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{{EngvarB|date=October 2013}}
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{{Use dmy dates|date=October 2013}}
{{Infobox scientist
| name = George Johnstone Stoney
| image = GeorgeJohnstoneStoney(1826-1911),Undated(DateGuessedEarly1890s).jpg
| birth_date = {{Birth date|1826|2|15|df=yes}}
| birth_place = Oakley Park
| death_date = {{Death date and age|1911|7|5|1826|2|15|df=yes}}
| death_place = [[Notting Hill]], London
}}
'''George Johnstone Stoney''' (15 February 1826 – 5 July 1911) was an [[Anglo-Irish]] physicist. He is most famous for introducing the term ''[[electron]]'' as the "fundamental unit quantity of electricity".<ref name = "stoney11">{{cite web |url= http://www.offalyhistory.com/articles/264/1/George-Johnstone-Stoney-1826-1911/Page1.html|title=George Johnstone Stoney 1826–1911|author=Obituary in ''The Daily Express'' newspaper|date= 6 July 1911}}</ref>
He had introduced the concept, though not the word, as early as 1874 and 1881, and the word came in 1891.<ref>[http://www.chemteam.info/Chem-History/Stoney-1894.html Stoney Uses the Term Electron<!-- bot-generated title -->]</ref>&nbsp;
<ref>{{cite book|author=Jammer, Max |title=Concepts of Force – A Study of the Foundations of Dynamics|location=New York | publisher=Dover Publications, Inc.|year=1956|isbn=0-486-40689-X}}</ref>
<ref name="On_Physical_Units">Stoney, G.J. (1881). "On the Physical Units of Nature." ''Phil. Mag.'' [5] 11, 381.</ref> He published around 75 scientific papers during his lifetime.
 
==Education and employment positions==
Stoney was born at Oakley Park, near [[Birr]], [[County Offaly]], in the [[Irish Midlands]], in an old-established Anglo-Irish family.<ref name=JGOHara>"George Johnstone Stoney, 1826–1911", by James G O'Hara, page 126 in the book {{cite book|last= McCartney|first= Mark|coauthors= Andrew Whitaker (editors)|year= 2003|title= Physicists of Ireland: Passion and Precision|pages=298|publisher=IOP Publishing|isbn= 0-7503-0866-4}}</ref> He attended [[Trinity College, Dublin]], graduating with a B.A. in 1848. From 1848 to 1852 he worked as an astronomy assistant to [[William Parsons, 3rd Earl of Rosse]] at Birr Castle, County Offaly, where Parsons had built the world's largest telescope, the 72-inch [[Leviathan of Parsonstown]]. Simultaneously Stoney continued to study physics and mathematics and was awarded an M.A. by Trinity College Dublin in 1852.
 
From 1852 to 1857 he was professor of physics at [[Queen's College Galway]]. From 1857 to 1882 he was employed as Secretary of the [[Queen's University of Ireland]], an administrative job based in Dublin. In the early 1880s he moved to the post of superintendent of Civil Service Examinations in Ireland, a post he held until his retirement in 1893. In that year, he took up residence in London. Stoney died in 1911 at his home in [[Notting Hill]], London.<ref name = "stoney11">{{cite web |url= http://www.offalyhistory.com/articles/264/1/George-Johnstone-Stoney-1826-1911/Page1.html|title=  George Johnstone Stoney 1826–1911|accessdate=22 October 2008|date= 6 July 1911|publisher=The Daily Express}}</ref> During his decades of non-scientific employment responsibilities in Dublin, Stoney continued to do scientific research on his own. He also served for decades as honorary secretary and then vice-president of the [[Royal Dublin Society]], a scientific society modelled after the Royal Society of London, and after his move to London Stoney served on the council of that society too. Additionally he intermittently served on scientific review committees of the [[British Association for the Advancement of Science]] from the early 1860s on.
 
== Stoney's scientific output ==
Stoney published seventy-five scientific papers in a variety of journals, but chiefly in the journals of the Royal Dublin Society. He made significant contributions to cosmic physics and to the theory of gases. He estimated the number of [[molecule]]s in a cubic millimetre of gas, at room temperature and pressure, from data obtained from the kinetic theory of gases. Stoney's most important scientific work was the conception and calculation of the magnitude of the "atom of electricity". In 1891, he proposed the term '[[electron]]' to describe the fundamental unit of electrical charge, and his contributions to research in this area laid the foundations for the eventual discovery of the particle by [[J.J. Thomson]] in 1897.
 
He was elected a [[Fellow of the Royal Society]] in June 1861 on the basis of being ''the author of papers on "The Propagation of Waves," "On the Rings seen in Fibrous Specimens of Calc Spar," and Molecular Physics, published in the Transactions of the Royal Irish Academy, et cetera, Distinguished for his acquaintance with the science of Astronomy & General Physics''.<ref>{{cite web |url=http://www2.royalsociety.org/DServe/dserve.exe?dsqIni=Dserve.ini&dsqApp=Archive&dsqCmd=Show.tcl&dsqDb=Persons&dsqPos=2&dsqSearch=%28Surname%3D%27stoney%27%29|title= Library and Archive catalogue|publisher= Royal Society |accessdate= 22 October 2010}}</ref>
 
=== The Stoney scale ===
Contemporary physics has settled on the [[Planck scale]] as the most suitable scale for a [[unified theory]]. The Planck scale was, however, anticipated by George Stoney.<ref name="On_Physical_Units" /> Like Planck after him, Stoney realised that large-scale effects such as gravity and small-scale effects such as electromagnetism naturally imply an intermediate scale where physical differences might be rationalised. This intermediate scale comprises units ([[Stoney scale units]]) of mass, length, time etc., yet mass is the cornerstone.
 
The Stoney mass ''m''<sub>S</sub> (expressed in contemporary terms):
 
:<math>m_S=\sqrt{\frac{e^2}{4 \pi \varepsilon_0 G}} = \sqrt{\alpha}\, m_P </math>
 
where ε<sub>0</sub> is the [[permittivity of free space]], ''e'' is the [[elementary charge]] and ''G'' is the [[gravitational constant]], and where α is the [[fine-structure constant]] and  ''m''<sub>P</sub> is the [[Planck mass]].
 
Like the Planck scale, the Stoney scale functions as a symmetrical link between microcosmic and macrocosmic processes in general and yet it appears uniquely oriented towards the unification of electromagnetism and gravity . Thus for example whereas the [[Planck length]] is the mean square root of the reduced [[Compton wavelength]] and half the [[gravitational radius]] of any mass, the Stoney length is the mean square root of the 'electromagnetic radius' (see [[Classical electron radius]]) and half the gravitational radius of any mass, ''m'':
 
:<math>\ell_P=\sqrt{\frac{\hbar}{m c}\cdot\frac{G m}{c^2}}</math>
 
:<math>\ell_S=\sqrt{\frac{e^2}{4 \pi \varepsilon_0 m c^2}\cdot\frac{G m}{c^2}}</math>
 
where <math>\hbar \ </math> is the reduced [[Planck's constant]] and ''c'' is the [[speed of light]]. It should be noted however that these are only mathematical constructs since there must be some practical limit to how small a length can get. If the Stoney length is the minimum length then either a body's electromagnetic radius or its half gravitational radius is a physical impossibility, since one of these must be smaller than the Stoney length. If [[Planck length]] is the minimum then either a body's reduced Compton wavelength or its half gravitational radius is a physical impossibility since one of these must be smaller than the Planck length. Moreover, the Stoney length and Planck length cannot both be the minimum length.
 
According to contemporary convention, Planck scale is the scale of [[vacuum energy]], below which space and time do not retain any physical significance. This prescription mandates a general neglect of the Stoney scale within the scientific community today. Previous to this mandate, [[Hermann Weyl]] made a notable attempt to construct a unified theory by associating a gravitational unit of charge with the Stoney length. Weyl's theory led to significant mathematical innovations but his theory is generally thought to lack physical significance.<ref>O'Raifeartaigh L., ''The Dawning of Gauge Theory,'' Princeton Uni Press, 1997</ref><ref>Gorelik G., ''Hermann Weyl and Large Numbers in Relativistic Cosmology,'' Einstein Studies in Russia, Ed Balashov Y. and Vizgin V., Boston (Birkhaeuser) 2002</ref>
 
==Other==
Stoney married his cousin, Margaret Sophia, by whom he had had two sons and three daughters. For most of his decades in Dublin, Stoney resided in the [[Dundrum, Dublin]] neighbourhood. The street that he lived on was later renamed Stoney Road in his memory. After Stoney died in London, his cremated ashes were buried in [[St. Nahi's Church]] in Dundrum.
 
One of Stoney's sons, George Gerald Stoney, was a scientist. But a more scientifically notable relative was Stoney's nephew, the Dublin-based physicist [[George FitzGerald]] (1851–1901). Stoney and FitzGerald were in regular communication on scientific matters. In addition, on political matters, both Stoney and FitzGearld were active opponents of the [[Irish Home Rule Movement]]. In their political opinion, the spirit of Irish Home Rule and later Irish nationalism was contrary to the spirit of science. Stoney resigned from his job as Secretary of Queen's University of Ireland in 1882 in objection to a government decision to introduce "sectarianism" into the system; i.e., Stoney wanted to keep the system non-denominational, but the government acceded to Irish Catholic demands for Catholic institutions.
 
[[Impact crater|Craters]] on [[Mars]] and the [[Moon]] are named in his honour.
 
His brother [[Bindon Blood Stoney]] was Engineer of Dublin Port is renowned for building a number of the main Dublin bridges, and developing the Quayside, as well as other engineering projects.
 
==See also==
*[[Stoney units]]
*[[Basic concepts of quantum mechanics]]
*[[Planck units]]
 
==References==
{{reflist}}
 
==Bibliography==
*''The Infancy of Atomic Physics. Hercules in His Cradle'', by Alex Keller. Oxford University 1983. ISBN 0-19-853904-5
* "George Johnstone Stoney, FRS, and the concept of the electron", by J.G. O'Hara (12 pages) (year 1975) [http://www.jstor.org/pss/531468 ref].
*[http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Stoney-1894.html Of the "Electron", or Atom of Electricity] – by G. J. Stoney, Philosophical Magazine, Series 5, Volume 38, p.&nbsp;418–420, October 1894
 
{{Authority control|VIAF=67239096}}
{{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
| NAME              = Stoney, George Johnstone
| ALTERNATIVE NAMES =
| SHORT DESCRIPTION =[[Anglo-Irish]] physicist
| DATE OF BIRTH    = 15 February 1826
| PLACE OF BIRTH    =Oakley Park
| DATE OF DEATH    = 5 July 1911
| PLACE OF DEATH    =[[Notting Hill]], London
}}
{{DEFAULTSORT:Stoney, George Johnstone}}
[[Category:1826 births]]
[[Category:1911 deaths]]
[[Category:People from County Offaly]]
[[Category:Irish physicists]]
[[Category:British physicists]]
[[Category:Fellows of the Royal Society]]

Latest revision as of 22:34, 14 February 2014

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