Gerald Maurice Clemence (16 August 1908 – 22 November 1974) 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 ...
. Inspired by the life and work of
Simon Newcomb
Simon Newcomb (March 12, 1835 – July 11, 1909) was a Canadian–American astronomer, applied mathematician, and autodidactic polymath. He served as Professor of Mathematics in the United States Navy and at Johns Hopkins University. Born in Nov ...
, his career paralleled the huge advances in astronomy brought about by the advent of the
electronic computer
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These progra ...
. Clemence did much to revive the prestige of the
U.S. Nautical Almanac Office.
[Duncombe (2001)]
Early life
Born on a farm near
Greenville, Rhode Island
Greenville is a village and census-designated place (CDP) in the New England town, town of Smithfield, Rhode Island, Smithfield in Providence County, Rhode Island, Providence County, Rhode Island, United States. The population was 8,658 at the 2010 ...
, Gerald's parents were Richard R. Clemence and his wife, Lora, ''née'' Oatley. Much of his elementary education was at home with his mother, herself a schoolteacher, and he learned about astronomy from his own enthusiastic reading. Clemence attended
Brown University
Brown University is a private research university in Providence, Rhode Island. Brown is the seventh-oldest institution of higher education in the United States, founded in 1764 as the College in the English Colony of Rhode Island and Providenc ...
and read
mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
, achieving a
PhB degree in 1930. In his own words, "as a recreation", he took the
civil service examination
Civil service examinations are examinations implemented in various countries for recruitment and admission to the civil service. They are intended as a method to achieve an effective, rational public administration on a merit system for recruiti ...
for the job description "astronomer" and finished first out of fifty candidates, winning appointment at the
United States Naval Observatory
United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...
. Taking up the post, he married Edith Melvina Vail, a
nurse
Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life. Nurses may be differentiated from other health c ...
, in 1929.
Mercury and Mars
After initial work in the Time Service Department, alongside
William Markowitz
William Markowitz (February 8, 1907 in Melč, Austrian Silesia – October 10, 1998 in Pompano Beach, Florida) was an American astronomer, principally known for his work on the standardization of time.
His mother was visiting Melč near Ví ...
, Clemence was assigned to work under
H. R. Morgan.
George William Hill
George William Hill (March 3, 1838 – April 16, 1914) was an American astronomer and mathematician. Working independently and largely in isolation from the wider scientific community, he made major contributions to celestial mechanics and t ...
had computed the
orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...
s of
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...
and
Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...
in the nineteenth century and Newcomb had completed the work for the other
planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
s of the
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
. However, there was now almost fifty years of new observational data and Clemence set to recalculate the
orbital elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same ...
of
Mercury
Mercury commonly refers to:
* Mercury (planet), the nearest planet to the Sun
* Mercury (element), a metallic chemical element with the symbol Hg
* Mercury (mythology), a Roman god
Mercury or The Mercury may also refer to:
Companies
* Merc ...
to provide more
accurate
Accuracy and precision are two measures of '' observational error''.
''Accuracy'' is how close a given set of measurements ( observations or readings) are to their ''true value'', while ''precision'' is how close the measurements are to each ot ...
predictions. His results, published in 1943, clearly showed the
perihelion precession of Mercury
Tests of general relativity serve to establish observational evidence for the theory of general relativity. The first three tests, proposed by Albert Einstein in 1915, concerned the "anomalous" precession of the perihelion of Mercury, the bendin ...
predicted by the
general theory of relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the differential geometry, geometric scientific theory, theory of gravitation published by Albert Einstein in 1915 and is the current descr ...
.
Clemence identified systematic errors in the predictions of
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
' path. The
residuals showed a marked
periodicity
Periodicity or periodic may refer to:
Mathematics
* Bott periodicity theorem, addresses Bott periodicity: a modulo-8 recurrence relation in the homotopy groups of classical groups
* Periodic function, a function whose output contains values tha ...
and Clemence concluded that the
Fourier series
A Fourier series () is a summation of harmonically related sinusoidal functions, also known as components or harmonics. The result of the summation is a periodic function whose functional form is determined by the choices of cycle length (or ''p ...
on which the predictions were based was wrong. Clemence set out to derive a new series from scratch using the methods detailed by Hill and
Peter Andreas Hansen
Peter Andreas Hansen (born 8 December 1795, Tønder, Schleswig, Denmark; died 28 March 1874, Gotha, Thuringia, Germany) was a Danish-born German astronomer.
Biography
The son of a goldsmith, Hansen learned the trade of a watchmaker at Flensburg, ...
in the nineteenth century. The calculations were carried out with "a lead pencil, large sheets of computing paper,
nda hand-operated
''Millionaire'' desk calculator".
Though electronic calculators were available towards the end of the project, the calculations took twelve years.
Nautical Almanac Office
Wallace John Eckert
Wallace John Eckert (June 19, 1902 – August 24, 1971) was an American astronomer, who directed the Thomas J. Watson Astronomical Computing Bureau at Columbia University which evolved into the research division of IBM.
Life
Wallace John Eckert ...
was appointed as director of the Nautical Almanac Office in 1940 and immediately imported his enthusiasm for using
punched card
A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...
machines for scientific calculation. Clemence was an early senior appointment to the new regime and soon saw the potential of electronic computation, using it initially on his Mars work but increasingly on the military work whose priority escalated following the entry of the U.S. into
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
.
Clemence was appointed assistant director in 1942 and was joined on the staff by
Paul Herget
Paul Herget (January 30, 1908 – August 27, 1981) was an American astronomer and director of the Cincinnati Observatory, who established the Minor Planet Center after World War II.
Career
Herget taught astronomy at the University of Cincinna ...
.
The pair worked on calculating
mathematical tables and developed the
optimum-interval technique to construct tables calculated at non-constant intervals and for which
linear interpolation
In mathematics, linear interpolation is a method of curve fitting using linear polynomials to construct new data points within the range of a discrete set of known data points.
Linear interpolation between two known points
If the two known poin ...
was everywhere legitimate.
In 1945, Eckert left for the
IBM-sponsored computing laboratory at
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
and Herget became director of the
Cincinnati Observatory
The Cincinnati Observatory is located in Cincinnati, Ohio, Cincinnati, Ohio (United States) on top of Mount Lookout, Ohio, Mount Lookout. It consists of two observatory buildings housing an 11-inch (28 cm) and 16 inch (41 cm) apertu ...
. Clemence was promoted to director of the Nautical Almanac Office, the post once held by his role-model Newcomb, and proved an able and energetic administrator.
Research collaboration
In 1947, there began an intense period of cooperative research on
celestial mechanics
Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to ...
between Clemence's office, Eckert's group at Columbia and
Yale University Observatory
The Yale University Observatory, also known as the Leitner Family Observatory and Planetarium, is an astronomy, astronomical observatory owned and operated by Yale University, and maintained for student use. It is located in Farnham Memorial Garden ...
, under the direction of
Dirk Brouwer
Dirk Brouwer (; September 1, 1902 – January 31, 1966) was a Dutch-American astronomer.
He received his PhD in 1927 at Leiden University under Willem de Sitter and then went to Yale University. From 1941 until 1966 he was editor of the ''Astr ...
, a former collaborator of Eckert's on punched cards.
Later career
In 1958, Clemence was appointed first scientific director of the
U.S. Naval Observatory
United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...
, a post he again addressed with enthusiasm and vigour. His own
original research
Research is "creativity, creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular att ...
necessarily took a lower profile but he continued to publish on
relativity,
astronomical constant An astronomical constant is any of several physical constants used in astronomy. Formal sets of constants, along with recommended values, have been defined by the International Astronomical Union (IAU) several times: in 1964Resolution No.4 of thXII ...
s and
time measurement
Time is the continued sequence of existence and event (philosophy), events that occurs in an apparently irreversible process, irreversible succession from the past, through the present, into the future. It is a component quantity of various me ...
, as well as collaborating on two text books.
[Woolard & Clemence (1966)]
However, Clemence's passion for research ultimately led him to relinquish his managerial roles in 1962, and, in 1963 Brouwer found him a post at Yale. Here, Clemence continued his work on the
perturbation theory
In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle ...
of the
Earth's orbit
Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi) in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes days (1 sidereal year), during which time Earth ...
but it was interrupted, never to be completed, in 1966 when Brouwer's death demanded that Clemence take over the administration of the department.
He died in
Providence, Rhode Island
Providence is the capital and most populous city of the U.S. state of Rhode Island. One of the oldest cities in New England, it was founded in 1636 by Roger Williams, a Reformed Baptist theologian and religious exile from the Massachusetts Bay ...
on November 22, 1974, after an illness of several months.
Personality
Clemence was reserved and dignified, conservative in manner and appearance. In writing he was concise and accurate. He was sincere and forthright with a code of ethics inherited from his parents. He was a family man, father of two sons, and always maintained contact with his three brothers and his sister. He was a keen, and self-taught,
musician
A musician is a person who composes, conducts, or performs music. According to the United States Employment Service, "musician" is a general term used to designate one who follows music as a profession. Musicians include songwriters who wri ...
, accomplished at
violin
The violin, sometimes known as a ''fiddle'', is a wooden chordophone (string instrument) in the violin family. Most violins have a hollow wooden body. It is the smallest and thus highest-pitched instrument (soprano) in the family in regular ...
,
piano
The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a keyboa ...
and
organ. He was also a keen
railfan
A railfan, rail buff or train buff (American English), railway enthusiast, railway buff or trainspotter (Australian/British English), or ferroequinologist is a person who is recreationally interested in trains and rail transport systems.
Rail ...
.
Offices, awards and honors
* Fellow of the
Royal Astronomical Society
(Whatever shines should be observed)
, predecessor =
, successor =
, formation =
, founder =
, extinction =
, merger =
, merged =
, type = NGO ...
(
UK), (1946);
* Honorary member of the
Royal Astronomical Society of Canada
Royal may refer to:
People
* Royal (name), a list of people with either the surname or given name
* A member of a royal family
Places United States
* Royal, Arkansas, an unincorporated community
* Royal, Illinois, a village
* Royal, Iowa, ...
, (1946);
* 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 ...
, (1952);
* Fellow of the
American Academy of Arts and Sciences
The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...
, (1955);
* President
American Astronomical Society
The American Astronomical Society (AAS, sometimes spoken as "double-A-S") is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC. The primary objective of the AAS is to promote the adv ...
, (1958–1960);
*
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 ...
, (1965);
* Editor of the ''
Astronomical Journal
''The Astronomical Journal'' (often abbreviated ''AJ'' in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society (AAS) and currently published by IOP Publishing. It is one of the p ...
'', (1969–1974);
*
James Craig Watson Medal 400px, James Craig Watson Medal
The James Craig Watson Medal was established by the bequest of James Craig Watson, an astronomer the University of Michigan between 1863 and 1879, and is awarded every 1-4 years by the U.S. National Academy of Scienc ...
of the National Academy of Sciences, (1975);
* The main-belt asteroid
1919 Clemence was named in his memory.
References
Bibliography
*
*
*
*
External links
*
*
*
*
National Academy of Sciences Biographical Memoir
{{DEFAULTSORT:Clemence, Gerald Maurice
1908 births
1974 deaths
American astronomers
Recipients of the Gold Medal of the Royal Astronomical Society
Members of the United States National Academy of Sciences
The Astronomical Journal editors