Hendrik Christoffel "Henk" van de Hulst (19 November 1918 – 31 July 2000) was a Dutch

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

. In 1944, while a student in Utrecht, he predicted the existence of the 21 cm hyperfine line of neutral interstellar

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

. After this line was discovered, he participated, with Jan Oort and Lex Muller, in the effort to use

radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...

to map out the neutral hydrogen in our

galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

, which first revealed its spiral structure. Motivated by the scattering in cosmic dust, Van de Hulst studied light scattering by spherical particles and wrote his doctoral thesis on the topic, subsequently formulating the anomalous diffraction theory. He spent most of his career at

Leiden University Leiden University (abbreviated as ''LEI''; ) is a Public university, public research university in Leiden, Netherlands. Established in 1575 by William the Silent, William, Prince of Orange as a Protestantism, Protestant institution, it holds the d ...

, retiring in 1984. He published widely in astronomy, and dealt with the solar corona, and interstellar clouds. After 1960 he was a leader in international space research projects. In 1956 he became member of the Royal Netherlands Academy of Arts and Sciences.

Books

*van de Hulst, H.C., ''Light Scattering by Small Particles'', New York, ( Wiley, 1957;

Dover Dover ( ) is a town and major ferry port in Kent, southeast England. It faces France across the Strait of Dover, the narrowest part of the English Channel at from Cap Gris Nez in France. It lies southeast of Canterbury and east of Maidstone. ...

, 1981), . *van de Hulst, H.C., ''Multiple Light Scattering'', New York, Academic Press, 1980, .

Honors

Awards * Henry Draper Medal of the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...

(1955) * Eddington Medal of the

Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...

(1955) * Rumford Medal of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

(1964) *

Bruce Medal The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was ...

of the Astronomical Society of the Pacific (1978) * Karl Schwarzschild Medal of the Astronomische Gesellschaft (1995) Named after him *

Asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

2413 van de Hulst * van de Hulst approximation

Honors

* elected to the

American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...

(1960) * elected to the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (The Academy) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other ...

(1960) * elected to the United States

(1977)

References

Bibliography

* 1918 births 2000 deaths 20th-century Dutch astronomers Utrecht University alumni Academic staff of Leiden University Scientists from Utrecht (city) Foreign members of the Royal Society Foreign associates of the National Academy of Sciences Members of the Royal Netherlands Academy of Arts and Sciences {{Europe-astronomer-stub Members of the American Philosophical Society Optical physicists

Books

Honors

Honors

See also

References

Bibliography