Milankovich , Milutin

(1879–1958) Yugoslavian mathematician

Milankovich was born at Dalj in Croatia and was educated at the Institute of Technology in Vienna, where he obtained his PhD in 1904. He then moved to the University of Belgrade, remaining there for the rest of his career except for the period 1914–18, during which he was a prisoner of war, but was allowed to pursue his researches in the library of the Hungarian Academy of Science in Budapest.

Milankovich was the most talented of the scientists who worked in the tradition of James Croll in trying to explain the development of the Earth's climate by reference to astronomical events. From 1911 to 1941, when he published his Canon of Insolation and the Ice Age Problem, he tried obsessively, in numerous works, to reconstruct the past climate of the Earth and the planets.

Milankovich realized that the key to past climates was the amount of solar radiation received by the Earth, which varies at different latitudes and depends upon three basic factors. One is the degree of ellipticity of the Earth's orbit, which varies over 100,000 years from being nearly circular to a noticeable ellipticity and which could reduce the amount of insolation by 30%. Secondly, over about 21,000 years a precessional change occurs, which will determine whether the northern or the southern hemisphere receives the most radiation. Finally, the tilt of the Earth's axis to the plane of its orbit changes over about 40,000 years from 21.8° to 24.4°.

Over a period of 30 years Milankovich constructed radiation curves for the last 650,000 years for the summer northern hemisphere from 5°N to 75°N. At first his results looked most impressive for he identified nine climatic minima, which fitted closely the four ice ages identified by Albrecht Penck. However, with the advent of more precise and accurate dating techniques his results are now considered doubtful.