Marcel Minnaert

Who was Marcel Minnaert?

Marcel Gilles Jozef Minnaert was a Dutch astronomer of Belgian origin. He was born in Bruges and died in Utrecht.

He obtained a PhD in biology at Ghent University in 1914. Later he obtained also a PhD in physics from Utrecht University, under the supervision of Leonard Ornstein.

He was a supporter of the Flemish movement during World War I and endorsed the replacement of French by Dutch during the German occupation of Belgium. Because of this, he was forced to flee Belgium after the end of the war.

In 1918, he found a position at Utrecht University in the Netherlands, initially to do photometric research. In Utrecht, he became interested in astronomy, and he became a pioneer of solar research. He specialized in spectroscopy and the study of stellar atmospheres.

Minnaert was also interested in bubbles and musical nature of the sounds made by running water. In 1933 he published a solution for the acoustic resonance frequency of a single bubble in water, the so-called Minnaert resonance.

In 1937, he was appointed director of the stellar observatory Sonnenborgh in Utrecht and full professor in astronomy at the university.