Willem de Sitter

"de Sitter" redirects here. For other uses, seede Sitter (disambiguation).

Willem de Sitter
Born	(1872-05-06)6 May 1872 Sneek,Friesland,Netherlands
Died	20 November 1934(1934-11-20)(aged 62) Leiden,South Holland,Netherlands
Nationality	Dutch
Alma mater	Groningen University
Known for	de Sitter Universe
Scientific career
Fields	Physics
Doctoral advisor	Jacobus Kapteyn
Doctoral students	Dirk Brouwer Willem Hendrik van den Bos
Signature

Willem de Sitter(6 May 1872 – 20 November 1934) was a Dutchmathematician,physicist,andastronomer.

Life and work

Born inSneek,de Sitter studiedmathematicsat theUniversity of Groningenand then joined theGroningenastronomicallaboratory. He worked at theCape ObservatoryinSouth Africa(1897–1899). Then, in 1908, de Sitter was appointed to the chair of astronomy atLeiden University.He was director of theLeiden Observatoryfrom 1919 until his death.

De Sitter made major contributions to the field ofphysical cosmology.He co-authored a paper withAlbert Einsteinin 1932 in which they discussed the implications of cosmological data for the curvature of the universe. He also came up with the concept of thede Sitter spaceandde Sitter universe,a solution for Einstein'sgeneral relativityin which there is no matter and a positivecosmological constant.This results in an exponentially expanding, empty universe. De Sitter was also well-known for his research on the motions of the moons ofJupiter,invited to give theGeorge DarwinLecture at theRoyal Astronomical Societyin 1931.

Willem de Sitter died after a brief illness in November 1934.

Honours

In 1912, he became a member of theRoyal Netherlands Academy of Arts and Sciences.

Awards

• James Craig Watson Medal(1929)
• Bruce Medal(1931)
• Gold Medal of the Royal Astronomical Society(1931)
• Prix Jules Janssen,the highest award of theSociété astronomique de France,the French astronomical society (1934)

Named after him

• The craterDe Sitteron the Moon
• Asteroid1686 De Sitter
• De Sitter universe
• De Sitter space
• Anti-de Sitter space
• De Sitter invariant special relativity
• Einstein–de Sitter universe
• De Sitter double star experiment
• De Sitter precession
• De Sitter–Schwarzschild metric

Family

One of his sons,Ulbo de Sitter(1902 – 1980), was a Dutch geologist, and one of Ulbo's sons was a Dutch sociologistUlbo de Sitter(1930 – 2010).

Another son of Willem, Aernout de Sitter (1905 – 15 September 1944), was the director of theBosscha ObservatoryinLembang,Indonesia(then the Dutch East Indies), where he studied theMessier 4globular cluster.

Selected publications

Einstein, Ehrenfest, Willem de Sitter, Eddington, and Lorentz in Leiden (1923)

• De Sitter, W. (1911)."On the bearing of the Principle of Relativity on Gravitational Astronomy".Monthly Notices of the Royal Astronomical Society.71(5): 388–415.doi:10.1093/mnras/71.5.388.hdl:2027/mdp.39015019246357.
• De Sitter, W. (1913)."A proof of the constancy of the velocity of light".Proceedings of the Royal Netherlands Academy of Arts and Sciences.15(II): 1297–1298.Bibcode:1913KNAB...15.1297D.
  • "Ein astronomischer Beweis für die Konstanz der Lichtgeschwindigkeit"[An astronomical proof of the constancy of the speed of light].Physikalische Zeitschrift.14:429. 1913.
• "On the constancy of the velocity of light".Proceedings of the Royal Netherlands Academy of Arts and Sciences.16(I): 395–396. 1913.
• De Sitter, W. (1913)."Über die Genauigkeit, innerhalb welcher die Unabhängigkeit der Lichtgeschwindigkeit von der Bewegung der Quelle behauptet werden kann"[On the accuracy within which the independence of the speed of light from the motion of the source can be asserted].Physikalische Zeitschrift.14:1267.Bibcode:1913PhyZ...14.1267D.

• On Einstein's theory of gravitation and its astronomical consequences:
  1. De Sitter, W. (1916-07-14)."On Einstein's Theory of Gravitation and its Astronomical Consequences. First Paper".Monthly Notices of the Royal Astronomical Society.76(9): 699–728.Bibcode:1916MNRAS..76..699D.doi:10.1093/mnras/76.9.699.ISSN0035-8711– via Oxford University Press.
  2. De Sitter, W. (1916-12-08)."On Einstein's Theory of Gravitation and its Astronomical Consequences. Second Paper".Monthly Notices of the Royal Astronomical Society.77(2): 155–184.Bibcode:1916MNRAS..77..155D.doi:10.1093/mnras/77.2.155.ISSN0035-8711– via Oxford University Press.
  3. De Sitter, W. (1917-11-09)."On Einstein's Theory of Gravitation and its Astronomical Consequences. Third Paper".Monthly Notices of the Royal Astronomical Society.78(1): 3–28.Bibcode:1917MNRAS..78....3D.doi:10.1093/mnras/78.1.3.ISSN0035-8711– via Oxford University Press.

See also

• De Sitter double star experiment
• De Sitter precession
• De Sitter relativity
• De Sitter space
• De Sitter universe
• Anti-de Sitter space
• The Dreams in the Witch House,a story byH. P. Lovecraftfeaturing de Sitter, and inspired by his lectureThe Size of the Universe

External links

• O'Connor, John J.;Robertson, Edmund F.,"Willem de Sitter",MacTutor History of Mathematics Archive,University of St Andrews
• P.C. van der KruitWillem de Sitter (1872 – 1934)in: History of science and scholarship in the Netherlands.
• A. Blaauw,Sitter, Willem de (1872–1934),in Biografisch Woordenboek van Nederland.
• Bruce Medal page
• Awarding of Bruce Medal: PASP43(1931) 125
• Awarding of RAS gold medal: MNRAS91(1931) 422
• de Sitter's binary star arguments against Ritz's relativity theory (1913)Archived2009-01-29 at theWayback Machine(four articles)

Obituaries

• AN253(1934) 495/496(one line)
• JRASC29(1935) 1
• MNRAS95(1935) 343
• Obs58(1935) 22
• PASP46(1934) 368(one paragraph)
• PASP47(1935) 65