What does the second law of thermodynamics state about the universe's entropy?

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. In fact, it can either increase or remain constant; however, the tendency in natural processes is for the entropy to increase. This principle implies that the flow of energy tends to result in more disordered configurations because, statistically speaking, there are far more ways for a system to be disordered than ordered.

Entropy is a measure of the randomness or disorder of a system. Thus, the second law indicates that natural processes will favor the direction of increasing entropy, leading to the conclusion that in the universe, as a whole, entropy tends to increase. This reflects the irreversible nature of physical processes, where systems spontaneously evolve towards states with higher degeneracy and disorder.

The other options suggest scenarios contrary to this fundamental principle. The universe cannot consistently decrease in entropy or maintain constant entropy without external intervention, nor can it achieve a perfectly balanced equilibrium in all scenarios since many processes are inherently spontaneous and irreversible. Understanding this increase in entropy is key to grasping the direction of spontaneous processes in nature.