I've been reading an old discourse by an electrician at the turn of the 19th century, and he mentions "ether" quite a bit. I've done some reading around and apparently it was believed to be the medium through which electricity and light sent waves out through space. What I'm wondering is if there are any scientists today who believe in something like it, or if the belief really did die out with Einstein's theory of relativity. If the latter case is true, does anyone know of the last prominent scientists that pursued the theory? Just curious.