Hello people, as the title says, I want to know if light can be closed in a mirror's box. My idea is, build a sealed mirror's box (The mirrors must reflect the 100% of the light), in that any light particle can escape, later turn on a light inside for 5 seconds and then turn it off (Let's suppose that the light source is "invisible" to make that the light can't be abosrbed for anything). So if I do that... Will the light be closed forever, bouncing against the walls? Or it will gradually start l