The large-number hypothesis and the Earth's expansion

The equation of state of the terrestrial material obtained from seismic data is adopted to construct three zone earth models under hypothesis of variable constant of gravity G as proposed by Dirac. Three hypotheses are investigated: variable G without creation, creation such that m (mass) is proportional to G-1, and multiplicative creation, m is proportional to G-2. It is shown that, with the currently accepted value of the Hubble constant, dR/dt = 7 x 10-3 cm yr-1, dR/dt = 1.9 x 10-2 cm yr-1 and dR/dt = 2.5 x 10-2 cm yr-1 for each hypothesis. On the multiplicative creation, the Earth radius would have been 5100 km, which is in agreement with the estimate by some geophysicists. (Auth.)