James Hopwood Jeans
Encyclopedia
Sir James Hopwood Jeans OM
FRS MA DSc ScD LLD (11 September 1877 16 September 1946) was an English
physicist
, astronomer
and mathematician
.
, Lancashire
, Jeans was educated at Merchant Taylors' School, Northwood
, Wilson's Grammar School
, Camberwell
and Trinity College, Cambridge
, he finished Second Wrangler in the university in the Mathematical Tripos
of 1898. He taught at Cambridge, but went to Princeton University
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
, the theory of radiation
and stellar evolution
. His analysis of rotating bodies led him to conclude that Laplace
'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
. In 1928 Jeans was the first to conjecture a steady state cosmology based on a hypothesized continuous creation of matter in the universe. This theory was ruled out when the 1965 discovery of the cosmic microwave background 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
.
In 1939, the Journal of the British Astronomical Association
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
.
Jeans married twice, first to the American poet
Charlotte Tiffany Mitchell in 1907, then the Austria
n organ
ist and harpsichord
ist Suzanne Hock
(better known as Susi Jeans
) in 1935. He died in Dorking
, Surrey
.
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 but notably in Mathematics and Sciences.
hypothesis. They accepted the supposed near-collision between the sun and another star but believed that the material pulled out of the sun came out as a long spindle or cigar-shaped filament of solar gases. This gaseous filament later broke up into units which condensed to a molten and finally a solid stage, thus forming the planets. Astronomers have shown that a gaseous filament of this sort would not form solid bodies such as our planets; it would instead simply disappear in space. For this and many other reasons, this hypothesis is no longer acceptable to most scientists.
.
Sir James Jeans, in an interview published in The Observer
(London), when asked the question:
replied:
, is a critical radius of an interstellar cloud
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
, that solves for the critical mass a cloud must attain before being able to collapse.
Jeans also helped to discover the Rayleigh–Jeans law, which relates the energy density of blackbody radiation to the temperature of the emission source.
:
Other:
Order of Merit
The Order of Merit is a British dynastic order recognising distinguished service in the armed forces, science, art, literature, or for the promotion of culture...
FRS MA DSc ScD LLD (11 September 1877 16 September 1946) was an English
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
, astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
and mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
.
Background
Born in OrmskirkOrmskirk
Ormskirk is a market town in West Lancashire, England. It is situated north of Liverpool city centre, northwest of St Helens, southeast of Southport and southwest of Preston.-Geography and administration:...
, Lancashire
Lancashire
Lancashire is a non-metropolitan county of historic origin in the North West of England. It takes its name from the city of Lancaster, and is sometimes known as the County of Lancaster. Although Lancaster is still considered to be the county town, Lancashire County Council is based in Preston...
, Jeans was educated at Merchant Taylors' School, Northwood
Merchant Taylors' School, Northwood
Merchant Taylors' School is a British independent day school for boys, originally located in the City of London. Since 1933 it has been located at Sandy Lodge in the Three Rivers district of Hertfordshire ....
, Wilson's Grammar School
Wilson's School
Wilson's School is a boys' grammar school in Wallington, in the London Borough of Sutton, UK. Admission is based on performance in an entrance test with around 1,000 pupils being taught there....
, Camberwell
Camberwell
Camberwell is a district of south London, England, and forms part of the London Borough of Southwark. It is a built-up inner city district located southeast of Charing Cross. To the west it has a boundary with the London Borough of Lambeth.-Toponymy:...
and Trinity College, Cambridge
Trinity College, Cambridge
Trinity College is a constituent college of the University of Cambridge. Trinity has more members than any other college in Cambridge or Oxford, with around 700 undergraduates, 430 graduates, and over 170 Fellows...
, he finished Second Wrangler in the university in the Mathematical Tripos
Tripos
The University of Cambridge, England, divides the different kinds of honours bachelor's degree by Tripos , plural Triposes. The word has an obscure etymology, but may be traced to the three-legged stool candidates once used to sit on when taking oral examinations...
of 1898. He taught at Cambridge, but went to Princeton University
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
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 mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
, the theory of radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
and stellar evolution
Stellar evolution
Stellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. Depending on the mass of the star, this lifetime ranges from only a few million years to trillions of years .Stellar evolution is not studied by observing the life of a single...
. His analysis of rotating bodies led him to conclude that Laplace
Pierre-Simon Laplace
Pierre-Simon, marquis de Laplace was a French mathematician and astronomer whose work was pivotal to the development of mathematical astronomy and statistics. He summarized and extended the work of his predecessors in his five volume Mécanique Céleste...
'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
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...
. In 1928 Jeans was the first to conjecture a steady state cosmology based on a hypothesized continuous creation of matter in the universe. This theory was ruled out when the 1965 discovery of the cosmic microwave background was widely interpreted as the tell-tale signature of the Big Bang
Big Bang
The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
.
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
The Mysterious Universe
The Mysterious Universe, by the British astrophysicist Sir James Jeans, is a science book for lay persons, first published in 1930 by the Cambridge University Press....
. These books made Jeans fairly well known as an expositor of the revolutionary scientific discoveries of his day, especially in relativity
Theory of relativity
The theory of relativity, or simply relativity, encompasses two theories of Albert Einstein: special relativity and general relativity. However, the word relativity is sometimes used in reference to Galilean invariance....
and physical cosmology
Physical cosmology
Physical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...
.
In 1939, the Journal of the British Astronomical Association
Journal of the British Astronomical Association
-External links:* *...
reported that Jeans was going to stand as a candidate for parliament for the Cambridge University constituency
Cambridge University (UK Parliament constituency)
Cambridge University was a university constituency electing two members to the British House of Commons, from 1603 to 1950.-Boundaries, Electorate and Election Systems:...
. 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
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
and philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...
.
Jeans married twice, first to the American poet
Poet
A poet is a person who writes poetry. A poet's work can be literal, meaning that his work is derived from a specific event, or metaphorical, meaning that his work can take on many meanings and forms. Poets have existed since antiquity, in nearly all languages, and have produced works that vary...
Charlotte Tiffany Mitchell in 1907, then the Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
n organ
Organ (music)
The organ , is a keyboard instrument of one or more divisions, each played with its own keyboard operated either with the hands or with the feet. The organ is a relatively old musical instrument in the Western musical tradition, dating from the time of Ctesibius of Alexandria who is credited with...
ist and harpsichord
Harpsichord
A harpsichord is a musical instrument played by means of a keyboard. It produces sound by plucking a string when a key is pressed.In the narrow sense, "harpsichord" designates only the large wing-shaped instruments in which the strings are perpendicular to the keyboard...
ist Suzanne Hock
Susi Jeans
Susi Jeans , otherwise Lady Jeans, was an Austrian-born organist, musicologist and noted teacher. Born in Vienna, she was the oldest child of Oscar and Jektaterina Hock. Initially, she trained as a ballet dancer by the modernist teacher Gertrud Bodenwieser, but growing rather rapidly, switched to...
(better known as Susi Jeans
Susi Jeans
Susi Jeans , otherwise Lady Jeans, was an Austrian-born organist, musicologist and noted teacher. Born in Vienna, she was the oldest child of Oscar and Jektaterina Hock. Initially, she trained as a ballet dancer by the modernist teacher Gertrud Bodenwieser, but growing rather rapidly, switched to...
) in 1935. He died in Dorking
Dorking
Dorking is a historic market town at the foot of the North Downs approximately south of London, in Surrey, England.- History and development :...
, Surrey
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
.
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 but notably in Mathematics and Sciences.
Tidal Hypothesis
The Tidal or Gaseous Hypothesis of the earth involves an original sun that had a close encounter with a passing star. Known also as the tidal disruption or tidal filament hypothesis, this conception of how our solar system formed was proposed in 1918 by two British scientists, Sir James Jeans and Sir Harold Jeffreys. Jeans, an astronomer, and Jeffreys, a geophysicist, offered this proposal to counteract some of the objections that had been raised to the planetesimalPlanetesimal
Planetesimals are solid objects thought to exist in protoplanetary disks and in debris disks.A widely accepted theory of planet formation, the so-called planetesimal hypothesis of Viktor Safronov, states that planets form out of cosmic dust grains that collide and stick to form larger and larger...
hypothesis. They accepted the supposed near-collision between the sun and another star but believed that the material pulled out of the sun came out as a long spindle or cigar-shaped filament of solar gases. This gaseous filament later broke up into units which condensed to a molten and finally a solid stage, thus forming the planets. Astronomers have shown that a gaseous filament of this sort would not form solid bodies such as our planets; it would instead simply disappear in space. For this and many other reasons, this hypothesis is no longer acceptable to most scientists.
Idealism
For an overview see IdealismIdealism
In philosophy, idealism is the family of views which assert that reality, or reality as we can know it, is fundamentally mental, mentally constructed, or otherwise immaterial. Epistemologically, idealism manifests as a skepticism about the possibility of knowing any mind-independent thing...
.
The stream of knowledge is heading towards a non-mechanical reality; the Universe begins to look more like a great thought than like a great machine. Mind no longer appears to be an accidental intruder into the realm of matter... we ought rather hail it as the creator and governor of the realm of matter. Sir James Jeans "The mysterious universe" page 137.
Sir James Jeans, in an interview published in The Observer
The Observer
The Observer is a British newspaper, published on Sundays. In the same place on the political spectrum as its daily sister paper The Guardian, which acquired it in 1993, it takes a liberal or social democratic line on most issues. It is the world's oldest Sunday newspaper.-Origins:The first issue,...
(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?
replied:
I incline to the idealistic theory that consciousness is fundamental, and that the material universe is derivative from consciousness, not consciousness from the material universe... In general the universe seems to me to be nearer to a great thought than to a great machine. It may well be, it seems to me, that each individual consciousness ought to be compared to a brain-cell in a universal mind.
What remains is in any case very different from the full-blooded matter and the forbidding materialismMaterialismIn philosophy, the theory of materialism holds that the only thing that exists is matter; that all things are composed of material and all phenomena are the result of material interactions. In other words, matter is the only substance...
of the Victorian scientist. His objective and material universe is proved to consist of little more than constructs of our own minds. To this extent, then, modem physics has moved in the direction of philosophic idealism. Mind and matter, if not proved to be of similar nature, are at least found to be ingredients of one single system. There is no longer room for the kind of dualismDualismDualism denotes a state of two parts. The term 'dualism' was originally coined to denote co-eternal binary opposition, a meaning that is preserved in metaphysical and philosophical duality discourse but has been diluted in general or common usages. Dualism can refer to moral dualism, Dualism (from...
which has haunted philosophy since the days of Descartes. Sir James Jeans addressing the British Association in 1934.
Finite picture whose dimensions are a certain amount of space and a certain amount of time; the protons and electrons are the streaks of paint which define the picture against its space-time background. Traveling as far back in time as we can, brings us not to the creation of the picture, but to its edge; the creation of the picture lies as much outside the picture as the artist is outside his canvas. On this view, discussing the creation of the universe in terms of time and space is like trying to discover the artist and the action of painting, by going to the edge of the canvas. This brings us very near to those philosophical systems which regard the universe as a thought in the mind of its Creator, thereby reducing all discussion of material creation to futility. Sir James Jeans "The universe around us" page 317.
Major accomplishments
One of Jeans' major discoveries, named Jeans lengthJeans length
Jeans' length is the critical radius of a cloud where thermal energy, which causes the cloud to expand, is counteracted by gravity, which causes the cloud to collapse...
, is a critical radius of an interstellar cloud
Interstellar cloud
Interstellar cloud is the generic name given to 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. Depending on the density, size and temperature of a given cloud, the hydrogen in it...
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
Jeans instability
In physics, the Jeans instability causes the collapse of interstellar gas clouds and subsequent star formation. It occurs when the internal gas pressure is not strong enough to prevent gravitational collapse of a region filled with matter...
, that solves for the critical mass a cloud must attain before being able to collapse.
Jeans also helped to discover the Rayleigh–Jeans law, which relates the energy density of blackbody radiation to the temperature of the emission source.
Books
Available online from the Internet ArchiveInternet Archive
The Internet Archive is a non-profit digital library with the stated mission of "universal access to all knowledge". It offers permanent storage and access to collections of digitized materials, including websites, music, moving images, and nearly 3 million public domain books. The Internet Archive...
:
- 1904. The Dynamical Theory of Gases
- 1906. Theoretical Mechanics
- 1908. Mathematical Theory of Electricity and Magnetism
Other:
- 1929. The Universe Around UsThe Universe Around UsThe Universe Around Us is a science book written by English astrophysicist Sir James Jeans, first published in 1929 by the Syndics of the Cambridge University Press.-Editions:* First Edition...1929 ...Reprinted...1929, 1930...
- 1930. The Mysterious UniverseThe Mysterious UniverseThe Mysterious Universe, by the British astrophysicist Sir James Jeans, is a science book for lay persons, first published in 1930 by the Cambridge University Press....
- 1931. The Stars in Their Courses
- 1933. The New Background of Science
- 1937. Science and Music
- 1942. Physics and Philosophy
Awards and honours
- Fellow of the Royal Society in May, 1906
- Bakerian LectureBakerian LectureThe Bakerian Lecture is a prize lecture of the Royal Society, a lecture on physical sciences.In 1775 Henry Baker left £100 for a spoken lecture by a Fellow on such part of natural history or experimental philosophy as the Society shall determine....
to Royal SocietyRoyal SocietyThe Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1917. - Royal MedalRoyal MedalThe Royal Medal, also known as The Queen's Medal, is a silver-gilt medal awarded each year by the Royal Society, two for "the most important contributions to the advancement of natural knowledge" and one for "distinguished contributions in the applied sciences" made within the Commonwealth of...
of the Royal SocietyRoyal SocietyThe Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1919. - Hopkins Prize of the Cambridge Philosophical SocietyCambridge Philosophical SocietyThe Cambridge Philosophical Society is a scientific society at 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 theology and medicine...
1921–1924. - Gold Medal of the Royal Astronomical SocietyGold Medal of the Royal Astronomical Society-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
in 1922. - He was knightKnightA knight was a member of a class of lower nobility in the High Middle Ages.By the Late Middle Ages, the rank had become associated with the ideals of chivalry, a code of conduct for the perfect courtly Christian warrior....
ed in 1928. - Franklin MedalFranklin MedalThe Franklin Medal was a science and engineering award presented by the Franklin Institute, of Philadelphia, PA, USA.-Laureates:*1915 - Thomas Alva Edison *1915 - Heike Kamerlingh Onnes *1916 - John J...
of the Franklin InstituteFranklin InstituteThe Franklin Institute is a museum in Philadelphia, Pennsylvania, and one of the oldest centers of science education and development in the United States, dating to 1824. The Institute also houses the Benjamin Franklin National Memorial.-History:On February 5, 1824, Samuel Vaughn Merrick and...
in 1931. - Mukerjee Medal of the Indian Association for the Cultivation of ScienceIndian Association for the Cultivation of ScienceThe Indian Association for the Cultivation of Science, established in July 1876 at 210 Bowbazar street, Calcutta, is a national institution for higher learning whose primary purpose is to foster high quality fundamental research in frontier disciplines of the basic sciences. Founded by Dr. Mahendra...
in 1937. - President of the 25th session of the Indian Science Congress in 1938.
- Calcutta Medal of the Indian Science Congress AssociationIndian Science Congress AssociationIndian Science Congress Association is a premier scientific organisation of India,started in the year 1914, with Headquarters at Kolkata.. It meets annually in the first week of January every year.-Introduction:...
in 1938. - Member of the Order of MeritOrder of MeritThe Order of Merit is a British dynastic order recognising distinguished service in the armed forces, science, art, literature, or for the promotion of culture...
in 1939.
- The crater JeansJeans (lunar crater)Jeans is a lunar crater along the southeastern limb of the Moon. The majority of this formation lies on the far side with respect to the Earth, but favorable librations can bring the entire crater into view...
on the MoonMoonThe Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
is named after him, as is the crater Jeans on MarsMarsMars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
. - The String Quartet No.7 by Robert SimpsonRobert Simpson (composer)Robert Simpson was an English composer and long-serving BBC producer and broadcaster.He is best known for his orchestral and chamber music , and for his writings on the music of Beethoven, Bruckner, Nielsen and Sibelius. He studied composition under Herbert Howells...
was written in tribute to him on the centenary of his birth, 1977.
External links
- MacTutor (St. Andrews Univ.): More biographical information., including photos
- Britannica article includes photo