dorpat
The University of Tartu (UT; ; ) is a public research university located in the city of Tartu, Estonia. It is the national university of Estonia. It is also the largest and oldest university in the country. .
In 1876, Bruns was appointed an associate professor of mathematics at the University of Berlin. He also worked at the
Prussian Military Academy
The Prussian Staff College, also Prussian War College () was the highest military facility of the Kingdom of Prussia to educate, train, and develop general staff officers.
Location
It originated with the ''Akademie für junge Offiziere der I ...
and the
Geodetic Institute of Potsdam. In 1882 he went to
Saxony
Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...
as a full professor of astronomy at the
University of Leipzig
Leipzig University (), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December 1409 by Frederick I, Electo ...
and director of the
Leipzig
Leipzig (, ; ; Upper Saxon: ; ) is the most populous city in the States of Germany, German state of Saxony. The city has a population of 628,718 inhabitants as of 2023. It is the List of cities in Germany by population, eighth-largest city in Ge ...
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
In geodesy, the figure of the Earth is the size and shape used to model planet Earth. The kind of figure depends on application, including the precision needed for the model. A spherical Earth is a well-known historical approximation that is s ...
" (the title of one of his major works). The fields of
potential theory
In mathematics and mathematical physics, potential theory is the study of harmonic functions.
The term "potential theory" was coined in 19th-century physics when it was realized that the two fundamental forces of nature known at the time, namely g ...
and the study of
equilibrium shapes owe many key results to him, including ''
Bruns formula''.
For the study of
astronomical refraction
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of light ...
he developed an unusual method of calculating the
vertical gradient of
air temperature
Atmospheric temperature is a measure of temperature at different levels of the Earth's atmosphere. It is governed by many factors, including incoming solar radiation, humidity, and altitude. The abbreviation MAAT is often used for Mean Annual Air ...
together with his
assistant
Assistant may refer to:
* Assistant (by Speaktoit), a virtual assistant app for smartphones
* Assistant (software), a software tool to assist in computer configuration
* Google Assistant, a virtual assistant by Google
* ''The Assistant'' (TV seri ...
Felix Hausdorff
Felix Hausdorff ( , ; November 8, 1868 – January 26, 1942) was a German mathematician, pseudonym Paul Mongré (''à mogré' (Fr.) = "according to my taste"), who is considered to be one of the founders of modern topology and who contributed sig ...
. However, due to a lack of sufficiently accurate measurement methods this method has not been used in practice.
The 20th century's higher geodesy (a sub-field of geodesy concerned with measuring the earth on a global scale) as practiced by
Karl Ledersteger
Karl Ledersteger (11 November 1900, in Vienna – 24 September 1972, near Vienna) was an important geodesist and geophysicist.
After studies of astronomy, mathematics and geodesy he worked in Germany and later in the National Survey of Austria. ...
was based on theories developed by Bruns, including "Bruns' polyhedron". This construct was envisioned as a world-spanning net.
Satellite geodesy
Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques ...
turned this thought experiment into a reality with the development of the
GPS
The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geol ...
.
Publications
* ''Über die Perioden der elliptischen Integrale erster und zweiter Ordnung'' (On the periods of
elliptic integrals
In integral calculus, an elliptic integral is one of a number of related functions defined as the value of certain integrals, which were first studied by Giulio Fagnano and Leonhard Euler (). Their name originates from their originally arising in ...
of first and second order). (Dorpat 1875)
* ''Die Figur der Erde'' (The shape of the Earth). (Berlin 1878)
* ''Über eine Aufgabe der Ausgleichsrechnung'' (On a problem of
curve fitting
Curve fitting is the process of constructing a curve, or mathematical function, that has the best fit to a series of data points, possibly subject to constraints. Curve fitting can involve either interpolation, where an exact fit to the data is ...
). (Leipzig 1886)
* ''Über die Integrale des Vielkörperproblems'' (On the integrals of the
many-body problem
The many-body problem is a general name for a vast category of physical problems pertaining to the properties of microscopic systems made of many interacting particles. Terminology
''Microscopic'' here implies that quantum mechanics has to be ...
). (Leipzig 1887)
* ''Das Eikonal'' (The
Eikonal). (Leipzig 1895)
References
*
* Karl Ledersteger, Volume V (J.E.K.) ''Astronomische und Physikalische Geodäsie'' (Astronomical and Physical Geodesy), p. 871. ''Themen der Erdfigur ''(Topics about the earth's shape), Verlag J.B.Metzler, Stuttgart 1969.
* Felix Hausdorff, ''Gesammelte Werke, Band V (Astronomie & Optik)'' (Collected Works, Volume V (Astronomy & Optics)), pp. 135–399, 544–735, Springer-Verlag, Berlin 2006.
Biography of Heinrich Bruns
External links
*
in the catalog of the
German National Library
The German National Library (DNB; ) is the central archival library and national bibliographic centre for the Federal Republic of Germany. It is one of the largest libraries in the world. Its task is to collect, permanently archive, comprehens ...
Heinrich Bruns in Saxon biographyHeinrich Brunsin the catalog of professors at the University of Leipzig
at the University of Leipzig (summer term 1882 to summer term 1914)
Publications by H. Brunsat the
Astrophysics Data System
The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers on astronomy and physics, operated for NASA by the Smithsonian Astrophysical Observatory. ADS maintains three bibliographic collections containing over 15 ...
* F. Hayn
''Anzeige des Todes von H. Bruns.''Astronomische Nachrichten, Vol. 210 (1919), p. 15. (Obituary)
{{DEFAULTSORT:Bruns, Heinrich
1848 births
1919 deaths
19th-century German mathematicians
Scientists from Berlin
19th-century German astronomers
Humboldt University of Berlin alumni
Academic staff of Leipzig University
Academic staff of the Humboldt University of Berlin
20th-century German mathematicians
German geodesists
20th-century German astronomers
Mathematicians from the Kingdom of Prussia
Mathematicians from the German Empire