Part 6/8:
Without light, the universe would be radically different. Not only would we be deprived of vision, but the fundamental properties that allow life to exist would cease to function. Atoms themselves rely on electromagnetic interactions; without light, there would be no atoms, leading to the absence of matter as we understand it—cars, houses, and even humans would not exist.
Interestingly, while we might daydream about the possibility of a universe that lacks electromagnetic forces, the absence of light would produce an unrecognizable cosmos, even if fundamental forces like gravity and the strong nuclear force could still exist.