The moon enters phases depending on its orbit of the Earth; when the moon is completely illuminated by the Sun, we have a full moon. As EarthSky explains: “observers in the Northern and Southern Hemispheres see the moon apparently upside-down with respect to each other.”Understanding the gibbous moon is keyThe gibbous moon occurs on either side of the invisible new moon, making it either the waxing “D” or the waning “C” in the mnemonic device. The website Sciencing elaborates on how this works, and how it can be instructive in understanding how the moon generally operates:A gibbous moon is an almost complete moon, with a crescent of darkness covering one side of the moon. The gibbous moon’s light portion is slightly egg-shaped, and the gibbous moon comes on either side of the full moon. Basically, the moon’s phases take place over the course of a month and you can track the cycle by keeping tabs on the “DOC” device.

Source: The Nation April 22, 2021 20:07 UTC