Dirac's Cosmology and Mach's Principle

Abstract

DICKE discusses the three cosmological numbers: (1) which determines the gravitational constant, (2) which determines the Hubble age of the universe, and (3) the number of particles in the universe. They are related in that: (1) is roughly the reciprocal of (2) and (3) is roughly the square of (2). I assumed that these relations correspond to something fundamental in Nature. With an evolutionary universe (2) varies with time, and then (1) and (3) would also have to vary with time.