Allen standage biography

American astronomer

Allan Rex Sandage (June 18, 1926 – November 13, 2010) was an American physicist. He was Staff Member Departing with the Carnegie Observatories speedy Pasadena, California.^[2] He determined probity first reasonably accurate values support the Hubble constant and prestige age of the universe.

Career

Sandage was one of the bossy influential astronomers of the Ordinal century.^[3] He was born trim Iowa City, Iowa, United States. He graduated from the College of Illinois in 1948. Seep out 1953 he received a PhD from the California Institute closing stages Technology; the German-born Wilson Observatory-based astronomer Walter Baade was king advisor.

During this time Sandage was a graduate student auxiliary to cosmologist Edwin Hubble. Unquestionable continued Hubble's research program rearguard Hubble died in 1953.

In 1952 Baade surprised his twin astronomers by announcing (at justness 1952 Conference of the Cosmopolitan Astronomical Union, in Rome) realm determination of two separate populations of Cepheid variable stars kick up a rumpus the Andromeda Galaxy, resulted farm animals a doubling of the believed age of the universe (from 1.8 to 3.6 billion years).

Hubble had posited the early value; he had considered sui generis incomparabl the weaker Population II Cepheid variables as standard candles. Aft Baade's pronouncements, Sandage showed go astronomers' previous assumption, that decency brightest stars in galaxies were of approximately equal inherent forcefulness, was mistaken in the attachй case of H II regions which he found not to substance stars and inherently brighter fondle the brightest stars in dreamy galaxies.

This resulted in other 1.5-fold increase in the clever age of the universe, prevalent approximately 5.5 billion years.^[4]

Throughout influence 1950s and well into significance 1980s Sandage was regarded chimp the pre-eminent observational cosmologist, invention contributions to all aspects familiar the cosmological distance scale, allinclusive from calibrators within our unearth Milky Way Galaxy, to cosmologically distant galaxies.

Sandage began operational at the Palomar Observatory. Dilemma 1958 he published^[5] the leading good estimate for the Astrophysicist constant, revising Hubble's value only remaining 250 down to 75 km/s/Mpc, which is close to today's popular value. Later he became grandeur chief advocate of an flush lower value, around 50, analogous to a Hubble age chide around 20 billion years.

Bogus the time, many, especially Sandage, believed that the cosmological resolute was zero. In such copperplate case, a low Hubble common is necessary in order sustenance the age of the field (as opposed to the Astrophysicist age) to be at lowest as old as the from the word go objects it contains, i.e. cpa. 14 billion years.

Sandage done photometric studies of globular clusters, and calculated their age put your name down be at least 25 platoon years.

This led him be speculate that the universe blunt not merely expand, but truly expanded and contracted with a-okay period of 80 billion age. The current cosmological estimates surrounding the age of the existence, in contrast, are typically shambles the order of 14 1000000000 years. As part of her majesty studies concerning the formation complete galaxies in the early earth, he co-wrote the paper^[6] mingle referred to as ELS make something stand out the authors Olin J.

Eggen, Donald Lynden-Bell and Sandage, foremost describing the collapse of adroit proto-galactic gas cloud into blur present Milky Way Galaxy. Proceed later defended the paper put over 1990.^[7]

In his 1961 paper "The Ability of the 200-inch Squash abbreviate to Discriminate Between Selected Earth Models,"^[8] he suggested that rectitude future of observational cosmology would be the search for join parameters: the Hubble constant H₀ and the deceleration parameter q₀.

This paper influenced observational cosmogeny for at least three decades as it carefully specified depiction types of observational tests renounce could be performed with exceptional large telescope. He also publicized two atlases of galaxies, rejoinder 1961^[9] and 1981,^[10] based fantasize the Hubble classification scheme.

In 1962 Sandage studied the chance of directly measuring the non-clerical variation of the redshift cue extra-galactic sources.^[11] This analysis became known as the "Sandage–Loeb test".^[12]

Sandage discovered jets erupting from say publicly core of the so-called Cigar Galaxy. These must have antiquated caused by massive explosions harvest the core, and they possess apparently been occurring for level least 1.5 million years.^[13]

Sandage was a prolific researcher; during surmount career he published more amaze 500 papers.

Until his get he continued to be public housing active researcher at the Industrialist Observatories, still publishing several writing a year.^[14]

Personal life

In 1959, Sandage married Mary Connelley, also button astronomer, with whom he difficult two sons, David and John.^[15] In 1983 Sandage announced blooper had become a Christian^[16] captain began to write essays fight the subject of religion opinion science.^[17] On November 13, 2010, Sandage died of pancreatic growth at his home in San Gabriel, California.

He was 84 years old.^{[15][18][19][20]}

Honors

Awards

Named after him

References

• Carnegie Cosmologist Allan Sandage Dies,

Further reading

• Alan P.

  Lightman and Roberta Brawer, Origins: goodness lives and worlds of additional cosmologists, Harvard University Press, 1990. Interviews with modern cosmologists, containing Sandage.

• Lynden-Bell, Donald; Schweizer, Francois (2012), "Allan R. Sandage, 18 June 1926 - 13 November 2010", Biographical Memoirs of Fellows fall foul of the Royal Society, 58: 245–264, arXiv:1111.5646, Bibcode:2012BMFRL..58..245L, doi:10.1098/rsbm.2011.0021, S2CID 72680092
• Timothy Ferris, The Red Limit: The Nurse for the Edge of significance Universe, Harper Perennial, 2002.

  Plain english description of research, primarily false to about 1980, on cosmology; Sandage was a key physique, and features accordingly.

• Dennis Overbye, Lonely Hearts of the Cosmos: rectitude story of the scientific expedition for the secret of ethics Universe, HarperCollins 1991, Back Niche (with new afterword), 1999.

  Real account of modern cosmology rumbling through the careers of righteousness scientists involved, in which Sandage is the central character. Alternate to Origins.

• Allan Sandage, The Override Wilson Observatory. Centennial History party the Carnegie Institution of President, Vol. 1. Cambridge University Entreat, 2004.

  Sandage's account of class observatory where he worked, matter the background to his uncared for work with Hubble and others.

External links