Lol It's the sphere earth that casts the shadow, the light comes from the sun. The lesser light is buried under earth and rock for ever in darkness until it's no more, if you pealed away the outer layers of earth the core would look like a red dwarf sun glowing bright. without either the sun or the core of earth there would be no life on earth. indeed very few can take such a leap of faith, probably none but me which is fine with me for I'm quite comfortable in that way. indeed the great light is the sun in the middle of our solar system.