Sunday, February 12, 2012

Marcel Gilles Jozef Minnaert

Marcel Gilles Jozef Minnaert was born on February 12, 1893 in Burges, Belgium. His father and mother were school teachers, liberal and supportive of Flemish causes. Minnaert, in his youth was influenced by his uncle, Gerard Minnaert, who was important in the Flemish movement. He grew up in a part of Belgium where Dutch was the common language but all the schools taught in French. After his father's death in 1902 his mother moved the family to Gent, Belgium. Minnaert went to secondary school in Gent and then to the University of Gent, where he studied natural sciences, particularly biology. While a student he was part of a movement to change the language of the university from French to Dutch. He earned his doctorate in biology in 1914.

In 1915-16 he spent a year in Leiden in order to study mathematics and physics. During the German occupation of Belgium he taught physics at the University of Gent, but was forced to flee in 1918, when the Germans left, because he was seen as a collaborator. He relocated to the University of Utrehct, in the Netherlands, where he worked for W.H. Julius who stimulated his interest in solar physics. He finished his second doctorate, this time in astronomy in 1925 the same year that Julius died. Minnaert replaced Julius as the director of the solar spectrograph research project at Utrecht. This was a fascinating time in stellar physics when atomic physics could finally explain what was really happening. Stars, like our sun, are fusing nucleons together, creating new atoms, making the matter that we are made of.

In 1928 he led a successful solar eclipse expedition. In 1940 he published the Utrecht Atlas of the Solar Spectrum and in 1941 he developed the Minnaert function, which is used in the observation of celestial bodies. In 1942, Minnaert, who never hid his liberal political views was taken prisoner by the Germans. He taught physics to his fellow prisoners while he was imprisoned. He was released in 1944. After the war, he returned to the University of Utrecht's observatory and remained director until his retirement in 1963. In addition to his astronomical writings Minnaert also published a physics book that was popular in the Netherlands and was translated, and also a book of poetry dealing with astronomical subjects. Honors won by Minneart include the Bruce medal, presented by the Astronomical Society of the Pacific in 1951 and a gold medal from the Royal Society of London, in 1947. Minneart also has a crater on the moon and an asteroid named after him.

Mineart died on October 26, 1970.


De Jager, C.; "In Memoriam: Marcel Gilles Jozef Minnaert (12 Februarty 1893-26 October 1970)"; Astrophysics and Space Science(1971)10:83-85

Unsold, Albrecht;"In Memorian: Marcel Gilles Jozef Minnaert";Solar Physics(1971)17:3-5

Anon; "Biographies: Marcel Gilles Jozef Minnaert"; online at

Marcel Minnaert Wikipedia Entry

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