Predicting the existence of the 21 cm hyperfine line of neutral interstellar hydrogen in 1944 established Hendrik C. van de Hulst as a central figure in modern radio astronomy. This theoretical breakthrough allowed him, alongside Jan Oort and Lex Muller, to map neutral hydrogen within the Milky Way, eventually revealing the galaxy’s hidden spiral structure for the first time.
Early Career and Theoretical Research
Born in 1918 in Utrecht, Netherlands, Hendrik Christoffel van de Hulst pursued his academic studies at Utrecht University. His early work focused on the physics of light scattering by spherical particles. This research formed the basis of his doctoral thesis and led to the formulation of the anomalous diffraction theory. His 1957 book, Light Scattering by Small Particles, remains a significant contribution to the field of electromagnetic scattering.
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Van de Hulst spent the vast majority of his professional life at Leiden University. Joining the faculty in 1948, he maintained a continuous tenure there through 1984, excluding a brief period between 1952 and 1955. Throughout his career, he authored extensive research covering topics such as the solar corona and interstellar clouds. In 1980, he published his second major work, Multiple Light Scattering.
International Leadership
Beyond his academic appointments, Van de Hulst transitioned into a leadership role for international space research initiatives starting in 1960. His career was marked by numerous professional affiliations, including membership in the Royal Netherlands Academy of Arts and Sciences, the United States National Academy of Sciences, the American Academy of Arts and Sciences, the American Philosophical Society, and the Royal Society as a Foreign Member.
Recognition and Legacy
His scientific contributions were acknowledged through several prestigious international honors. He received the Henry Draper Medal and the Eddington Medal in 1955, followed by the Rumford Medal in 1964. Later in his life, he was awarded the Akademiepenning in 1983, the Janssen Medal in 1992, and the Karl Schwarzschild Medal in 1995. He held the Karl G. Jansky Lectureship in 1987. Van de Hulst died in 2000 in Leiden, leaving behind a legacy that includes the naming of asteroid 2413 van de Hulst.
Fast facts
- Born: 1918, Utrecht
- Died: 2000, Leiden
- Education: Utrecht University
- Primary Employer: Leiden University
- Key Publication: Light Scattering by Small Particles (1957)
- Foreign Member of the Royal Society: 1991
- Eponymous Asteroid: 2413 van de Hulst
Questions readers ask
What is the van de Hulst approximation?
It is a scientific method for calculating light scattering by small particles, formulated as part of his research into anomalous diffraction.
What was his primary discovery regarding the Milky Way?
He predicted the 21 cm hyperfine line of neutral hydrogen, which enabled researchers to map the spiral structure of the galaxy.
Achievements
- Rumford Medal — 1964
- Foreign Member of the Royal Society — 1991
- Bruce Medal — 1978
- Held posts at Leiden University
- Educated at Utrecht University
