In previous chapters, the concepts of thermodynamic equilibrium, quasi-equilibrium processes, and energy and mass balances have been introduced and used to study processes that occur in engineering devices. It is clear that the First Law is an extremely powerful means to analyze real processes. However, as universal and powerful as it is, the First Law is not a complete description of thermodynamic processes.
The Crab Nebula is an excellent example of an irreversible process. It is a six-light-year-wide expanding remnant of a star’s supernova explosion. Japanese and Chinese astronomers recorded this violent event nearly 1,000 years ago in 1054, as did, almost certainly, Native Americans.