|1||is the Hubble constant today, the mean matter energy density today. The other constants are defined in Tables 1 and 2 and the definitions of the cosmological quantities are summarized in Appendix A.3.|
|2||After studying electrolysis in 1874, Johnstone Stoney suggested the existence of a “single definite quantity of electricity”. He was able to estimate the value of this elementary charge by means of Faraday’s laws of electrolysis. He introduced the term “electron” in 1894 and it was identified as a particle in 1897 by Thomson.|
|4||Again, is used either from or . I have chosen to use and .|
|11||The CODATA is the COmmittee on Data for Science and Technology, see http://www.codata.org/.|
|12||Note that the Dirac hypothesis can also be achieved by assuming that varies as . Indeed this reflects a choice of units, either atomic or Planck units. However, there is a difference: assuming that only varies violates the strong equivalence principle while assuming a varying results in a theory violating the weak equivalence principle. It does not mean that we are detecting the variation of a dimensionful constant but simply that either or is varying. This shows that many implementations of this idea are a priori possible.|
|13||For copper , for uranium and for lead .|
Living Rev. Relativity 14, (2011), 2
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