The Laws of Thermodynamics

If one looks around the Internet, he or she can find a multitude of pages that state the laws of thermodynamics; so why add one more?  I've been writing a lot of posts on thermodynamics, but nowhere have I given a concise statement of the laws; also, I am not always happy with how the laws are described.  So this post is my contribution.

The Zeroth Law of Thermodynamics

The zeroth law states:

If two bodies are in thermal equilibrium with a third body, then they are in thermal equilibrium with each other.

The Heat Death of the Universe

This post is part of a series, Nonsense and the Second Law of Thermodynamics. The previous post is entitled Time's Arrow. The previous post is essential to understanding this post.

In most of the discussion of nonsense in this series, the nonsense stems from a poor understanding of physics.  This post introduces some nonsense that must be taken seriously.  Perhaps, this nonsense, also stems ultimately from a poor understanding of physics.  The people with the poor understanding this time, however, are some of the most brilliant minds in physics.

The School-Book Story

This discussion starts with the school-book story of the heat death of the universe.  By calling it the "school-book" story I do not mean to pooh-pooh it too much.  In fact, it is most likely the correct story.  Much of this post, however, will focus on caveats and complications to the story as it is usually told.

In thermodynamics, the universe is defined as the system and its surroundings.  We have seen that the second law requires that for any change the total entropy of the system and the surroundings must increase or stay the same.  As time goes by, therefore, the entropy of the universe increases.