Erg: Difference between revisions

The '''erg''' is a unit of energy equal to 10⁻⁷{{nbsp}}[[joule]]s (100{{nbsp}}[[Nano-|n]]J). It is not an [[SI unit]], instead originating from the [[centimetre–gram–second system of units]] (CGS). Its name is derived from {{Transliteration|grc|ergon}} ({{lang|grc|ἔργον}}), a [[Greek language|Greek]] word meaning 'work' or 'task'.<ref>{{cite book |url=https://books.google.com/books?id=0UkuAAAAYAAJ |title=The Greek in English |last=Goodell |first=Thomas Dwight |publisher = [[Henry Holt and Company]] |edition=2nd |year=1889 |page=40}}</ref>

In 1864, [[Rudolf Clausius]] proposed the Greek word {{lang|grc|ἐργον}} ({{Transliteration|grc|ergon}}) for the unit of energy, work and heat.<ref name="Clausius_1867"/><ref name="Howard_2002"/> In 1873, a committee of the [[British Association for the Advancement of Science]], including British physicists [[James Clerk Maxwell]] and [[William Thomson, 1st Baron Kelvin|William Thomson]] recommended the general adoption of the centimetre, the gramme, and the second as fundamental units ([[Centimetre–gram–second system of units|C.G.S. System of Units]]). To distinguish derived units, they recommended using the prefix "C.G.S. unit of ..." and requested that the word ''erg'' or ''ergon'' be strictly limited to refer to the ''C.G.S. unit of energy''.<ref name="BSAS_1873"/>

The erg is not a part of the [[International System of Units]] (SI), which has been recommended since 1 January 1978<ref>{{Cite book|url=https://books.google.com/books?id=6N68sMtqXSUC&q=1+January+1978%2C+erg&pg=PA3|title=Architects' Data|last1=Neufert|first1=Ernst|last2=Neufert|first2=Peter|last3=Kister|first3=Johannes|date=2012-03-26|publisher=John Wiley & Sons|isbn=9781405192538|language=en}}</ref> when the [[European Economic Community]] ratified a directive of 1971 that implemented SI as agreed by the [[General Conference on Weights and Measures|General Conference of Weights and Measures]].<ref>{{Cite journal|last=Jennings|first=W. A.|date=October 1972|title=SI units in radiation measurement|url=https://www.birpublications.org/doi/abs/10.1259/0007-1285-45-538-784?journalCode=bjr|journal=The British Journal of Radiology|language=en|volume=45|issue=538|pages=784–785|doi=10.1259/0007-1285-45-538-784|pmid=5078949|issn=0007-1285|url-access=subscription}}</ref> It is the unit of energy in [[Gaussian units]], which are widely used in [[astrophysics]]<ref>{{Cite web|url=https://physics.stackexchange.com/q/235581 |title=Are ergs commonly used in astrophysics? If so, is there a specific reason for it?|date=2016-02-12|website=Physics Stack Exchange|access-date=2018-09-15}}</ref>{{better source needed|reason=User-generated content|date=July 2021}}, applications involving microscopic problems and relativistic electrodynamics,<ref>{{cite book |last1=Jackson |first1=John David |title=Classical electrodynamics |date=2009 |publisher=Wiley |location=Hoboken, NY |isbn=978-0-471-30932-1 |page=784 |edition=3}}</ref> and sometimes in [[mechanics]]{{citation needed|date=November 2023}}.