String Theory is a 30 year old theory that, if proven, would provide a unified way of explaining the four fundamental forces of nature. It combines the strong and weak nuclear forces and electromagnetism with the very elusive force of gravity.
String theory has problems though.After 30 years an unproven theory would usually be counted a failure and scientists would move on to something more promising. However string theory still isn’t finished and, even if it were, there is no way to test it. Not only that, but strings, if they exist, are too small for us to measure now, or any time in the conceivable future. This has led some to accuse string theory of not even being a true scientific theory. Yet scientists spend a lot of time and money on it. This is a topic that heats up every so often. Now is one of those times.
- Peter Woit, a math professor at Columbia University is, and has been for the last 10 years, the most forceful critic of String Theory. He has a book called Not Even Wrong and writes very frequently about it on his blog, also called Not Even Wrong. Another book that covers some of the same ground is The Trouble with Physics by Lee Smolin. It’s an accessible book for a science amateur like me.
- Brian Greene, Woit’s colleague at Columbia University, is a huge proponent of string theory and has written some very readable explanations on the state of the theory and of theoretical physics in general. I’ve read and highly recommend The Fabric of the Cosmos. According to this Nautilus article, Woit and Greene have never actually gotten into a fist fight in the halls of Columbia.
- Quanta Magazine has an awesome graphic representation of all of the current, major Theories of Everything mapped with basic explanations of what the theories are and what we stand to learn from them.