Milutin Milanković (a.k.a. Milankovitch) (May 28, 1879, Dalj near Osijek, (Austria-Hungary) – December 12 1958, Belgrade) was a Serbian geophysicist, best known for his theory of ice ages, relating variations of the Earth's orbit and long-term climate change, now known as Milankovitch cycles.

Milanković attended the Vienna Institute of Technology where he graduated in Civil Engineering in 1902 and earned a doctorate in technical sciences in 1904. Later he worked in then famous firm of Adolf Baron Pittel Betonbau-Unternehmung in Vienna. He built dams, bridges, viaducts, aqueducts and other structures in reinforced concrete throughout the Austria-Hungary of the time. Milanković continued to practice civil engineering in Vienna until the autumn of 1909 when he was offered the chair of applied mathematics (rational mechanics, celestial mechanics, theoretical physics) in Belgrade. The year 1909 marked a turning point in his life. Though he continued to pursue his investigations of various problems pertaining to the application of reinforced concrete, he decided to concentrate on fundamental research.

Turbulent events took place as soon as he had settled down in Belgrade when the Balkan Wars were followed by World War I. When the war broke out in 1914 (he was just married), he was interned by Austro-Hungarian army in Nezsider and later in Budapest, where he was allowed to work in the library of the Hungarian Academy of Sciences. As early as 1912, his interests turned to solar climates and temperatures prevailing on the planets. Throughout his internment in Budapest he devoted his time to the work in this field and, by the end of the war, he had finished a monograph on the problem which was published in 1920, in the editions of the Yugoslav Academy of Sciences and Arts by Gauthiers-Villards in Paris, under the title Théorie mathématique des phénomènes thermiques produits par la radiation solaire (Mathematical theory of thermic phenomena caused by solar radiations).

The results set forth in this work won him a considerable reputation in the scientific world, notably for his curve of insolation at the Earth's surface. This solar curve was not really accepted until 1924 when the great meteorologist and climatologist Wladimir Köppen with his son-in-law Alfred Wegener, introduced the curve in their work, entitled Climates of the geological past. After these first tributes, Milankovic was invited, in 1927, to cooperate in two important publications: the first was a handbook on climatology (Handbuch der Klimatologie) and the second a handbook on geophysics (Guttenberg's Handbuch der Geophysik). For the former, he wrote the introduction Mathematische Klimalehre und astronomische Theorie der Klimaschwankungen (Mathematical science of climate and astronomical theory of the variations of the climate), published in 1930 in German and in 1939 translated into Russian. Here the theory of planetary climate is further developed with special reference to the Earth.

He created Revised Julian Calendar , in use by manu ortodox chuchs, which tends to be more exact and similar to Gragorian Calendar than original Julian Calendar

For the second textbook, Milanković wrote four sections developing and formulating his theory of the secular motion of the Earth's poles and his theory of glacial periods (Milankovitch cycles), which was built on earlier work by James Croll. Milanković was able to advance on Croll's work partly by improved calculations of the earths orbit then recently published by Ludwig Pilgim in 1904. Fully aware that his theory of solar radiation had been successfully completed and that the papers dealing with this theory were dispersed in separate publications, he decided to collect and publish them under a single cover. Thus, in 1941, on the eve of war in his country, the printing of his great work Kanon der Erdbestrahlung und seine Anwendung auf das Eiszeitenproblem (Canon of Insolation of the Earth and Its Application to the Problem of the Ice Ages) was completed, 626 pages in quarto, in Cemian, published in the editions of the Royal Serbian Academy. This work was translated into English under the title Canon of Insolation of the Ice-Age Problem, in 1969 by the Israel Program for Scientific Translations and published for the U.S. Department of commerce and the National Science Foundation, Washington, D.C..

Objections were raised in the 1950s against the Milanković theory of ice ages; these objections came mainly from meteorologists who claimed that the insolation changes due to the changes in the Earth's orbital elements were too small to significantly perturb the climate system. However, in the late 1960s and 1970s, investigation of the deep-sea sediments brought widespread acceptance of Milanković's view, since the periodicity discovered (100,000 years) matched so closely with the longest orbital period — see Ice age for more discussion.

In addition to his scientific work, Milanković always showed great interest in the historical development of science. In addition to a textbook on the history of astronomy, he wrote two books on a popular level: Through Space and Centuries fictionalized the development of astronomy while the other, entitled Through the Realm of Science, dealt with the development of exact sciences.

Milanković also published a three volume autobiography in Serbian, Recollection, Experiences and Vision, which was never translated. For this reason his son, Vasko Milanković, has completed a biography: My father, Milutin Milanković.

Milanković was elected a corresponding member of the Serbian Academy of Sciences and Arts in 1920, a full member in 1924, a corresponding member of the Yugoslav Academy of Sciences and Arts in 1925 and as member of the German Academy of Naturalists "Leopoldine" in Halle; he was also a member of many scientific societies and related organizations, both in Yugoslavia and abroad.

Namings

• Milankovic - a crater on the far side of the Moon
• 1605 Milankovitch - a minor planet.

External links

• Solar Radiation and Milanković
• Milankovitch Cycles and the Shift of the Tropic of Cancer
• Precession and the Milanković Theory
• Facsimile of Milanković's first work
• NASA Earth Observatory article in the "on the shoulders of giants" series