View source for Edward Arthur Milne

{{Short description|British astrophysicist and mathematician}}
{{Other people|Edward Milne}}
{{redirect|Arthur Milne|the Scottish footballer|Arthur Milne (footballer)}}
{{EngvarB|date=August 2014}}
{{Use dmy dates|date=August 2014}}
{{Infobox scientist
|name              = Arthur Milne
|image             = Edward Arthur Milne-(1917).jpg
|caption           = 
|birth_date        = {{birth date|df=yes|1896|02|14}}
|birth_place       = [[Kingston upon Hull]], Yorkshire, England
|death_date        = {{death date and age|df=yes|1950|09|21|1896|02|14}}
|death_place       = [[Dublin]], Ireland
|residence         = 
|citizenship       = 
|nationality       = 
|field             = 
|work_institutions = [[Victoria University of Manchester]] <br/> [[University of Oxford]]
|alma_mater        = [[Trinity College, Cambridge]]
|doctoral_advisor  = 
|doctoral_students = [[Thomas Cowling]]
|known_for         = [[Milne model]]<br>[[Degenerate matter|Degenerate stars]]
|influences        = 
|influenced        = 
|prizes            = 
|religion          = 
|signature         =
}}
'''Edward Arthur Milne''' [[Royal Society|FRS]]<ref name="frs">{{Cite journal | last1 = McCrea | first1 = W. H. | author-link = William McCrea (astronomer)| title = Edward Arthur Milne. 1896–1950 | doi = 10.1098/rsbm.1951.0010 | journal = [[Obituary Notices of Fellows of the Royal Society]] | volume = 7 | issue = 20 | pages = 420–426 | year = 1951 | jstor = 769028| s2cid = 192057220 | doi-access = free }}</ref> ({{IPAc-en|m|ɪ|l|n}}; 14 February 1896 – 21 September 1950) was a British [[astrophysicist]] and mathematician.<ref>{{MacTutor Biography|id=Milne}}</ref><ref name="obit_mnras1">{{cite journal
  | last = McCrea
  | first = W. H.
  | author-link = William McCrea (astronomer)
  | title = Edward Arthur Milne
  | journal = [[Monthly Notices of the Royal Astronomical Society]]
  | volume = 111
  | number = 2
  | pages = 160–170
  | date = 1951
  | bibcode = 1951MNRAS.111R.160.
  | doi=10.1093/mnras/111.2.160a
| doi-access = free
  }}</ref><ref name="obit_mnras2">{{cite journal
  | last = Plaskett
  | first = H. H.
  | author-link = Harry Hemley Plaskett
  | title = Edward Arthur Milne
  | journal = [[Monthly Notices of the Royal Astronomical Society]]
  | volume = 111
  | number = 2
  | pages = 170–172
  | date = 1951
  | bibcode = 1951MNRAS.111R.160.
  | doi=10.1093/mnras/111.2.160a
| doi-access = free
  }}</ref><ref name="obit_obs">{{cite journal
  | last = McCrea
  | first = W. H.
  | author-link = William McCrea (astronomer)
  | title = Edward Arthur Milne
  | journal = [[The Observatory (journal)|The Observatory]]
  | volume = 70
  | issue = 859
  | pages = 225–232
  | date = 1950
  | bibcode = 1950Obs....70..225M
  | url = http://articles.adsabs.harvard.edu/full/1950Obs....70..225M
  | access-date = 10 June 2016
}}</ref><ref name="obit_jbaa">{{cite journal
  | title = Obituary: Edward Arthur Milne
  | journal = [[Journal of the British Astronomical Association]]
  | volume = 61
  | number = 3
  | pages = 75–77
  | date = 1951
  | bibcode = 1951JBAA...61R..75.
  | url = http://articles.adsabs.harvard.edu/full/1951JBAA...61R..75.
  | access-date = 10 June 2016
}}</ref>

== Biography ==
Milne was born in [[Kingston upon Hull|Hull]], Yorkshire, England. He attended [[Hymers College]] and from there he won an open scholarship in mathematics and natural science to study at [[Trinity College, Cambridge]] in 1914, gaining the largest number of marks which had ever been awarded in the examination.{{cn|date=January 2020}} In 1916 he joined a group of mathematicians led by [[A. V. Hill]] for the Ministry of munitions working on the ballistics of anti-aircraft gunnery, they became known as ′Hill's Brigands′.  Later Milne became an expert on sound localisation.<ref>Van der Kloot, W.(2011). ″Mirrors and smoke: A. V. Hill, his brigands, and the science of anti-aircraft gunnery in world war I.″ Notes Rec. R. Soc. Lond. '''65''': 393–410.</ref>  In 1917 he became a lieutenant in the [[Royal Naval Volunteer Reserve]].  He was a fellow of Trinity College, Cambridge, 1919–1925, being assistant director of the [[Sun|solar]] physics observatory, 1920–1924, mathematical lecturer at Trinity, 1924–1925, and university lecturer in astrophysics, 1922–1925. He was [[Beyer Chair of Applied Mathematics|Beyer professor of applied mathematics]], [[Victoria University of Manchester]], 1924–1928, before his appointment as [[Rouse Ball Professor of Mathematics]] and to a fellowship at [[Wadham College, Oxford]], in 1928. Milne's earlier work was in mathematical astrophysics. Much of his research in the 1930s was concerned with the [[theory of relativity]] and [[Physical cosmology|cosmology]]. His later work, concerned with the interior structure of stars, aroused controversy. Milne was [[President of the Royal Astronomical Society]], 1943–1945.  During World War II he again worked on ballistics.

Milne married Margaret Scott Campbell on 26{{Nbsp}}June 1928 at [[Withington]], Manchester. Campbell, from [[Dornoch]], [[Sutherland]], Scotland, was the daughter of Hugh Fraser Campbell, an [[Advocate#Scotland|advocate]] in [[Aberdeen]]. Milne's brother, Geoffrey, then a lecturer in [[agricultural chemistry]] at the [[University of Leeds]], was best man.<ref name="Leeds Mercury 27 June 1928">{{Cite news|author=<!--Staff writer(s); no by-line.--> |title=University Professor Weds |date=27 June 1928 |page=5 |work=[[Leeds Mercury]] |location=Leeds |language=en |oclc=1016307518 |via=British Newspaper Archive |url=https://www.britishnewspaperarchive.co.uk/viewer/bl/0000748/19280627/155/0005 |access-date=13 August 2021 |url-access=subscription}}</ref> Margaret Scott Milne died on the 5{{Nbsp}}October 1938 at [[Oxford]].<ref name="Aberdeen Press 10 October 1938">{{Cite news|author=<!--Staff writer(s); no by-line.--> |title=Deaths |date=10 October 1938 |work=[[The Press and Journal (Scotland)|Aberdeen Press and Journal]] |page=1 |language=en |issn=2632-1165 |oclc=271459455 |via=British Newspaper Archive |url=https://www.britishnewspaperarchive.co.uk/viewer/bl/0000577/19381010/175/0001 |access-date=13 August 2021 |url-access=subscription}}</ref> He married secondly, Beatrice Brevoort Renwick, the third daughter of William Whetten Renwick, on 22{{Nbsp}}June 1940 at [[St Andrew's Church, Oxford|St Andrew's Church]], Oxford.<ref name="The Times 15 June 1940">{{Cite news|author=<!--Staff writer(s); no by-line.--> |title=Forthcoming Marriages |date=15 June 1940 |page=9 |work=[[The Times]] |issn=0140-0460 |issue=48643 |id={{Gale|CS151729871}}}}</ref><ref name="The Times 25 June 1940">{{Cite news|author=<!--Staff writer(s); no by-line.--> |title=Marriages |date=25 June 1940 |page=1 |work=[[The Times]] |issn=0140-0460 |issue=48651 |id={{Gale|CS17118937}}}}</ref> William Whetten was the nephew of American architect [[James Renwick Jr.]], and designed [[Saints Peter and Paul Cathedral (Indianapolis)|Saints Peter and Paul]], a [[Catholic Church|Roman Catholic]] cathedral in [[Indianapolis, Indiana|Indianapolis]], Indiana, United States.<ref>{{Cite book |last1=Divita |first1=James J. |editor1-last=Bodenhamer |editor1-first=David J. |editor2-last=Barrows |editor2-first=Robert Graham |editor3-last=Vanderstel |editor3-first=David Gordon |display-editors=1 |year=1994 |title=The Encyclopedia of Indianapolis |chapter=General Entries |publisher=[[Indiana University Press]] |page=1216 |location=Indianapolis |language=en |isbn=978-0-253-31222-8 |oclc=940538156 |via=The Encyclopedia of Indianapolis |chapter-url=https://comet.soic.iupui.edu/deoi/ss-peter-and-paul-cathedral/ |access-date=13 August 2021 |url-status=live |archive-url=https://web.archive.org/web/20210813093757/https://comet.soic.iupui.edu/deoi/ss-peter-and-paul-cathedral/ |archive-date=13 August 2021}}</ref> Beatrice Brevoort Milne died at Oxford on 28{{Nbsp}}August 1945, aged just 32 years.<ref name="The Times 30 August 1945">{{Cite news|author=<!--Staff writer(s); no by-line.--> |title=Deaths |date=30 August 1945 |page=1 |work=[[The Times]] |issn=0140-0460 |issue=50234 |id={{Gale|CS17252638}}}}</ref> Milne died of a heart attack in [[Dublin]], Ireland, while preparing to give a set of lectures. These can be found written down in one of his last published books: ''Modern Cosmology and the Christian Idea of God'' (1952).

==Research into stellar atmospheres and structure==
In the 1920s much of Milne's research was concerned with [[star]]s, particularly the outer layers known as [[stellar atmosphere]]s that produce the radiation observed from the Earth. He considered a [[grey atmosphere]], a simplifying approximation in which the strength of the absorption of light by the hot ionized gas is the same at all wavelengths. This produced predictions of how temperature varies through the atmosphere, including the mathematical expression now known as the Milne Equation. He also calculated how the intensity of light from a star varies with wavelength on the basis of this model.<ref name="chandrasekhar1980">{{cite journal
 | last = Chandrasekhar
 | first = S.
 | author-link = Subrahmanyan Chandrasekhar 
 | title = The 1979 Milne Lecture – Edward Arthur Milne: His Part in the Development of Modern Astrophysics
 | journal = [[Quarterly Journal of the Royal Astronomical Society]]
 | volume = 21
 | number = 2
 | pages = 93–107
 | date = 1980
 | bibcode = 1980QJRAS..21...93C
 | url = http://articles.adsabs.harvard.edu/full/1980QJRAS..21...93C
 | access-date = 12 June 2016
}}</ref><ref name="tayler1996">{{cite journal
 | last = Tayler
 | first = R. J.
 | author-link = Roger Tayler
 | title = E. A. Milne (1896–1950) and the Structure of Stellar Atmospheres and Stellar Interiors
 | journal = [[Quarterly Journal of the Royal Astronomical Society]]
 | volume = 37
 | number = 3
 | pages = 355–363
 | date = 1996
 | bibcode = 1996QJRAS..37..355T
 | url = http://articles.adsabs.harvard.edu/full/1996QJRAS..37..355T
 | access-date = 12 June 2016
}}</ref>

Milne moved on to consider the more realistic case where the strength of the absorption of light by gas within stars (expressed by the absorption coefficient) does vary with wavelength. Using simplifying assumptions he calculated how for the Sun
the strength of the absorption depends on wavelength. His results could not be explained adequately at the time, but later
[[Hydrogen anion|negatively-charged hydrogen ions]] (H<sup>−</sup>) were shown to be a major contributor to Milne's results.<ref name="tayler1996"/>

Milne, working with [[Ralph H. Fowler]], studied how the strengths of spectral lines of stars depend on their spectral type. In doing this they applied the work of [[Meghnad Saha]] about the ionization of gases to stellar atmospheres.<ref name="tayler1996"/>

Milne worked on the structures and interiors of stars in the late 1920s and early 1930s. He often took opinions opposed to those of [[Arthur Eddington]].<ref name="tayler1996"/>

==Research into cosmology and relativity==
From the early 1930s, Milne's interests focused increasingly on [[relativity theory]] and [[Physical cosmology|cosmology]].<ref name="whitrow1996">{{cite journal
 | last = Whitrow
 | first = G. J.
 | author-link = Gerald James Whitrow
 | title = E. A. Milne and Cosmology
 | journal = [[Quarterly Journal of the Royal Astronomical Society]]
 | volume = 37
 | number = 3
 | pages = 365–367
 | date = 1996
 | bibcode = 1996QJRAS..37..365W
 | url = http://articles.adsabs.harvard.edu/full/1996QJRAS..37..365W
 | access-date = 12 June 2016
}}</ref>

From 1932 he worked on the problem of the "expanding universe" and in ''Relativity, Gravitation, and World-Structure'' (1935), proposed an [[Non-standard cosmology|alternative]] to [[Albert Einstein]]'s [[general relativity]] theory. With McCrea (1934) he also showed that the three models which form the foundations of modern cosmology first proposed by Friedmann (1922) using the general theory of relativity, can also be derived using only Newtonian mechanics.<ref name="mccrea_milne_1934">{{cite journal
 | last1 = McCrea 
 | first1 = W. H. 
 | author1-link = William McCrea (astronomer)
 | last2 = Milne 
 | first2 = E. A. 
 | title = Newtonian universes and the curvature of space
 | journal = [[Quarterly Journal of Mathematics]]
 | volume = 5 
 | pages = 73–80
 | date = 1934 
|bibcode = 1934QJMat...5...73M |doi = 10.1093/qmath/os-5.1.73 | citeseerx = 10.1.1.630.3318 
 }} This Newtonian derivation is sometimes incorrectly also ascribed to Friedmann.</ref>

Milne's alternative to general relativity theory based on [[kinematics]] was known as Kinematic Relativity. His theory was built on the special but not general theory of relativity. Because of this it has been described as a "nonrelativistic cosmology".<ref>Nye, Mary Jo. (2003). ''The Cambridge History of Science: Volume 5, The Modern Physical and Mathematical Sciences''. Cambridge University Press. p. 529. {{ISBN|0-521-57243-6}}</ref> Milne’s theory met with opposition from others but inspired the steady-state theorists.<ref>Levy, Michael I. (2010). ''The Universe: A Historical Survey of Beliefs, Theories, and Laws''. Britannica Educational Publishing. p. 185. {{ISBN|978-1-61530-055-6}}</ref>

== ''Relativity, Gravitation, and World Structure'' ==
The main difference between the [[Milne model]] of an expanding universe, and the current (Einstein's) model of an expanding universe was that Milne did not assume ''a priori'' that the universe has a homogeneous matter distribution.  He did not include the gravitation interaction into the model either.

Milne argued that under the context of Einstein's special relativity, and the relativity of simultaneity, that it is impossible for a nonstatic universe to be homogeneous.  Namely, if the universe is spreading out, its density is decreasing over time, and that if two regions appeared to be at the same density at the same time to one observer, they would not appear to be the same density at the same time to another observer.  However, if each observer measures its local density at the same agreed-upon proper time, the measured density should be the same.  In Minkowskian coordinates, this constant proper time forms a hyperbolic surface which extends infinitely to the light-cone of the event of creation. This is true even when proper time approaches 0, the time of the creation.  The universe is already infinite at the creation time!

Milne's model is, therefore, that of a sphere, with an approximately homogeneous matter distribution within several billion light years of the center which then increases to an infinite density.  It can be shown that this infinite density is actually the density of the universe when at the time of the big bang.  The spherical distribution is unique in that it is essentially the same after a Lorentz transformation, except that a different stationary particle is at the center.  As it is the only distribution that has this property, it is the only distribution which could satisfy the cosmological principle of "no preferred reference frame." Based on this cosmological principle Milne created a model that can be described entirely within Euclidean geometry.

As of 1935, using this model, Milne published a prediction of the cosmic background radiation which appears to be of a much different character than that predicted by Eddington.  In fact, many passages in ''Relativity, Gravitation and World Structure'' are devoted to attacking Eddington's preconceptions.

==Religious views==

Milne was a Christian [[Theism|theist]].<ref name="McCrea 1953">{{cite journal|author=McCrea, W. H.|year=1953|title=Reviewed Work: Modern Cosmology and the Christian Idea of God by E. A. Milne|journal=[[The Mathematical Gazette]]|volume=37|issue=370|pages=137–139|doi=10.2307/3608962|jstor=3608962}}</ref><ref>{{cite journal|author=Painter, Alfred W.|year=1953|title=Reviewed Work: Modern Cosmology and the Christian Idea of God by E. A. Milne|journal=[[The Journal of Religion]]|volume=33|issue=2|pages=156|doi=10.1086/484426}}</ref> In 1950, Milne gave ten lectures on Christianity and cosmology for the Edward Cadbury lectures which he was invited to give at the [[University of Birmingham]]. The lectures were published in the book ''Modern Cosmology and the Christian Idea of God'', edited by [[Gerald James Whitrow]] and published in 1952.<ref name="McCrea 1953"/>

Milne was a [[Theistic evolutionism|theistic evolutionist]] who held the view that God intervenes with "deft touches" to steer mutations in the right direction.<ref>Bowler, Peter J. (2001). ''Reconciling Science and Religion: The Debate in Early-Twentieth-Century Britain''. University of Chicago Press. p. 413. {{ISBN|0-226-06858-7}}</ref>

==Honours==
===Awards===
*[[Member of the Most Excellent Order of the British Empire|MBE]] (1918)
*[[Smith's Prize]] (1922)
*[[Gold Medal of the Royal Astronomical Society]] (1935)
*[[Royal Society]]'s [[Royal Medal]] (1941)
*[[Bruce Medal]] (1945)
===Named after him===
*[[Milne (crater)|Milne]], a crater on the [[Moon]]
*The E.A. Milne Centre for Astrophysics at the [[University of Hull]] (opened 2015)<ref>{{cite web|url=http://www.milne.hull.ac.uk|title=E.A. Milne Centre for Astrophysics, University of Hull – University of Hull}}</ref>

== Books by Milne ==
* ''Thermodynamics of the Stars'', Berlin: J. Springer, 1930.
* ''The White Dwarf Stars'', Oxford: [[Clarendon Press]], 1932.
* ''Relativity, gravitation and world-structure'', Oxford: [[Clarendon Press]], 1935.
* ''The Inverse Square Law of Gravitation'', London: Harrison and Son, 1936.
* ''The Fundamental Concepts of Natural Philosophy'', Edinburgh: Oliver & Boyd, 1943.
* ''Kinematic relativity; a sequel to Relativity, gravitation and world structure'', Oxford: Clarendon Press, 1948.
* ''[[Vectorial Mechanics]]'', New York: Interscience Publishers, 1948.
* ''Modern Cosmology and the Christian Idea of God'', Oxford: [[Clarendon Press]], 1952.
* ''Sir James Jeans: A Biography'', [[Cambridge University Press]], 1952.

==See also==

*[[Alternatives to general relativity]]
*[[Herbert Dingle#Controversies|Herbert Dingle § Controversies]]
*[[List of science and religion scholars]]
*[[Blanketing effect]]
*[[Dirac large numbers hypothesis]]
*[[Non-equilibrium_thermodynamics#Milne's_definition_in_terms_of_radiative_equilibrium|Milne's definition of local thermodynamic equilibrium]]
*[[Saha ionization equation]]

== Notes ==
{{reflist}}

== References ==
*[http://www.worldscientific.com/worldscibooks/10.1142/p856 Beating the Odds: The Life and Times of E.A Milne] by Meg Weston Smith, in June 2013. Published by [http://www.worldscientific.com World Scientific Publishing Co].
*Gale, George, "[http://setis.library.usyd.edu.au/stanford/entries/cosmology-30s/ Cosmology: Methodological Debates in the 1930s and 1940s]," [[Stanford Encyclopedia of Philosophy]]. Milne was a major player in the cosmological controversies described in this article.

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  before=[[Sydney Chapman (mathematician)|Sydney Chapman]]  |
  title=[[Beyer Chair of Applied Mathematics]] at [[University of Manchester]] |
  years=1925–1928|
  after=[[Douglas Hartree]] 
}}
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{{DEFAULTSORT:Milne, Edward Arthur}}
[[Category:1896 births|Milne, Arthur]]
[[Category:1950 deaths|Milne, Arthur]]
[[Category:20th-century British mathematicians|Milne, Arthur]]
[[Category:Academics of the Victoria University of Manchester]]
[[Category:Alumni of Trinity College, Cambridge]]
[[Category:British Christian writers]]
[[Category:20th-century British astronomers|Milne, Arthur]]
[[Category:English physicists|Milne, Arthur]]
[[Category:Fellows of the Royal Society|Milne, Arthur]]
[[Category:Fellows of Trinity College, Cambridge|Milne, Arthur]]
[[Category:Fellows of Wadham College, Oxford|Milne, Arthur]]
[[Category:Mathematicians from Kingston upon Hull]]
[[Category:People educated at Hymers College|Milne, Arthur]]
[[Category:Presidents of the Royal Astronomical Society]]
[[Category:Recipients of the Gold Medal of the Royal Astronomical Society]]
[[Category:Relativity critics]]
[[Category:Rouse Ball Professors of Mathematics (University of Oxford)]]
[[Category:Royal Medal winners]]
[[Category:Scientists from Kingston upon Hull|Milne, Arthur]]
[[Category:Theistic evolutionists]]
[[Category:Writers about religion and science]]
[[Category:Royal Navy officers]]
[[Category:Royal Naval Volunteer Reserve personnel of World War I]]
[[Category:Military personnel from Kingston upon Hull]]
[[Category:20th-century British physicists]]