Editing Arthur Eddington (section)

== Fundamental theory and the Eddington number ==
<!-- This section is linked from [[Chandrasekhar limit]] & redirect [[Fundamental theory (Eddington)]] -->
During the 1920s until his death, Eddington increasingly concentrated on what he called "[[Classical unified field theories#Eddington's affine geometry|fundamental theory]]" which was intended to be a unification of [[Quantum mechanics|quantum theory]], [[theory of relativity|relativity]], cosmology, and [[gravitation]]. At first he progressed along "traditional" lines, but turned increasingly to an almost [[numerology|numerological]] analysis of the dimensionless ratios of fundamental constants.

His basic approach was to combine several fundamental constants in order to produce a dimensionless number. In many cases these would result in numbers close to 10<sup>40</sup>, its square, or its square root. He was convinced that the mass of the [[proton]] and the charge of the [[electron]] were a "natural and complete specification for constructing a Universe" and that their values were not accidental. One of the discoverers of quantum mechanics, [[Paul Dirac]], also pursued this line of investigation, which has become known as the [[Dirac large numbers hypothesis]].<ref>{{cite book |last1=Srinivasan |first1=G. |title=What Are the Stars? |date=2014 |publisher=Springer Science & Business Media |location=Berlin |isbn=978-3642453021 |page=31 }}</ref>
A somewhat damaging statement in his defence of these concepts involved the [[fine-structure constant]], ''α''. At the time it was measured to be very close to 1/136, and he argued that the value should in fact be exactly 1/136 for [[epistemological]] reasons. Later measurements placed the value much closer to 1/137, at which point he switched his line of reasoning to argue that one more should be added to the [[Degrees of freedom (physics and chemistry)|degrees of freedom]], so that the value should in fact be exactly 1/137, the [[Eddington number]].<ref>{{Cite journal|last=Whittaker|first=Edmund|date=1945|title=Eddington's Theory of the Constants of Nature|journal=The Mathematical Gazette|volume=29|issue=286|pages=137–144|doi=10.2307/3609461|jstor=3609461|s2cid=125122360 }}</ref> [[mwod:wag|Wags]] at the time started calling him "Arthur Adding-one".<ref>{{cite book|author=Kean, Sam|title=The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of the Elements|year=2010|location=New York|publisher=Little, Brown and Co|url=https://books.google.com/books?id=Cky2x4wWvEUC&pg=PT241|isbn=978-0316089081}}</ref> This change of stance detracted from Eddington's credibility in the physics community. The current CODATA value is 1/{{physconst|alphainv|after=.}}

Eddington believed he had identified an algebraic basis for fundamental physics, which he termed "E-numbers" (representing a certain [[group (mathematics)|group]]&nbsp;– a [[Clifford algebra]]). These in effect incorporated [[spacetime]] into a higher-dimensional structure. While his theory has long been neglected by the general physics community, similar algebraic notions underlie many modern attempts at a [[grand unified theory]]. Moreover, Eddington's emphasis on the values of the fundamental constants, and specifically upon dimensionless numbers derived from them, is nowadays a central concern of physics. In particular, he predicted a number of hydrogen atoms in the Universe {{nowrap|136 × 2<sup>256</sup>}} ≈ {{val|1.57|e=79}}, or equivalently the half of the total number of particles protons + electrons.<ref>{{cite book |last1=Barrow |first1=J. D. |last2=Tipler |first2=F. J. |title=The Anthropic Cosmological Principle |publisher=Oxford University Press |location=Oxford |year=1986 |isbn=978-0198519492 |url=https://books.google.com/books?id=Agvg1qD7lUkC }}</ref> He did not complete this line of research before his death in 1944; his book ''Fundamental Theory'' was published posthumously in 1948.

=== Eddington number for cycling ===
Eddington is credited with devising a measure of a [[Cycling|cyclist's]] long-distance riding achievements. The Eddington number in the context of cycling is defined as the maximum number E such that the cyclist has cycled at least E '''miles''' on at least E days.<ref name=Jeffers2005>{{cite journal |last1=Jeffers |first1=David |last2=Swanson |first2=John |date=November 2005 |title=How high is your ''E''? |url=https://iopscience.iop.org/article/10.1088/2058-7058/18/10/30 |journal=Physics World |volume=18 |issue=10 |pages=21 |doi=10.1088/2058-7058/18/10/30 |access-date=2022-09-17}}</ref><ref>{{Cite web|url=http://tlatet.blogspot.com/2008/03/eddington-number.html|title=Eddington number|date=16 March 2008}}</ref>

For example, an Eddington number of 70 would imply that the cyclist has cycled at least 70 miles in a day on at least 70 occasions. Achieving a high Eddington number is difficult, since moving from, say, 70 to 75 will (probably) require more than five new long-distance rides, since any rides shorter than 75 miles will no longer be included in the reckoning. Eddington's own life-time E-number was 84.<ref>{{cite journal |author=<!--Editorial; no by-line.--> |date=July 2012 |title=Physics and sport |journal=Physics World |volume=25 |issue=7 |pages=15 |doi=10.1088/2058-7058/25/07/24 |bibcode=2012PhyW...25g..15. |doi-access=free }}</ref>

The Eddington number for cycling is analogous to the [[h-index|''h''-index]] that quantifies both the actual scientific productivity and the apparent scientific impact of a scientist.<ref name=Jeffers2005/>