What kind of wave is light?
Maxwell showed it is an electromagnetic wave
But what does it travel through?
Other waves we know are moving patterns in some material
- Sound in air
- Surface waves on water
- Waves on a string
What is the medium that transmits light?
Maxwell proposed the ether - mysterious substance in all space invented to carry light
Yet somehow the earth could move through it with no resistance!
Not a satisfactory state of affairs!