Stardust Primary Color

"Before the atmosphere and oceans were formed, the earth was once a gray sphere rotating in space. Just like the moon looks like now: the sun's ultraviolet rays hit the moon without any cover, and the colors were destroyed; for this reason, the rocks on the moon's surface are not as colorful as on the earth, but monotonous and dead gray. Therefore, the colorful colors on the earth's surface should be thanked for the atmosphere, which filters out these deadly ultraviolet rays." - Italo Calvino "Colorless World"