Allan Rex Sandage (June 18, 1926 – November 13, 2010) was an American
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
. He was Staff Member
Emeritus
''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...
with the
Carnegie Observatories
The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...
in
Pasadena, California
Pasadena ( ) is a city in Los Angeles County, California, northeast of downtown Los Angeles. It is the most populous city and the primary cultural center of the San Gabriel Valley. Old Pasadena is the city's original commercial district.
I ...
. He determined the first reasonably accurate values for the
Hubble constant
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving ...
and the
age of the universe
In physical cosmology, the age of the universe is the time elapsed since the Big Bang. Astronomers have derived two different measurements of the age of the universe:
a measurement based on direct observations of an early state of the universe, ...
.
Career
Sandage was one of the most influential astronomers of the 20th century. He was born in
Iowa City, Iowa
Iowa City, offically the City of Iowa City is a city in Johnson County, Iowa, United States. It is the home of the University of Iowa and county seat of Johnson County, at the center of the Iowa City Metropolitan Statistical Area. At the time ...
,
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. He graduated from the
University of Illinois
The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the University ...
in 1948. In 1953 he received a
PhD PHD or PhD may refer to:
* Doctor of Philosophy (PhD), an academic qualification
Entertainment
* '' PhD: Phantasy Degree'', a Korean comic series
* ''Piled Higher and Deeper'', a web comic
* Ph.D. (band), a 1980s British group
** Ph.D. (Ph.D. albu ...
from the
California Institute of Technology
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
; the
German
German(s) may refer to:
* Germany (of or related to)
**Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ger ...
-born Wilson Observatory-based astronomer
Walter Baade
Wilhelm Heinrich Walter Baade (March 24, 1893 – June 25, 1960) was a German astronomer who worked in the United States from 1931 to 1959.
Biography
The son of a teacher, Baade finished school in 1912. He then studied maths, physics and astro ...
was his advisor. During this time Sandage was a graduate student assistant to cosmologist
Edwin Hubble
Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an Americans, American astronomer. He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology.
Hubble proved that many objects ...
. He continued Hubble's research program after Hubble died in 1953. In 1952 Baade surprised his fellow astronomers by announcing (at the 1952 Conference of the
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
, in Rome) his determination of two separate populations of
Cepheid variable
A Cepheid variable () is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.
A strong direct relationship between a Cepheid varia ...
stars in the
Andromeda Galaxy
The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ...
, resulted in a doubling of the estimated
age of the universe
In physical cosmology, the age of the universe is the time elapsed since the Big Bang. Astronomers have derived two different measurements of the age of the universe:
a measurement based on direct observations of an early state of the universe, ...
(from 1.8 to 3.6 billion years). Hubble had posited the earlier value; he had considered only the weaker Population II Cepheid variables as
standard candles. After Baade's pronouncements, Sandage showed that astronomers' previous assumption, that the brightest stars in galaxies were of approximately equal inherent intensity, was mistaken in the case of
H II region
An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds ...
s which he found not to be stars and inherently brighter than the brightest stars in distant galaxies. This resulted in another 1.5-fold increase in the calculated age of the universe, to approximately 5.5 billion years. Throughout the 1950s and well into the 1980s Sandage was regarded as the pre-eminent observational
cosmologist
Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...
, making contributions to all aspects of the cosmological distance scale, ranging from calibrators within our own
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...
Galaxy, to cosmologically distant galaxies.
Sandage began working at the
Palomar Observatory
Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...
. In 1958 he published the first good estimate for the
Hubble constant
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving ...
, revising Hubble's value of 250 down to 75 km/s/Mpc, which is close to today's accepted value. Later he became the chief advocate of an even lower value, around 50, corresponding to a
Hubble age
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving a ...
of around 20 billion years. At the time, many, especially Sandage, believed that the
cosmological constant
In cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: ), alternatively called Einstein's cosmological constant,
is the constant coefficient of a term that Albert Einstein temporarily added to his field equ ...
was zero. In such a case, a low Hubble constant is necessary in order for the age of the universe (as opposed to the
Hubble age
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving a ...
) to be at least as old as the oldest objects it contains, i.e. ca. 14 billion years.
Sandage performed photometric studies of
globular cluster
A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...
s, and calculated their age to be at least 25 billion years. This led him to speculate that the universe did not merely expand, but actually expanded and contracted with a period of 80 billion years. The current cosmological estimates of the age of the universe, in contrast, are typically of the order of 14 billion years. As part of his studies concerning the formation of galaxies in the early universe, he co-wrote the paper now referred to as ELS after the authors
Olin J. Eggen,
Donald Lynden-Bell
Donald Lynden-Bell CBE FRS (5 April 1935 – 6 February 2018) was a British theoretical astrophysicist. He was the first to determine that galaxies contain supermassive black holes at their centres, and that such black holes power quasars. Ly ...
and Sandage, first describing the collapse of a proto-galactic gas cloud into our present Milky Way Galaxy. He later defended the paper in 1990.
In his 1961 paper "The Ability of the 200-inch Telescope to Discriminate Between Selected World Models," he suggested that the future of observational cosmology would be the search for two parameters: the
Hubble constant
Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving ...
H
0 and the
deceleration parameter
The deceleration parameter ''q'' in cosmology is a dimensionless measure of the cosmic acceleration of the expansion of space in a Friedmann–Lemaître–Robertson–Walker universe. It is defined by:
:q \ \stackrel\ -\frac
where a is the sca ...
q
0. This paper influenced observational cosmology for at least three decades as it carefully specified the types of observational tests that could be performed with a large telescope. He also published two atlases of galaxies, in 1961 and 1981, based on the
Hubble classification
The Hubble sequence is a morphological classification scheme for galaxies invented by Edwin Hubble in 1926. It is often colloquially known as the Hubble tuning-fork diagram because the shape in which it is traditionally represented resembles a t ...
scheme.
In 1962 Sandage studied the possibility of directly measuring the temporal variation of the redshift of extra-galactic sources. This analysis became known as the "Sandage–Loeb test".
Sandage discovered jets erupting from the core of the so-called
Cigar Galaxy
Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. It is the second-largest member of the M81 Group, with the Galaxy#Isophotal diameter, D25 i ...
. These must have been caused by massive explosions in the core, and they have apparently been occurring for at least 1.5 million years.
Sandage was a prolific researcher; during his career he published more than 500 papers. Until his death he continued to be an active researcher at the
Carnegie Observatories
The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...
, still publishing several papers a year.
Personal life
In 1959, Sandage married Mary Connelley, also an astronomer, with whom he had two sons, David and John.
In 1983 Sandage announced he had become a
Christian
Christians () are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words ''Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χρι ...
and began to write essays on the subject of religion and science. On November 13, 2010, Sandage died of
pancreatic cancer
Pancreatic cancer arises when cell (biology), cells in the pancreas, a glandular organ behind the stomach, begin to multiply out of control and form a Neoplasm, mass. These cancerous cells have the malignant, ability to invade other parts of t ...
at his home in
San Gabriel, California
San Gabriel (Spanish for " St. Gabriel") is a city located in the San Gabriel Valley of Los Angeles County, California. At the 2010 census, the population was 39,718.
San Gabriel was founded by the Spanish in 1771, when Mission San Gabriel Arc ...
. He was 84 years old.
Honors
Awards
*
Helen B. Warner Prize for Astronomy
The Helen B. Warner Prize for Astronomy is awarded annually by the American Astronomical Society to a young astronomer (aged less than 36,
or within 8 years of the award of their PhD) for a significant contribution to observational or theoretical ...
(1957)
*Member of the
American Philosophical Society
The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...
(1962)
*Member of the
National Academy of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
(1963)
*
Eddington Medal
The Eddington Medal is awarded by the Royal Astronomical Society for investigations of outstanding merit in theoretical astrophysics. It is named after Sir Arthur Eddington. First awarded in 1953, the frequency of the prize has varied over the year ...
(1963)
*
Gold Medal of the Royal Astronomical Society
The Gold Medal of the Royal Astronomical Society is the highest award given by the Royal Astronomical Society (RAS). The RAS Council have "complete freedom as to the grounds on which it is awarded" and it can be awarded for any reason. Past awar ...
(1967)
*
National Medal of Science
The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral and social scienc ...
(1970)
*
Henry Norris Russell Lectureship The Henry Norris Russell Lectureship is awarded each year by the American Astronomical Society in recognition of a lifetime of excellence in astronomical research. The idea for the lectureship came from then society President Harlow Shapley in 1945, ...
(1972)
*
Elliott Cresson Medal
The Elliott Cresson Medal, also known as the Elliott Cresson Gold Medal, was the highest award given by the Franklin Institute. The award was established by Elliott Cresson, life member of the Franklin Institute, with $1,000 granted in 1848. The ...
(1973)
*Fellow of the
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
*
Bruce Medal
The Catherine Wolfe Bruce Gold Medal is awarded every year by the Astronomical Society of the Pacific for outstanding lifetime contributions to astronomy. It is named after Catherine Wolfe Bruce, an American patroness of astronomy, and was firs ...
(1975)
* Golden Plate Award of the
American Academy of Achievement
The American Academy of Achievement, colloquially known as the Academy of Achievement, is a non-profit educational organization that recognizes some of the highest achieving individuals in diverse fields and gives them the opportunity to meet o ...
(1976)
*
Crafoord Prize
The Crafoord Prize is an annual science prize established in 1980 by Holger Crafoord, a Swedish industrialist, and his wife Anna-Greta Crafoord. The Prize is awarded in partnership between the Royal Swedish Academy of Sciences and the Crafoord Foun ...
(1991)
*Member of the
American Philosophical Society
The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...
(1995)
*
Gruber Prize in Cosmology
The Gruber Prize in Cosmology, established in 2000, is one of three prestigious international awards worth US$500,000 made by the Gruber Foundation, a non-profit organization based at Yale University in New Haven, Connecticut.
Since 2001, the G ...
(2000)
Named after him
*
Main-belt asteroid
The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...
,
9963 Sandage
9963 Sandage, provisional designation , is a stony Phocaea asteroid from the inner regions of the asteroid belt, approximately 6 kilometers in diameter.
It was discovered by American astronomer Eleanor Helin at the Palomar Observatory in Califo ...
(1992 AN)
References
*
Further reading
*Alan P. Lightman and Roberta Brawer, ''Origins: the lives and worlds of modern cosmologists'', Harvard University Press, 1990. Interviews with modern cosmologists, including Sandage.
*
*
Timothy Ferris
Timothy Ferris (born August 29, 1944) is an American science writer and the best-selling author of twelve books, including ''The Science of Liberty'' (2010) and ''Coming of Age in the Milky Way'' (1988), for which he was awarded the American ...
, ''The Red Limit: The Search for the Edge of the Universe,'' Harper Perennial, 2002. Non-technical description of research, primarily up to about 1980, on cosmology; Sandage was a key figure, and features accordingly.
*
Dennis Overbye
Dennis Overbye (born June 2, 1944, in Seattle, Washington) is a science writer specializing in physics and cosmology and is the cosmic affairs correspondent for ''The New York Times''.
Biography
Overbye received his B.S. in physics from M.I.T.— ...
, ''Lonely Hearts of the Cosmos: the story of the scientific quest for the secret of the Universe'', HarperCollins 1991, Back Bay (with new afterword), 1999. Historical account of modern cosmology told through the careers of the scientists involved, in which Sandage is the central character. Complementary to ''Origins''.
*Allan Sandage, ''The Mount Wilson Observatory''. Centennial History of the Carnegie Institution of Washington, Vol. 1. Cambridge University Press, 2004. Sandage's account of the observatory where he worked, with the background to his own work with Hubble and others.
External links
Bruce Medalist page on Allan SandageAllan Sandage directory page at the IAUAllan Sandage page at The Carnegie Observatories*
{{DEFAULTSORT:Sandage, Allan R.
People from Iowa City, Iowa
20th-century American astronomers
21st-century American astronomers
American cosmologists
Discoverers of asteroids
American Christian writers
National Medal of Science laureates
University of Illinois Urbana-Champaign alumni
California Institute of Technology alumni
Recipients of the Gold Medal of the Royal Astronomical Society
Foreign Members of the Royal Society
1926 births
2010 deaths
Deaths from pancreatic cancer
Deaths from cancer in California
20th-century Christians
21st-century Christians
Members of the American Philosophical Society