Willem de Sitter facts for kids

Quick facts for kids 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

Physical cosmology

Universe · Big Bang Age of the universe Timeline of the Big Bang Ultimate fate of the universe Early universe Inflation · Nucleosynthesis GWB · Neutrino background Cosmic microwave background Expanding universe Redshift · Hubble's law Metric expansion of space Friedmann equations FLRW metric Structure Formation Shape of the universe Structure formation Reionization Galaxy formation Large-scale structure Galaxy filaments Components Lambda-CDM model Dark energy · Dark matter Timeline Timeline of cosmological theories Timeline of the Big Bang Future of an expanding universe Experiments Observational cosmology 2dF · SDSS COBE · BOOMERanG · WMAP · Planck Scientists Isaac Newton · Einstein · Hawking · Friedman · Lemaître · Hubble · Penzias · Wilson · Gamow · Dicke · Zel'dovich · Mather · Rubin · Smoot

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 discussed the implications of cosmological data for the curvature of the universe. 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 motions of the moons of Jupiter.

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

Honours

In 1912, he became a member of the Royal 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 the Société astronomique de France, the French astronomical society (1934)

Named after him

• The crater De Sitter on the Moon
• Asteroid 1686 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 Ulbos's sons was a Dutch sociologist Ulbo de Sitter (1930 – 2010).

Another son of Willem, Aernout de Sitter (1905 – 15 September 1944), was the director of the Bosscha Observatory in Lembang, Indonesia (then the Dutch East Indies), where he studied the Messier 4 globular cluster.

Selected publications

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

• On Einstein's theory of gravitation and its astronomical consequences:

See also

In Spanish: Willem de Sitter para niños

• 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 by H. P. Lovecraft featuring de Sitter, and inspired by his lecture The Size of the Universe