Milutin Milanković
Milutin Milanković was a Serbian mathematician, astronomer, climatologist, geophysicist, civil engineer, university professor, popularizer of science and academic.
Milanković gave two fundamental contributions to global science. The first contribution is the "Canon of the Earth's Insolation", which characterizes the climates of all the planets of the Solar System. The second contribution is the explanation of Earth's long-term climate changes caused by changes in the position of the Earth in comparison to the Sun, now known as Milankovitch cycles. This partly explained the ice ages occurring in the geological past of the Earth, as well as the climate changes on the Earth which can be expected in the future.
He founded planetary climatology by calculating temperatures of the upper layers of the Earth's atmosphere as well as the temperature conditions on planets of the inner Solar System, Mercury, Venus, Mars, and the Moon, as well as the depth of the atmosphere of the outer planets. He demonstrated the interrelatedness of celestial mechanics and the Earth sciences and enabled a consistent transition from celestial mechanics to the Earth sciences and transformation of descriptive sciences into exact ones.
A distinguished professor of applied mathematics and celestial mechanics at the University of Belgrade, Milanković was a director of the Belgrade Observatory, member of the Commission 7 for celestial mechanics of the International Astronomical Union and vice-president of Serbian Academy of Sciences and Arts. Beginning his career as a construction engineer, he retained an interest in construction throughout his life, and worked as a structural engineer and supervisor on a series of reinforced concrete constructions throughout Yugoslavia. He registered multiple patents related to this area.
Life
Early life
Milutin Milanković was born in the village of Dalj, a settlement on the banks of the Danube in what was then part of Austro-Hungarian Empire. Milutin and his twin sister were the oldest of seven children raised in a Serb family. Their father was a merchant, landlord and a local politician who died when Milutin was seven. As a result, Milutin and his siblings were raised by his mother, grandmother, and an uncle. His three brothers died of tuberculosis at a young age. As his health was fickle, Milutin received his elementary education at home, learning from his father Milan, private teachers, and from numerous relatives and friends of the family, some of whom were renowned philosophers, inventors, and poets. He attended secondary school in nearby Osijek, completing it in 1896.In 1896, he moved to Vienna to study Civil Engineering at the TU Wien and graduated in 1902. In his third year of studies, Milanković found more free time for wider education. He paid his full attention to the monumental buildings of Vienna, thereby gradually understanding all the beauty of architecture. He also visited Viennese museums and galleries, after which he became an admirer of Raphael's Madonna del Prato. He showed great interest in the Vienna Opera, which he visited regularly. In addition, he devoted his attention to learning the French language by taking private lessons and attending summer French language course in Geneva in 1899. During a stay in Switzerland, Milankovitch visited the Institute for the Testing Building Materials in the
Polytechnic in Zurich. In the Viennese ″Café Elisabethbrücke″, which was not fashionable but served only for reading, he spent an hour or two daily reading numerous newspapers and magazines. The professor of the science of the building bridges,, the top expert of Viennese Mechanics of that time, taught the most important subject of the fifth school year. In Brikʼs teaching, young Milankovitch found strong inspiration for later scientific work, as he describe it: ″Brikʼs lectures were very interesting to me. His mastering of mathematical analysis was excellent and would constantly apply it in his lectures. To a good mathematician it gives certain independence and freedom in solving problems.″
After graduating and spending his obligatory year in military service, Milankovitch borrowed money from an uncle to pay for additional schooling at TU Wien in engineering. At age twenty-five, his PhD thesis was entitled Contribution to the Theory of Pressure Curves and its implementation allowed assessment of pressure curves' shape and properties when continuous pressure is applied, which is very useful in bridge, cupola and abutment construction. His thesis was successfully defended on 3 December 1904; examination committee members were Johann Emanuel Brik, Josef Finger, Emanuel Czuber and Ludwig von Tetmajer. He then worked for an engineering firm in Vienna, using his knowledge to design structures.
Middle years
Structural engineering
At the beginning of 1905, Milanković took up practical work and joined the firm of Adolf Baron Pittel Betonbau-Unternehmung in Vienna. He built dams, bridges, viaducts, aqueducts, and other structures in reinforced concrete throughout Austria-Hungary. So Milankovitch verified his theoretical knowledge and design tools on numerous reinforced concrete structures that he built during his engineering service in Vienna. Milankovitch participated with structural calculations and practical work in the construction of a total of ten hydroelectric power plants. Among them, the most notable is the one built in Sebeș in the Transylvania region. Milankovitch's specific task was to design a reinforced concrete aqueduct 1200 m long, which would bring water above the turbines of the city's hydroelectric power plant. After that, he was engaged in the construction of the viaduct in Hirschwang in 1906 and in Pitten near Vienna in 1907.He also participated in the construction of bridges in Krainburg, Banhilda and Bad Ischl, then the Belgrade and
Košice sewage system, and Krupp's metal factory in Berndorf. The bridge in Krainburg was particularly beautiful, set on three pillars with four arches each, 30 meters apart. It was built of reinforced concrete, but was later destroyed during World War II.
Milankovitch's great reputation was certainly contributed to by inventions of a new technology of building reinforced concrete ceiling, under the name "System Milankovitch - Kreutz", with which he became famous throughout the Austria-Hungary. He developed and patented the mentioned system of building ceilings with Theodor Kreutz. Compared to the existing ones, this ceiling stood out due to its simpler design, lower consumption of materials and the fact that it had integrated thermal and sound insulation, which made it more aesthetically elegant. The "Milankovitch - Kreutz" construction system was protected by four patents for three inventions.
In 1908, Milankovitch invented and patented new and useful Improvement in the Production of hollow reinforced-concrete slabs AT 42720 B. This patent is the equivalent of Milanovitch's US patent US 940041 A.
In 1905, he published the first paper on armored concrete named Contribution to the theory of reinforced armored pillars. He published the second paper on the same subject based on new results in 1906. In 1908, he published a paper titled "On membranes of same opposition" in which he proves that the ideal shape for a water reservoir of equally thick walls is that of a drop of water. His six patents were officially recognized and his reputation in the profession was enormous, bringing abundant financial wealth.
In 1908, the Austro-Hungarian Empire decided to annex Bosnia and Herzegovina after 30 years of occupation. This was the height of a crisis with the neighboring Kingdom of Serbia, which did not agree with this act. And, there was even a growing danger of war and invasion.
Milanković continued to practice civil engineering in Vienna until 1 October 1909 when he was received an offer University of Belgrade to work as an associate professor at the Department of Applied Mathematics that comprised three basic branches: rational, celestial mechanics, and theoretical physics. Though he continued to pursue his investigations of various problems pertaining to the application of reinforced concrete, he decided to concentrate on fundamental research.
Although this was the turning point in Milankovitch's career, he still does not abandon his "passion for the entire range of construction work, from theoretical ideas to craftsmanship", and continues to engage in design and construction, in parallel with his scientific work. Thus, after arriving in the Kingdom of Serbia, Milanković accepted the design and construction of the first reinforced concrete bridges on the Niš - Knjaževac railway, in the Timok Valley through the Nisevac Gorg, at the request of his friend and collegemate from TU Wien and civil engineer Petar Putnik. This undertaking was unique in that, at the suggestion of engineer Putnik, the type construction of a reinforced concrete bridge was applied for the first time in Serbia. The project of the 30-meter-span bridge, which rests on rocky shores, was done by Milanković with the aim of easier and faster construction of the railway on the route of which the construction of 19 bridges was planned. Thanks to this simple approach, the construction of all 19 bridges is solved with one project. That is precisely why Putnik's construction company won this job at the public procurement in 1912, when construction began. Milanković participated in the construction of the first of the nineteen bridges, which was located near Svrljig, where he fully immersed himself in the work and took care of how "the concrete is mixed, distributed over the formwork and compacted". Meanwhile, Milankovitch was granted citizenship of the Kingdom of Serbia in 1910.
Planet's insolation
His first papers were in the field of celestial mechanics, Properties of motion in a specialized three-body problem, On general integrals of the n-body problem, On kinematic symmetry and its application to qualitative solutions of dynamics problem, but from 1912 Milankovitch began to be interested in cosmic climatology or solar climate. He began working on it in 1912, after he had realized that "most of meteorology is nothing but a collection of innumerable empirical findings, mainly numerical data, with traces of physics used to explain some of them... Mathematics was even less applied, nothing more than elementary calculus... Advanced mathematics had no role in that science..."While studying the works of the contemporaneous climatologist Julius von Hann, Milanković noticed a significant issue, which became one of the major objects of his scientific research: a mystery ice age. The idea of possible astronomically-related climate changes was first considered by astronomers and geologists. Milanković studied the works of Joseph Adhemar whose pioneering theory on the astronomical origins of ice ages were formally rejected by his contemporaries and the amateur scientist James Croll, whose work was effectively forgotten after initial acceptance by contemporaries such as Charles Darwin. Despite having valuable data on the distribution of ice on the Alps across various glaciations, climatologists and geologists had not established the root causes of these cycles. Milanković decided to attempt correctly to calculate the magnitude of such influences. Milanković sought the solution of these complex problems in the field of spherical geometry, celestial mechanics, and theoretical physics.
His first work described the present climate on Earth and how the Sun's rays determine the temperature on Earth's surface after passing through the atmosphere. He published the first paper on the subject entitled "Contribution to the mathematical theory of climate" in Belgrade in April 1912. His next paper was entitled "Distribution of the sun radiation on the earth's surface" and was published in June 1913. In December of that year, this paper was read by Wilhelm Wien, and was soon published in the German journal Annalen der Physik. He correctly calculated the intensity of insolation and developed a mathematical theory describing Earth's climate zones. His aim was an integral, mathematically accurate theory which connects thermal regimes of the planets to their movement around the Sun. He wrote: "...such a theory would enable us to go beyond the range of direct observations, not only in space, but also in time... It would allow reconstruction of the Earth's climate, and also its predictions, as well as give us the first reliable data about the climate conditions on other planets."
He published a paper entitled "The problem of the astronomical theory of ice ages" in 1914. Milankovitch married Kristina Topuzović, an amateur opera singer, on 14 June 1914. They decided to go on their honeymoon to Switzerland, but before that they stopped in Milankovitch's native village of Dalj in Austria-Hungary, where they heard that Franz Ferdinand had been assassinated in Sarajevo which was the cause of the July crisis. Meanwhile, the Austro-Hungarian Empire began massing troops in the Balkans near the border with the Kingdom of Serbia in preparation for an invasion. Milankovitch was soon arrested by the Austro-Hungarian authorities because he was a reserve officer in the Royal Serbian Army and at first he spent six weeks under house arrest, but was eventually imprisoned and later sent to a prisoner-of-war camp in Nezsider, Hungary. He described his first day in prison, where he waited to be taken to the Esseg fortress as a prisoner of war, in the following words:
... Sat on the bed, I looked around and started synchronizing with my new social position.... In the suitcase I had my printed works and my notes on the cosmic problem, there was clean paper too and I started writing. It was far past midnight when I stopped. I looked around the room, wondering where I was. It felt like I was in a roadhouse on my trip through the Universe.
His wife went to Vienna to talk to Emanuel Czuber, who was his mentor and a good friend. Through his social connections, Professor Czuber arranged Milanković's release from prison and permission to spend his captivity in Budapest with the right to work. After six months spent in the prison camp, Milanković was released on 24 December 1914.
Immediately after arriving in Budapest, Milanković met the Director of the Library of the Hungarian Academy of Science, Kálmán Szily who, as a mathematician, eagerly accepted Milanković and enabled him to work undisturbed in the Academy's library and the Central Meteorological Institute. Milanković spent four years in Budapest, almost the entire war. His was only restricted not to leave town and to report to police office once a week. In 1915, Milanković's son Vasilije-Vasko was born in Budapest. He used mathematical methods to study the current climate of inner planets of the solar system.
He shared the general opinion at the time that Mars and Venus contained water on their surface. This was logical thinking, since Earth has water, Mars has polar cap, and Venus has white clouds that associate on the water vapor. This significantly influenced his calculations for the basic thermal climate characteristics of these two planets. In 1916 he published a paper entitled "Investigation of the climate of the planet Mars". He knew the size of Mars and its distance from the Sun, but also that it has a similar rotation speed and axis orientation as Earth. Milanković calculated that the average temperature in the lower layers the atmosphere on Mars is and the average surface temperature is. Also, he concluded that: "This large temperature difference between the ground and lower layers of the atmosphere is not unexpected. Great transparency for solar radiation makes that is the climate of Mars very similar to altitudes climate of our Earth." In any case, Milanković's work suggested that Mars has a harsh climate, and calmed mounting enthusiasm concerning the prospect of discovering the presence of liquid water on the surface of Mars. He discussed the possibility of life on Mars and was skeptical that it could have complex life forms as well and vegetation. In addition to considering Mars, he dealt with the climatic conditions prevailing on Venus and Mercury.
According to his own words, Milankovitch did not know the speed of rotation of Venus, the orientation of the axis, as well as the thickness and composition of the atmosphere. He was awere with Schiaparelli's suggestion that Venus has a slow rotation period equal to the duration of its orbits around the Sun, but he was skeptical because he thought that Venus would lose its atmosphere during a long-term day due to the effects of Solar Radiation. At the last, he accepted spectroscopy observations from that time that suggested a shorter rotation period similar to Earth's. So he considered a greenhouse effect on Venus calculated the temperature in the outer limit of the atmosphere , the upper layer, the middle layer and the lower layer of the atmosphere as well as a ground temperature of. In his literary work Through Distant Worlds and Times, he described of Venus in the following words:
Here we are in the temple of Isis and Osiris, more magnificent than Schinkel himself imagined. From its huge dome, covered with a gently mother-of-pearl mosaic, a white mysterious light spills over the interior of this home. That dome, that's the sky of Venus. The Sun is never visible on it, only the Sun's silvery glow. Not a single star twinkles in this sky; no messenger of the universe reaches this sanctuary...What is this? A storm is raging in my head, blood vessels are beating
like sledgehammers, I'm out of breath. You are pale, dear miss, your legs are wobbly - you have completely fainted... Half unconscious, I carry you, in my arms, to our Earth...
He also discussed the possibility of life on Venus. He thought that the mystery of this planet lies in the answer to the question about its axis, the speed of rotation or how long a day lasts on Venus.
His calculations of the surface temperature conditions on the neighboring Moon are particularly significant. Milankovitch knew that the moon rotates on its axis in 27.32 days, so lunar daytime on one side of the moon last about 13.5 Earth days. Milankovitch calculated that the temperature after a long moon night, in the early morning on the Moon, or before the rise of the Sun over horizon, was. At noon, it rises on, only to reach its maximum value one Earth day later. At sunset, the temperature drops. According to Milankovitch, a sudden cooling occurs during the night.
From 1912 to 1917, he wrote and published seven papers on mathematical theories of climate both on the Earth and on the other planets. He formulated a precise, numerical climatological model with the capacity for reconstruction of the past and prediction of the future, and established the astronomical theory of climate as a generalized mathematical theory of insolation. When these most important problems of the theory were solved, and a firm foundation for further work built, Milanković finished the manuscript under the title Mathematische Grundlagen der kosmischen Strahlungslehre that he sent to his Professor Czuber in Vienna at the summer of 1917. Czuber contacted a publishing house in Leipzig, but since there was a shortage of paper in early 1918, the printing of the book was cancelled. In the fall of 1917, Milankovitch got a job in a construction bureau in Budapest, where he worked on detailed projects of reinforced concrete constructions of a new six-story tuberculosis sanatorium built in the High Tatras, as well as on other important projects.
After the Great War, the Austro-Hungarian Empire disintegrated and new states such as the Kingdom of Serbs, Croats and Slovenes, Republic of Austria, Kingdom of Hungary and
Czechoslovak Republic were formed on its remains. Milanković returned from Budapest to Belgrade with his family after a three-day trip by steamboat ″Gizella″ on 19 March 1919. He continued his professorial career, becoming a full professor at the University of Belgrade. Milanković then, with the help of Professor Ivan Đaja, prepared the French text of this work and it was published under the title "Théorie mathématique des phénomènes thermiques produits par la radiation solaire" in 1920 in the edition of the Yugoslav Academy of Sciences and Arts from Zagreb and the Gauthier-Villars in Paris. That same year, he was elected a corresponding member of the Serbian Royal Academy of Sciences in Belgrade and the Yugoslav Academy of Science and Arts in Zagreb.