Willem de Sitter

Poll without page-refresh

Article on other languages:

	del.icio.us
	Digg
	Furl
	Reddit
	Rojo
	Add to OnlyWire

Willem de Sitter
A. Einstein, A.S. Eddington, P. Ehrenfest, H.A. Lorentz, W. de Sitter in Leiden (1920)
Born	May 6, 1872 Sneek
Died	November 20, 1934 Leiden
Nationality	Dutch
Fields	physics
Alma mater	Groningen University
Known for	de Sitter universe

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

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 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.

De Sitter died November 20, 1934 in Leiden.

1 Aernout de Sitter
2 Honours
3 Notes
4 See also
5 External links
- 5.1 Obituaries

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. 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 1944 ^{^[1]^[2]^[3]}.

Honours

Awards

James Craig Watson Medal (1929)
Bruce Medal (1931)
Gold Medal of the Royal Astronomical Society (1931)

Named after him

De Sitter crater on the Moon
Asteroid 1686 De Sitter

Notes

^ Obituary Notes of Astronomers at www.astro.uni-bonn.de
^ 1947BAN....10..287D Page 287 at articles.adsabs.harvard.edu
^ Adriaan, Blaauw (2004). "MY CRUISE THROUGH THE WORLD OF ASTRONOMY" (full text). Annual Review of Astronomy and Astrophysics 42 (1): 1. doi:10.1146/annurev.astro.42.053102.134020.