In 1845, Michael Faraday showed that light and magnetism are linked. He passed a beam through glass inside a magnetic field and found that its polarization — the direction its waves wiggle — rotated.

Today we celebrate the birthday of scientist Michael Faraday (1791-1867). What comes to mind when you think of Faraday? The Faraday cage, of course! But like many other 19th scientists generally ...