In this photo taken Dec. 27, 2018, the moon, in a waning gibbous phase and briefly visible on an otherwise cloudy day, is seen from Seattle. Despite the name of Pink Floyd's best-selling album, the side of the moon you can't see isn't always dark. But it is far. So scientists call the area where a Chinese spacecraft just landed the far side, not the dark side. (AP Photo/Elaine Thompson)