My apartment is messy and it keeps getting messier. There are a lot of papers and books scattered about, and some dirty dishes too, but this isn’t my fault. The laws of physics mean it has to be this way. My apartment, my desk at work, and the rest of the universe all follow the Second Law of Thermodynamics.
About a century ago, scientists and engineers first developed thermodynamics to help understand how steam engines work and how to make them more efficient. Over time, these laws have changed and we’ve found they apply to almost any natural or manmade system.
- The First Law: Energy cannot be created or destroyed, but it can change forms.
- The Second Law: Entropy, the degree of disorder in a system, can only increase. If you’re lucky, it will stay the same for a while, but it won’t decrease. Also, if you combine two systems the entropy of the new system will be greater than the sum of its original parts.
- The Third Law: It is impossible to reach a temperature of absolute zero.
Using my apartment as an example, I could clean it, thus reducing the entropy; however, I would also increase the entropy in the garbage dumpster outside, and my work would generate heat, increasing the disorder in the atmosphere by some small degree. In the end, the total entropy of my apartment, the dumpster, and the atmosphere would be greater than when I started.
The second law predicts that someday in the far distant future the combined entropy of the universe will be so great that no ordered systems will exist at all. It’s called heat death, and it’s a depressing concept. It will be the end of machines, the end of apartments (dirty or otherwise), and the end of life since life is an orderly system just like steam engines.
There is one good thing about entropy, at least for artistic folks like myself. It’s a scientific principle full of potential symbolism and philosophical meaning.
Hawking, Steven W. A Brief History of Time: From the Big Bang to Black Holes. NY: Bantam Books, 1998.
Rubi, J. Miguel. “The Long Arm of the Second Law.” Scientific American November 2008. Pages 62-67.