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From Wikipedia, the free encyclopedia

Sir

James Jeans

Born
James Hopwood Jeans

(1877-09-11)11 September 1877
Died16 September 1946(1946-09-16) (aged 69)
Dorking, Surrey, England
Alma materMerchant Taylors' School; Cambridge University
Known forJeans equations
Jeans escape
Jeans instability
Jeans mass
Jeans length
Jeans's theorem
Rayleigh–Jeans law
Method of image charges
Tidal hypothesis
AwardsSmith's Prize (1901)
Adams Prize (1917)
Royal Medal (1919)
Scientific career
FieldsAstronomy, mathematics, physics
InstitutionsTrinity College, Cambridge; Princeton University
Notable studentsRonald Fisher

Sir James Hopwood Jeans OM FRS[1] (11 September 1877 – 16 September 1946[2]) was an English physicist, astronomer and mathematician.

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Transcription

Early life

Born in Ormskirk, Lancashire, the son of William Tulloch Jeans, a parliamentary correspondent and author. Jeans was educated at Merchant Taylors' School, Wilson's Grammar School,[3][4] Camberwell and Trinity College, Cambridge.[5] As a gifted student, Jeans was counselled to take an aggressive approach to the Cambridge Mathematical Tripos competition:[6]

Early in the Michaelmas term of 1896, Walker sent for Jeans and Hardy and advised them to take Part I of the Mathematical Tripos in two years. He told them that he could not guarantee that they would come out higher than fifteenth in the list of wranglers, but he understood that they would never regret it. They accepted his advice, and went to R. R. Webb, the most famous private coach of the period ... At the end of his first year, [Jeans] told Walker that he had quarrelled with Webb, his coach. Walker accordingly took Jeans himself, and the result was a triumph: ... Jeans was bracketed second wrangler with J. F. Cameron ... [and] R.W.H.T. Hudson was Senior Wrangler and G. H. Hardy fourth wrangler.

Career

Jeans was elected Fellow of Trinity College in October 1901,[7][8] and 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 Pierre-Simon 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.[9] In his book Astronomy and Cosmogony (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."[10] This theory fell out of favour 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. On his religious views, Jeans was an agnostic Freemason.[11][12]

Personal life

Jeans married twice, first to the American poet Charlotte Tiffany Mitchell in 1907, who died,[13] and then to the Austrian organist and harpsichordist Suzanne Hock (better known as Susi Jeans) in 1935. Susi and Jeans had three children: George, Christopher, and Catherine.[14]

Death

Jeans died in 1947 with the presence of his wife and Joy Adamson, who suggested to the widow to create a death mask of Jeans. It is now held by the Royal Society.[15][16]

Major accomplishments

One of Jeans' major discoveries, named Jeans length, 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 black-body radiation to the temperature of the emission source.

Jeans is also credited with calculating the rate of atmospheric escape from a planet due to kinetic energy of the gas molecules, a process known as Jeans escape.

Idealism

Jeans espoused a philosophy of science rooted in the metaphysical doctrine of idealism and opposed to materialism in his speaking engagements and books. His popular science publications first advanced these ideas in 1929's The Universe Around Us when he likened "discussing the creation of the universe in terms of time and space," to, "trying to discover the artist and the action of painting, by going to the edge of the canvas." But he turned to this idea as the primary subject of his best-selling[17] 1930 book, The Mysterious Universe, where he asserted that a picture of the universe as a "non-mechanical reality" was emerging from the science of the day.

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.

— James Jeans, The Mysterious Universe, [18]

In a 1931 interview published in The Observer, Jeans was asked if he believed that life was an accident or if it was, "part of some great scheme." He said that he favored, "the idealistic theory that consciousness is fundamental, and that the material universe is derivative from consciousness," going on to suggest that, "each individual consciousness ought to be compared to a brain-cell in a universal mind."[19]

In his 1934 address to the British Association for the Advancement of Science meeting in Aberdeen as the Association's president, Jeans spoke specifically to the work of Descartes and its relevance to the modern philosophy of science. He argued that, "There is no longer room for the kind of dualism which has haunted philosophy since the days of Descartes."[20]

When Daniel Helsing reviewed The Mysterious Universe for Physics Today in 2020, he summarized the philosophical conclusions of the book, "Jeans argues that we must give up science’s long-cherished materialistic and mechanical worldview, which posits that nature operates like a machine and consists solely of material particles interacting with each other." His evaluation of Jeans contrasted these philosophical views with modern science communicators such as Neil deGrasse Tyson and Sean Carroll who he suggested, "would likely take issue with Jeans’s idealism."[17]

Awards and honours

Bibliography

The Astronmical Horizon https://www.amazon.co.uk/dp/B000NIS57O?ref=myi_title_dp- The Philip Maurice Deneke Lecture 1944 - Published Oxford University Press 1945

References

  1. ^ Milne, E. A. (1947). "James Hopwood Jeans. 1877–1946". Obituary Notices of Fellows of the Royal Society. 5 (15): 573–589. doi:10.1098/rsbm.1947.0019. S2CID 162237490.
  2. ^ "England & Wales deaths 1837-2007 Transcription". Findmypast. Retrieved 27 June 2016. SEP 1946 5g 607 SURREY SE
  3. ^ Milne 2013, p. 1.
  4. ^ Allport & Friskney 1987, p. 234.
  5. ^ "Jeans, James Hopwood (JNS896JH)". A Cambridge Alumni Database. University of Cambridge.
  6. ^ Milne 2013, pp. 4–5.
  7. ^ "University intelligence – Cambridge". The Times. No. 36583. London. 11 October 1901. p. 4.
  8. ^ "University Intelligence – The New Trinity Fellows Cambridge". London Daily News. 11 October 1901. p. 3 col E. Retrieved 27 June 2016 – via British Newspaper Archive.
  9. ^ Jeans 1928, p. 360.
  10. ^ Reynosa, Peter (16 March 2016). "Why Isn't Edward P. Tryon A World-famous Physicist?". The Huffington Post. Retrieved 27 June 2016.
  11. ^ Teilhard De Chardin 2004, p. 212.
  12. ^ Bell 1986, p. xvii.
  13. ^ O'Connor, John J.; Robertson, Edmund F., "James Hopwood Jeans", MacTutor History of Mathematics Archive, University of St Andrews
  14. ^ Meadows, A. J. "Jeans, Sir James Hopwood". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/34164. (Subscription or UK public library membership required.)
  15. ^ "Search Results". catalogues.royalsociety.org. Retrieved 8 August 2023.
  16. ^ "Face to Face". Brady Haran. 30 September 2015. Retrieved 8 August 2023.
  17. ^ a b Helsing, Daniel (November 2020). "James Jeans and The Mysterious Universe: The controversial best seller heralded the end of an era in science popularizations". Physics Today. Vol. 73, no. 11. American Institute of Physics. Retrieved 20 September 2023.
  18. ^ Jeans 1944, p. 137.
  19. ^ Purucker, Gottfried (1931). Questions We All Ask: A Series of Lectures Delivered in the Temple of Peace, Point Loma, California, from June 29, 1930, to October 26, 1930 (PDF). United States: Theosophical University Press. p. 223. ISBN 0766139565. Retrieved 20 September 2023.
  20. ^ Jeans 1981, p. 216.
  21. ^ "Lorimer Medal - Astronomical Society of Edinburgh".

Sources

External links

Works of Jeans available online from the Internet Archive
This page was last edited on 10 March 2024, at 10:30
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