Eddington number

[Etymology: A. S. Eddington; UK 1882-1944] physics 10⁷⁹, the estimate by Eddington of the number of particles in the Universe. Somewhat oddly, this is only 1 away in exponent terms from the square of 10⁴⁰, which Paul Dirac
[Dirac P. A. M. Nature Vol. 139, 323 (1937)] subsequently showed to be the characteristic range of size in the Universe, e.g. of the radius of the Universe to that of the electron, the Coulomb force between proton and electron to the gravitational force between them.
[Petley B. W. The Fundamental Constants and the Frontier of Measurement (Boston, MA: Adam Hilger 1985)]