Herman Zanstra
Encyclopedia
Herman Zanstra was a Dutch
astronomer
.
Zanstra was born near Heerenveen
in Friesland
. In 1917 he graduated with an Engineer's degree
in chemical engineering
from the Delft Institute of Technology. While working in Delft
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
. Swann, then offered him to earn a Ph.D.
degree in theoretical physics with him at the University of Minnesota
at Minneapolis, 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
, and a year at various labs in the Netherlands and Germany and two months at Niels Bohr
's lab in Copenhagen
, he became a postdoc at Caltech. 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
s and comet
s.
After teaching briefly at the University of Washington
he went to London and eventually to the University of Amsterdam. World War II
left him stranded in South Africa
, and he therefore took up a teaching position in Durban
, but returned to Europe after the war.
He won the Gold Medal of the Royal Astronomical Society
in 1961.
The crater Zanstra
on the Moon
is named after him.
Dutch people
The Dutch people are an ethnic group native to the Netherlands. They share a common culture and speak the Dutch language. Dutch people and their descendants are found in migrant communities worldwide, notably in Suriname, Chile, Brazil, Canada, Australia, South Africa, New Zealand, and the United...
astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
.
Zanstra was born near Heerenveen
Heerenveen
Heerenveen is a town in the Heerenveen municipality of the province of Friesland , in the north of the Netherlands.- History :The town was established in 1551 by three lords as a location for the purpose of digging peat which was used for fuel, hence the name...
in Friesland
Friesland
Friesland is a province in the north of the Netherlands and part of the ancient region of Frisia.Until the end of 1996, the province bore Friesland as its official name. In 1997 this Dutch name lost its official status to the Frisian Fryslân...
. In 1917 he graduated with an Engineer's degree
Engineer's degree
An engineer's degree is an advanced academic degree in engineering that is conferred in Europe, some countries of Latin America, and a few institutions in the United States....
in chemical engineering
Chemical engineering
Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...
from the Delft Institute of Technology. While working in Delft
Delft
Delft is a city and municipality in the province of South Holland , the Netherlands. It is located between Rotterdam and The Hague....
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
William Francis Gray Swann
William Francis Gray Swann was an Anglo-American physicist. 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 Lecturer at the University of Sheffield, while simultaneously pursuing a doctorate at...
. Swann, then offered him to earn a Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
degree in theoretical physics with him at the University of Minnesota
University of Minnesota
The University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...
at Minneapolis, 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
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
, and a year at various labs in the Netherlands and Germany and two months at Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...
's lab in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
, he became a postdoc at Caltech. 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
Zanstra method
The Zanstra method is a method to determine the temperature of central stars of planetary nebula.It was developed by Herman Zanstra in 1927.It is assumed that the nebula is optically thick in the Lyman continuum which means that all ionizing photons from the central star are absorbed inside the...
") for understanding the luminosity of nebula
Nebula
A nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
s and comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s.
After teaching briefly at the University of Washington
University of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
he went to London and eventually to the University of Amsterdam. World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
left him stranded in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, and he therefore took up a teaching position in Durban
Durban
Durban is the largest city in the South African province of KwaZulu-Natal and the third largest city in South Africa. It forms part of the eThekwini metropolitan municipality. Durban is famous for being the busiest port in South Africa. It is also seen as one of the major centres of tourism...
, but returned to Europe after the war.
He won the Gold Medal of the Royal Astronomical Society
Gold Medal of the Royal Astronomical Society
-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
in 1961.
The crater Zanstra
Zanstra (crater)
Zanstra is a lunar crater that is located on the far side of the Moon. It lies to the southeast of the crater pair Ibn Firnas and King, and northwest of Gregory. This is a low, eroded formation that is difficult to distinguish from its surroundings...
on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
is named after him.