Sir James Hopwood Jeans
(11 September 187716 September 1946
) was an English
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate cau ...
,
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, moons, comets and galaxies – in either ...
and
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
.
Early life
Born in
Ormskirk
Ormskirk is a market town in the West Lancashire district of Lancashire, England, north of Liverpool, northwest of St Helens, southeast of Southport and southwest of Preston. Ormskirk is known for its gingerbread.
Geography and administr ...
,
Lancashire
Lancashire ( , ; abbreviated Lancs) is the name of a historic county, ceremonial county, and non-metropolitan county in North West England. The boundaries of these three areas differ significantly.
The non-metropolitan county of Lancash ...
, the son of
William Tulloch Jeans
William Tulloch Jeans (1848–1907) was a British parliamentary journalist and author.
Career
Jeans was parliamentary correspondent for ''The Globe'', and was widely known for and consulted on his knowledge of parliamentary principle.
In their 1 ...
, a parliamentary correspondent and author. Jeans was educated at
Merchant Taylors' School,
Wilson's Grammar School
Wilson's School is a state boys' grammar school with academy status in the London Borough of Sutton, England.
It was founded as Wilson's Grammar School in Camberwell in 1615, making it one of the country's oldest state schools. The school move ...
,
Camberwell and
Trinity College, Cambridge
Trinity College is a constituent college of the University of Cambridge. Founded in 1546 by King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any college at either Cambridge or Oxford. ...
.
As a gifted student, Jeans was counselled to take an aggressive approach to the
Cambridge Mathematical Tripos
The Mathematical Tripos is the mathematics course that is taught in the Faculty of Mathematics at the University of Cambridge. It is the oldest Tripos examined at the University.
Origin
In its classical nineteenth-century form, the tripos was ...
competition:
Career
Jeans was elected
Fellow
A fellow is a concept whose exact meaning depends on context.
In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements.
Within the context of higher education ...
of Trinity College in October 1901,
and taught at Cambridge, but went to
Princeton University
Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...
in 1904 as a professor of applied mathematics. He returned to Cambridge in 1910.
He made important contributions in many areas of physics, including
quantum theory
Quantum theory may refer to:
Science
*Quantum mechanics, a major field of physics
*Old quantum theory, predating modern quantum mechanics
* Quantum field theory, an area of quantum mechanics that includes:
** Quantum electrodynamics
** Quantum ...
, the theory of
radiation and
stellar evolution. His analysis of rotating bodies led him to conclude that
Pierre-Simon Laplace
Pierre-Simon, marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French scholar and polymath whose work was important to the development of engineering, mathematics, statistics, physics, astronomy, and philosophy. He summarized ...
's theory that the solar system formed from a single cloud of gas was incorrect, proposing instead that the planets condensed from material drawn out of the sun by a hypothetical catastrophic near-collision with a passing star. This theory is not accepted today.
Jeans, along with
Arthur Eddington, is a founder of British
cosmology
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 ...
. In 1928, Jeans was the first to conjecture a
steady state cosmology based on a hypothesized continuous creation of matter in the universe. In his book ''Astronomy and Cosmology'' (1928) he stated: "The type of conjecture which presents itself, somewhat insistently, is that the centers of the nebulae are of the nature 'singular points' at which matter is poured into our universe from some other, and entirely extraneous spatial dimension, so that, to a denizen of our universe, they appear as points at which matter is being continually created."
This theory fell out of favour when the 1965 discovery of the
cosmic microwave background
In Big Bang cosmology the cosmic microwave background (CMB, CMBR) is electromagnetic radiation that is a remnant from an early stage of the universe, also known as "relic radiation". The CMB is faint cosmic background radiation filling all spac ...
was widely interpreted as the tell-tale signature of the
Big Bang.
His scientific reputation is grounded in the monographs ''The Dynamical Theory of Gases'' (1904), ''Theoretical Mechanics'' (1906), and ''Mathematical Theory of Electricity and Magnetism'' (1908). After retiring in 1929, he wrote a number of books for the lay public, including ''The Stars in Their Courses'' (1931), ''
The Universe Around Us'', ''Through Space and Time'' (1934), ''The New Background of Science'' (1933), and ''
The Mysterious Universe.'' These books made Jeans fairly well known as an expositor of the revolutionary scientific discoveries of his day, especially in
relativity and
physical cosmology
Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of f ...
.
In 1939, the
Journal of the British Astronomical Association
The ''Journal of the British Astronomical Association'' is a peer-reviewed scientific journal of astronomy published by the British Astronomical Association since October 1890. It is currently edited by Philip Jennings and publishes original re ...
reported that Jeans was going to stand as a candidate for parliament for the
Cambridge University constituency. The election, expected to take place in 1939 or 1940, did not take place until 1945, and without his involvement.
He also wrote the book ''Physics and Philosophy'' (1943) where he explores the different views on reality from two different perspectives: science and philosophy. On his religious views, Jeans was an agnostic
Freemason.
Personal life
Jeans married twice, first to the American poet
Charlotte Tiffany Mitchell in 1907, who died,
and then to the Austrian
organist and
harpsichordist Suzanne Hock (better known as
Susi Jeans
Susi may refer to:
* 933 Susi, a minor planet orbiting the Sun
*Susi Air, an Indonesian airline
* Sydney University Stellar Interferometer, an optical interferometer in Sydney, Australia
People Given name
* Susi Erdmann (born 1968), German luger ...
) in 1935. Susi and Jeans had three children: George, Christopher, and Catherine.
At
Merchant Taylors' School there is a James Jeans Academic Scholarship for the candidate in the entrance exams who displays outstanding results across the spectrum of subjects, notably in mathematics and the sciences.
Major accomplishments
One of Jeans' major discoveries, named
Jeans length, is a critical radius of an
interstellar cloud
An interstellar cloud is generally an accumulation of gas, plasma, and dust in our and other galaxies. Put differently, an interstellar cloud is a denser-than-average region of the interstellar medium, the matter and radiation that exists in ...
in space. It depends on the temperature, and density of the cloud, and the mass of the particles composing the cloud. A cloud that is smaller than its Jeans length will not have sufficient gravity to overcome the repulsive gas pressure forces and condense to form a star, whereas a cloud that is larger than its Jeans length will collapse.
:
Jeans came up with another version of this equation, called Jeans mass or
Jeans instability
In stellar physics, the Jeans instability causes the collapse of interstellar gas clouds and subsequent star formation, named after James Jeans. It occurs when the internal gas pressure is not strong enough to prevent gravitational collapse of ...
, that solves for the critical mass a cloud must attain before being able to collapse.
Jeans also helped to discover the
Rayleigh–Jeans law
In physics, the Rayleigh–Jeans law is an approximation to the spectral radiance of electromagnetic radiation as a function of wavelength from a black body at a given temperature through classical arguments. For wavelength λ, it is:
B_ (T) = \ ...
, which relates the energy density of
black-body radiation to the temperature of the emission source.
:
Jeans is also credited with calculating the rate of
atmospheric escape
Atmospheric escape is the loss of planetary atmospheric gases to outer space. A number of different mechanisms can be responsible for atmospheric escape; these processes can be divided into thermal escape, non-thermal (or suprathermal) escape, and ...
from a planet due to kinetic energy of the gas molecules, a process known as Jeans Escape.
Idealism
In an interview published in ''
The Observer
''The Observer'' is a British newspaper published on Sundays. It is a sister paper to ''The Guardian'' and '' The Guardian Weekly'', whose parent company Guardian Media Group Limited acquired it in 1993. First published in 1791, it is the ...
'' (London), when asked the question "Do you believe that life on this planet is the result of some sort of accident, or do you believe that it is a part of some great scheme?", he replied:
Awards and honours
*
Fellow of the Royal Society
Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the judges of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural knowledge, including mathemat ...
in May 1906
*
Bakerian Lecture to
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 ...
in 1917.
*
Royal Medal 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 ...
in 1919.
*
Hopkins Prize
Hopkins is an English, Welsh and Irish patronymic surname. The English name means "son of Hob". ''Hob'' was a diminutive of ''Robert'', itself deriving from the Germanic warrior name ''Hrod-berht'', translated as "renowned-fame". The Robert s ...
of the
Cambridge Philosophical Society
The Cambridge Philosophical Society (CPS) is a scientific society at the University of Cambridge. It was founded in 1819. The name derives from the medieval use of the word philosophy to denote any research undertaken outside the fields of la ...
1921–1924.
*
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 ...
in 1922.
* He was
knight
A knight is a person granted an honorary title of knighthood by a head of state (including the Pope) or representative for service to the monarch, the church or the country, especially in a military capacity. Knighthood finds origins in the Gr ...
ed in 1928.
*
Franklin Medal
The Franklin Medal was a science award presented from 1915 until 1997 by the Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the Am ...
of the
Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...
in 1931.
* In 1933 Jeans was invited to deliver the
Royal Institution Christmas Lecture on ''Through Space and Time''.
* Mukerjee Medal of the
Indian Association for the Cultivation of Science
Indian Association for the Cultivation of Science (IACS) is a public, deemed, research university for higher education and research in basic sciences under the Department of Science & Technology, Government of India, situated at the heart of ...
in 1937.
* President of the 25th session of the
Indian Science Congress
Indian Science Congress Association(ISCA) is a premier scientific organisation of India with headquarters at Kolkata, West Bengal. The association started in the year 1914 in Kolkata and it meets annually in the first week of January. It has a ...
in 1938.
* Calcutta Medal of the
Indian Science Congress Association in 1938.
* Lorimer Medal of the
Astronomical Society of Edinburgh in 1938
for which he gave the Lorimer Lecture: ''The Depths of Space''.
* Member of the
Order of Merit in 1939.
* The crater
Jeans on the Moon is named after him, as is the crater
Jeans on Mars.
* The String Quartet No.7 by
Robert Simpson was written in tribute to him on the centenary of his birth, 1977.
Bibliography
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References
Sources
*
* (quoting Jeans, The Mysterious Universe, p. 134).
*
*
External links
*
Britannica articleincludes photo
*
;Works of Jeans available online from the
Internet Archive
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...
*1904.
The Dynamical Theory of Gases'
*1906.
Theoretical Mechanics'
*1908.
Mathematical Theory of Electricity and Magnetism'
*1947.
The Growth of Physical Science'
{{DEFAULTSORT:Jeans, James Hopwood
1877 births
1946 deaths
20th-century English mathematicians
Alumni of Trinity College, Cambridge
British agnostics
20th-century British astronomers
British physicists
English agnostics
English Freemasons
English physicists
Fellows of the Royal Society
Fellows of Trinity College, Cambridge
Fluid dynamicists
Idealists
Knights Bachelor
Members of the Order of Merit
Metaphysicians
Ontologists
People educated at Merchant Taylors' School, Northwood
People educated at Wilson's School, Wallington
People from Ormskirk
Philosophers of mathematics
Philosophers of mind
Philosophers of science
Presidents of the British Science Association
Presidents of the Royal Astronomical Society
Princeton University faculty
Recipients of the Gold Medal of the Royal Astronomical Society
Royal Medal winners
Second Wranglers