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Willem de Sitter
A. Einstein, A.S. Eddington, P. Ehrenfest, H.A. Lorentz, W. de Sitter in Leiden (1920)
A. Einstein, A.S. Eddington, P. Ehrenfest, H.A. Lorentz, W. Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical Sir Arthur Stanley Eddington, OM (28 December 1882 – 22 November 1944 was an English Astrophysicist of the early 20th century Paul Ehrenfest ( January 18, 1880 – September 25, 1933) was an Austrian Physicist and Mathematician, who Hendrik Antoon Lorentz ( July 18, 1853 &ndash February 4, 1928) was a Dutch Physicist who shared the 1902 Nobel de Sitter in Leiden (1920)
BornMay 6, 1872
Sneek
DiedNovember 20, 1934
Leiden
NationalityDutch
Fieldsphysics
Alma materGroningen University
Known forde Sitter universe

Willem de Sitter (May 6, 1872 – November 20, 1934) was a Dutch mathematician, physicist and astronomer. Events 1527 - Spanish and German troops sack Rome; some consider this the end of the Renaissance. Year 1872 ( MDCCCLXXII) was a Leap year starting on Monday (link will display the full calendar of the Gregorian Calendar (or a Leap year Sneek ( Snits is a Municipality and a City in the province of Friesland (Fryslân in the northern Netherlands. Events 284 - Diocletian was chosen as Roman Emperor. 762 - Bögü Khan of the Uyghurs, Year 1934 ( MCMXXXIV) was a Common year starting on Monday (link will display full 1934 calendar of the Gregorian calendar. "Leyden" redirects here For other uses see Leyden (disambiguation. The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. Alma mater is Latin for "nourishing mother" It was used in Ancient Rome as a title for the mother Goddess, and in Medieval The University of Groningen (Rijksuniversiteit Groningen located in the city of Groningen, was founded in 1614. A de Sitter universe is a solution to Einstein 's field equations of General Relativity which is named after Willem de Sitter. Events 1527 - Spanish and German troops sack Rome; some consider this the end of the Renaissance. Year 1872 ( MDCCCLXXII) was a Leap year starting on Monday (link will display the full calendar of the Gregorian Calendar (or a Leap year Events 284 - Diocletian was chosen as Roman Emperor. 762 - Bögü Khan of the Uyghurs, Year 1934 ( MCMXXXIV) was a Common year starting on Monday (link will display full 1934 calendar of the Gregorian calendar. The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands

Born in Sneek, De Sitter studied mathematics at the University of Groningen and then joined the Groningen astronomical laboratory. Sneek ( Snits is a Municipality and a City in the province of Friesland (Fryslân in the northern Netherlands. Mathematics is the body of Knowledge and Academic discipline that studies such concepts as Quantity, Structure, Space and The University of Groningen (Rijksuniversiteit Groningen located in the city of Groningen, was founded in 1614. Groningen is the capital city of the province of Groningen in the Netherlands. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study He worked at the Cape Observatory in South Africa (1897-1899). An observatory is a location used for observing terrestrial and/or celestial events The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Then, in 1908, de Sitter was appointed to the chair of astronomy at Leiden University. Leiden University (Universiteit Leiden located in the city of Leiden, is the oldest University in The Netherlands. He was director of the Leiden Observatory from 1919 until his death.

De Sitter made major contributions to the field of physical cosmology. Physical cosmology, as a branch of Astronomy, is the study of the large-scale structure of the Universe and is concerned with fundamental questions about its He co-authored a paper with Albert Einstein in 1932 in which they argued that there might be large amounts of matter which do not emit light, now commonly referred to as dark matter. In Physics and cosmology, dark matter is hypothetical Matter that does not interact with the electromagnetic force but whose presence can be inferred from He also came up with the concept of the de Sitter universe, a solution for Einstein's general relativity in which there is no matter and a positive cosmological constant. A de Sitter universe is a solution to Einstein 's field equations of General Relativity which is named after Willem de Sitter. In Physical cosmology, the cosmological constant (usually denoted by the Greek capital letter Lambda: Λ was proposed by Albert Einstein as a modification This results in an exponentially expanding, empty universe. De Sitter was also famous for his research on the planet Jupiter.

De Sitter died November 20, 1934 in Leiden. Events 284 - Diocletian was chosen as Roman Emperor. 762 - Bögü Khan of the Uyghurs, Year 1934 ( MCMXXXIV) was a Common year starting on Monday (link will display full 1934 calendar of the Gregorian calendar. "Leyden" redirects here For other uses see Leyden (disambiguation.

Contents

Aernout de Sitter

His son, Aernout de Sitter, was director of the Bosscha Observatory in Lembang, Indonesia (then the Dutch East Indies), where he studied the M4 globular cluster. Bosscha Observatory is the oldest Observatory in Indonesia. The observatory is located in Lembang, West Java, approximately north of The Republic of Indonesia ( (Republik Indonesia is a Country in Southeast Asia. Messier 4 (also known as M4 or NGC 6121) is a Globular cluster in the Constellation Scorpius. A globular cluster is a spherical collection of Stars that orbits a galactic core as a Satellite. He was captured by the Japanese when they invaded at the outset of World War II, and died in a Sumatra labour camp in September of 1944 [1] [2] [3]. For a topic outline on this subject see List of basic Japan topics. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including Sumatra (also spelled Sumatera) is the sixth largest island in the world (approximately 470000 km² and is the largest island entirely in Indonesia (two

Honours

Awards

Named after him

See also

External links

Obituaries

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