Herman Zanstra (November 3, 1894, Schoterland – October 2, 1972,

Haarlem Haarlem (; predecessor of ''Harlem'' in English language, English) is a List of cities in the Netherlands by province, city and Municipalities of the Netherlands, municipality in the Netherlands. It is the capital of the Provinces of the Nether ...

) was a

Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...

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 ...

. Zanstra was born near

Heerenveen Heerenveen (, ) is a town and Municipalities of the Netherlands, municipality in the Provinces of the Netherlands, province of Friesland (Fryslân), in the Northern Netherlands. In 2021, the town had a population of 29,790 (1 January) while the m ...

Friesland Friesland ( ; ; official ), historically and traditionally known as Frisia (), named after the Frisians, is a Provinces of the Netherlands, province of the Netherlands located in the country's northern part. It is situated west of Groningen (p ...

. In 1917 he graduated with an

Engineer's degree An engineer's degree is an advanced academic degree in engineering which is conferred in Europe, some countries of Asia and Latin America, North Africa and a few institutions in the United States. The degree may require a thesis but always require ...

chemical engineering Chemical engineering is an engineering field which deals with the study of the operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials ...

from the Delft Institute of Technology. While working in

Delft Delft () is a List of cities in the Netherlands by province, city and Municipalities of the Netherlands, municipality in the Provinces of the Netherlands, province of South Holland, Netherlands. It is located between Rotterdam, to the southeast, ...

for four years, the last two as a high school teacher, he wrote a highly theoretical and mathematical paper on relative motion which he sent to

William Francis Gray Swann W.F.G. Swann (August 29, 1884 – January 29, 1962) was an English physicist. Education He was educated at Brighton Technical College and the Royal College of Science, from which he obtained a B.Sc. in 1905. He worked as an assistant lect ...

. Swann, then offered him to earn a

Ph.D. A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

degree in theoretical physics with him at the

University of Minnesota The University of Minnesota Twin Cities (historically known as University of Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Twin Cities of Minneapolis and Saint ...

Minneapolis Minneapolis is a city in Hennepin County, Minnesota, United States, and its county seat. With a population of 429,954 as of the 2020 United States census, 2020 census, it is the state's List of cities in Minnesota, most populous city. Locat ...

, which he did in two years time by expanding on his paper (dissertation: ''A Study of Relative Motion in Connection with Classical Mechanics'', 1923). After another year with Swann, now in

Chicago Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...

, and a year at various labs in the Netherlands and Germany and two months at

Niels Bohr Niels Henrik David Bohr (, ; ; 7 October 1885 – 18 November 1962) was a Danish theoretical physicist who made foundational contributions to understanding atomic structure and old quantum theory, quantum theory, for which he received the No ...

's lab in

Copenhagen Copenhagen ( ) is the capital and most populous city of Denmark, with a population of 1.4 million in the Urban area of Copenhagen, urban area. The city is situated on the islands of Zealand and Amager, separated from Malmö, Sweden, by the ...

, he became a postdoc at

Caltech The California Institute of Technology (branded as Caltech) is a private university, private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small g ...

. Here he wrote a famous paper, ''An Application of the Quantum Theory to the Luminosity of Diffuse Nebulae'', which for the first time provided a quantitative method (the " Zanstra method") for understanding the luminosity of

nebula A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...

s and

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

s. After teaching briefly at the

University of Washington The University of Washington (UW and informally U-Dub or U Dub) is a public research university in Seattle, Washington, United States. Founded in 1861, the University of Washington is one of the oldest universities on the West Coast of the Uni ...

he went to London and eventually to the

University of Amsterdam The University of Amsterdam (abbreviated as UvA, ) is a public university, public research university located in Amsterdam, Netherlands. Established in 1632 by municipal authorities, it is the fourth-oldest academic institution in the Netherlan ...

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

left him stranded in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

, and he therefore took up a teaching position in

Durban Durban ( ; , from meaning "bay, lagoon") is the third-most populous city in South Africa, after Johannesburg and Cape Town, and the largest city in the Provinces of South Africa, province of KwaZulu-Natal. Situated on the east coast of South ...

, but returned to Europe after the war. In 1949 he became member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences (, KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed in the Trippenhuis in Amsterdam. In addition to various advisory a ...

. He won the

Gold Medal of the Royal Astronomical Society The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...

in 1961. The lunar crater Zanstra is named after him, as is

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 ...

2945 Zanstra.

References

Sources

Bio and discussion of the Zanstra method
{{DEFAULTSORT:Zanstra, Herman 1894 births 1972 deaths University of Minnesota College of Science and Engineering alumni 20th-century Dutch astronomers Delft University of Technology alumni Members of the Royal Netherlands Academy of Arts and Sciences People from Heerenveen Recipients of the Gold Medal of the Royal Astronomical Society