Keywords: age of the universe, cosmic time, cosmological constant, Hubble constant, exergy flow, RUM, radiating universe model, lumped capacitance method
An exergetic approach to the age of universe
Recent finding by Bond et al. (2013) about the age of the star HD 140283 (14.46 ± 0.8 Gyr) requires us to reconsider the estimates about the age of the universe, namely 13.817 ± 0.048 Gyr. Their conflicting result is analytically supported by the paper in Int. J. Exergy by Kilkis (2004). This paper, which introduced the Radiating Universe Model (RUM) with exergy flow to an infinitely–sized thermal bath at 0 K, predicted that the age of the universe is 14.885 ± 0.040 Gyr. It further calculated that Hubble constant is 65.7 km s−1Mpc−1 and the expansion of the universe has been accelerating since the cosmic age of 4.4 Gyr due to a positive, time dependent cosmological number that is slightly decreasing and presently it is 8.8 × 10−36 s−2. The exergy flow rate, solved by the lumped–capacitance method, changes with the square of cosmic time and is currently 1.224 × 1050 erg·s−1.