I’m preparing some notes for my graduate Electromagnetism class, and I’ve finally arrived at the section on Special Relativity. We will end up discovering the fully covariant formalism of the equations of electromagnetism in a few lectures, and a number of mysterious things we’ve seen over the course of the semester will be more natural in this setting, showing how marvellously Maxwell’s equations from the 19th Century, unifying Electricity and Magnetism, actually herald (actually should out loudly for!) Einstein’s 20th Century physics – Special Relativity.
But first I must review Special Relativity, going back to the basic thought experiments I like to talk about that lead you to discover it. Traditionally this means lots of scenarios involving flashes of light, and long extended objects being boosted at speed in various directions and so forth… All very fun.
Well, over the years I’ve changed the characters in the scenarios a couple of times, and now I’ve firmly (as of 2012) left Harry, his broom, Hermione, and the Quidditch game behind in favour of (the much preferred) Bilbo Baggins, the fire-drake Smaug, and Balin, son of Fundin. (Yes, I know that Bilbo never rode Smaug, and that Smaug (or Harry, even if riding his Firebolt) probably did not move at relativistic speeds…) You can see more about this in my post (“Evolution of a Poor Joke”) from 2012. I’ll just post the picture from then…
This all helps derive Lorentz-Fitzgerald contraction, in case you’re wondering. Ok, back to my notes.
-cvj
