Knut Emil Lundmark (14 June 1889 in

Älvsbyn Älvsbyn (; translating to "the river village") is a locality and the seat of Älvsbyn Municipality in Norrbotten County, Sweden with 4,967 inhabitants in 2010. It is known as "The Pearl of Norrbotten". Älvsbyn has a railway station that is serv ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

– 23 April 1958 in

Lund Lund (, ;"Lund"
(US) and ) is a city in the provinces of Sweden, province of Scania, southern Swed ...

, Sweden), was a Swedish

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 ...

, professor of astronomy and head of the

observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Th ...

Lund University Lund University () is a Public university, public research university in Sweden and one of Northern Europe's oldest universities. The university is located in the city of Lund in the Swedish province of Scania. The university was officially foun ...

from 1929 to 1955. Lundmark received his astronomical education at the

Uppsala University Uppsala University (UU) () is a public university, public research university in Uppsala, Sweden. Founded in 1477, it is the List of universities in Sweden, oldest university in Sweden and the Nordic countries still in operation. Initially fou ...

. His dissertation (1920) was titled: ''The relations of the globular clusters and spiral nebulae to the stellar system''. During the 1920s he worked at several observatories in the

USA The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

, mainly the

Lick Observatory The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton (California), Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The ...

and the

Mount Wilson Observatory The Mount Wilson Observatory (MWO) is an Observatory#Astronomical observatories, astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson (California), Mount Wilson, a peak in the San Gabrie ...

. Knut Lundmark was one of the pioneers in the modern study of the galaxies and their distances. He was one of the first to suspect that the galaxies are remote stellar systems at vast distances and not nearby objects belonging to our own galaxy, the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

. In 1919 he measured the distance to M31 – the

Andromeda Galaxy The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a Galaxy#Isophotal diameter, D25 isop ...

, to 650,000 light years (about a fourth of the present day value) using magnitudes of

nova A nova ( novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new") that slowly fades over weeks or months. All observed novae involve white ...

e found in M31 and comparing them to nearby ones with known distances. Lundmark's work contributed to the later famous Great Debate over whether

nebulae 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 th ...

were galaxies or concentrations of glowing gas. Lundmark also studied the light distribution in the galaxies, and discovered that the distribution could only properly be explained if the galaxies contained vast amounts of light-blocking dark clouds. He was the leading writer of

popular astronomy Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers m ...

among the professional astronomers in Sweden from the 1930s and onwards. He also often appeared in the Swedish national radio with programs on popular astronomy and the history of science. He made generations of Swedes fascinated and interested in astronomy. The lunar crater '' Lundmark'' and the minor planet 1334 Lundmarka were named after him. The Wolf-Lundmark-Melotte Galaxy is named after Lundmark,

Max Wolf Maximilian Franz Joseph Cornelius Wolf (21 June 1863 – 3 October 1932) was a German astronomer and a pioneer in the field of astrophotography. He was the chairman of astronomy at the University of Heidelberg and director of the Heidelberg-K� ...

and

Philibert Jacques Melotte Philibert Jacques Melotte (29 January 1880 – 30 March 1961) was a British astronomer whose parents emigrated from Belgium. In 1908 he discovered a natural satellite, moon of Jupiter, today known as Pasiphaë (moon), Pasiphaë. It was simp ...

. Lundmark is also widely known by Chinese astronomers for his great work on the catalogue of novae.

Dark matter

A recently found publication from 1930 shows Knut Lundmark to be the first to realise that the universe must contain much more mass than we can observe, now known as

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

References

External links

photo
Knut Lundmark at Lund Observatory in 1937
History from Uppsala Observatory

{{DEFAULTSORT:Lundmark, Knut 1889 births 1958 deaths 20th-century Swedish astronomers People from Älvsbyn Municipality