23. Relativity and magnetism by Benjamin Crowell, Light and Matter licensed under the Creative Commons Attribution-ShareAlike license.
Many people imagine Einstein's theory of relativity as something exotic and speculative. It's certainly not speculative at this point in history, since you use it every time you use a GPS receiver. But it's even less exotic than that. Every time you stick a magnet to your refrigerator, you're making use of relativity. The title of this chapter is “Electromagnetism,” but we'll start out by digging a little deeper into relativity as preparation for understanding what magnetism is and where it comes from.
23. Relativity and magnetism by Benjamin Crowell, Light and Matter licensed under the Creative Commons Attribution-ShareAlike license.