According to this video, electromagnetism is a relativistic phenomenon. Were you already familiar with this concept, or is it as much a surprise to you as it is to Max?
As a young lad, I played with conventional magnets. The fact that some materials were magnetic and others weren’t -- along with the fact that some materials could be used to form permanent magnets -- didn’t really surprise me; I just took it that this was the way things were.
Come to think of it, I still don’t really understand what magnetism is at its most fundamental level, but I'll worry about that when I have some spare time.
As a grew older, I started to learn about electromagnetic fields and effects. Just to make sure we're all tap-dancing to the same set of drums, let's briefly remind ourselves that a difference in electrical potential across two ends of a conducting wire causes current to flow, and current flowing through a wire causes an electromagnetic field to be generated around that wire.
Correspondingly, if a piece of wire is moved through an externally generated electromagnetic field, it cuts the lines of electromagnetic flux, resulting in an electrical potential being generated across the two ends of the wire.
We sometimes make use of components called inductors, which may be formed by winding a wire into a coil around a rod of iron or some other ferromagnetic material (the wire will be coated by a layer of insulating material to prevent coil windings forming electrical connections with each other or with the rod). When a current is passed through the coil, the result is an intense electromagnetic field.
Once again, I just accepted all of this as being just the way things were. Until now, I've never really stopped to think about how all of this comes to be at the most fundamental levels.
I'm sure you are familiar with some of the surprises that were revealed by Einstein's theories of relativity, such as the fact that space and time are "entwined" in a spacetime continuum, and that the faster you go (with reference to someone or something else), the less time passes for you (again, with reference to someone else).
This leads to relativistic phenomena that form the heart of many science fiction stories, such as Time for the Stars by Robert Heinlein. This tale features two identical brothers: Pat, who stays at home on Earth, and Tom, who travels to the stars on a spaceship that approaches the speed of light. When Tom returns, he's still a young lad, while Pat has grown into a crusty old man.
The reason I mention this here is that I just saw this video, which made me gasp in astonishment.
According to this video, electromagnetism is a relativistic phenomenon. Well, color me dumbfounded and call me a banana (thereby providing the opening to link to my banana slicer column). I had no idea about any of this. Were you already familiar with this concept, or is it as much a surprise to you as it is to me?