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 – 23 April 1958 in Lund, Sweden), was a Swedish
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...
, professor of astronomy and head of the observatory at
Lund University
, motto = Ad utrumque
, mottoeng = Prepared for both
, established =
, type = Public research university
, budget = SEK 9 billion observatory of
Uppsala University
Uppsala University ( sv, Uppsala universitet) is a public research university in Uppsala, Sweden. Founded in 1477, it is the oldest university in Sweden and the Nordic countries still in operation.
The university rose to significance during ...
. 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 (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
Mount Wilson Observatory
The Mount Wilson Observatory (MWO) is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles.
The observat ...
.
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 is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...
. In 1919 he measured the distance to M31 – the
Andromeda Galaxy
The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gal ...
, to 650,000 light years (about a fourth of the present day value) using magnitudes of novae 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 ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ 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 region ...
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 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 and Philibert Jacques Melotte.
Lundmark is also widely known by Chinese astronomers as 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
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not a ...