Herman Zanstra

Chemical engineer with an eye for the stars

In 1917, Herman Zanstra graduated cum laude in chemical engineering at Delft University of Technology. He worked in Delft for a few years, but was invited by physicist William Swann as a result of an article. He obtained his doctorate in theoretical physics under Swann at the University of Minnesota in 1923.

Zanstra worked for another year with Swann and subsequently at various places in the Netherlands, Germany and in Niels Bohr’s laboratory in Copenhagen. At Caltech in the United States, he worked as a postdoc. Here, in 1927, he wrote a notorious article
on the application of quantum theory. In it,
he described a method for understanding the luminosity of nebulae and comets, later known as the ‘Zanstra method’. In the years that followed, he worked at various international universities.

After the Second World War, Zanstra returned to the Netherlands and got the job that suited him: he became professor of Astronomy and director of the Astronomical Institute at the University of Amsterdam. In 1959, Zanstra retired at the age of 65. He spent another year as a visiting professor at the University of Michigan.

As the crowning glory of his astrophysical work, Zanstra was invited to address the
Royal Astronomical Society in London in 1961 and received the Gold Medal. He was also awarded an honorary doctorate by the Scottish University of St Andrews in 1965. Zanstra died in 1972, leaving behind more than 60 scientific publications. A moon crater is named after him, as well as planetoid 2945 Zanstra.