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Jan Hendrik Oort: star of Dutch radio astronomy

The success of Dutch radio astronomy in the last century was largely due to Leiden astronomer Jan Hendrik Oort. He made astute use of circumstances in the post-war period. Historian Astrid Elbers' research focuses on this golden period.

Mapping the Milky Way

Jan Willem Oort.
Jan Hendrik Oort.

Dutch astronomers were studying the structure of the Milky Way as early as the start of the twentieth century. They wanted to draw up a detailed map of the galaxy. However, traditional telescopes were not up to the task because much of the light from space is obstructed by interstellar dust. But at the end of 1940 Leiden astronomer Jan Hendrik Oort (1900-1992) read an article about radio waves that explained that these are not obstructed by dust and clouds. Oort realised straight away that these radio waves could help Dutch astronomers achieve their ambition.

Remarkable success

Elbers describes in her dissertation (published in 2015) the causes of the rapid and remarkable success of Dutch radio astronomy in the period from 1940 to 1970. A crucial factor was that Dutch radio astronomers had been trained in astronomy, while in other countries it was mainly engineers and physicists who were involved in this field. The Dutch researchers were therefore taken much more seriously. They simply lacked technical knowledge, so they entered into alliances with companies such as Philips, the PTT and the KNMI.

Political qualities

Astrid Elbers, alfa op bètapad.
Astrid Elbers, alfa op bètapad.

These alliances were to prove very useful. The PTT hoped that the new knowledge would lead to innovations in telecommunications, and the KNMI expected more insights into the weather. Although Oort was not involved with these areas of research, he made astute use of their motivations to gain considerable benefits in financial terms. Moreover, during the war he had built up a very useful network on which he was later able to exercise his political talents.

Short lines

Elbers demonstrates in her research the short lines of communication in the Netherlands shortly after the Second World War. The lines between Oort and influential individuals were therefore also very short; not only between him and politicians, but also with the ZWO, the Dutch national financing body for scientific research (the forerunner of NWO). In the mid-fifties, radio astronomers received as much as ten per cent of the total annual budget for scientific research. 

Melkwegstructuur op basis van radiogolven
The Milky Way structure based on radio waves


This was closely linked to post-war politics in the Netherlands. Science, and particularly 'pure science', was regarded as a crucial element in post-war reconstruction. The expectation was that pure scientific research would lead to innovations and applications that could stimulate the economy. Oort made good use of this viewpoint. 

(Coen van Beelen)

PhD defence

Astrid Elbers –  Early Dutch Radio Astronomy (1940-1970). The People and the Politics. PhD defence on 10 December 2015.

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