The universe is an isolated system, so according to the second law of thermodynamics, the energy in the universe available for useful work has always been decreasing. Therefore, the universe is not infinitely old—it had a beginning. Also, as one goes back in time, the energy available for work would eventually exceed the total energy in the universe, which, according to the first law of thermodynamics, remains constant. This is an impossible condition, showing in another way that the universe had a beginning.a
A further consequence of the second law is that soon after the universe began, it was more organized and complex than it is today—not in a highly disorganized and random state as assumed by evolutionists and proponents of the big bang theory.b