4 DECEMBER: SOUTH TANGERANG, INDONESIA – Full moon as seen on 4 December 2017 in the sky in South Tangerang, Indonesia. A full moon is the lunar phase that 3occurs when the Moon is completely illuminated as seen from Earth. This occurs when Earth is located directly between the Sun and the Moon. This means that the hemisphere of the Moon that is facing Earth (the near side) is almost fully illuminated by the Sun and appears round (while the far side is almost completely unlit). A full moon occurs once every month. (Photo by Donal Husni/NurPhoto via Getty Images)