Willem de Sitter

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Willem de Sitter
Born (1872-05-06)6 May 1872
Died 20 November 1934(1934-11-20) (aged 62)
Nationality Dutch
Alma mater Groningen University
Known for de Sitter universe
Scientific career
Fields physics

Willem de Sitter (6 May 1872 – 20 November 1934) was a Dutch mathematician, physicist and astronomer.

Life and work

Born in Sneek, De Sitter studied mathematics at the University of Groningen and then joined the Groningen astronomical laboratory. He worked at the Cape Observatory in South Africa (1897–1899). Then, in 1908, de Sitter was appointed to the chair of astronomy at Leiden University. He was director of the Leiden Observatory from 1919 until his death.

De Sitter made major contributions to the field of physical cosmology. 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. He also came up with the concept of the de Sitter space and de Sitter universe, a solution for Einstein's general relativity in which there is no matter and a positive cosmological constant. This results in an exponentially expanding, empty universe. De Sitter was also famous for his research on the planet Jupiter.

Einstein, Ehrenfest, De Sitter, Eddington & Lorentz in Leiden (1923)

Willem de Sitter died after a brief illness in November 1934.[1][2][3]


One of his sons, Ulbo de Sitter (1902-1980) was a Dutch geologist, and one of his sons is the Dutch sociologist Ulbo de Sitter (1930-2010). Another son Aernout de Sitter (1905 – 15 September 1944[4]), was director of the Bosscha Observatory in Lembang, Indonesia (then the Dutch East Indies), where he studied the M4 globular cluster.



Named after him

See also

Selected Publications


  1. Obituary Notes of Astronomers at www.astro.uni-bonn.de
  2. 1947BAN....10..287D Page 287 at articles.adsabs.harvard.edu
  3. Lua error in Module:Citation/CS1 at line 746: Argument map not defined for this variable.
  4. Obituary Notes of Astronomers at www.astro.uni-bonn.de

External links