How can a full moon be seen south of an observer's location?

Question

I know this seems like a simple question, but I'm trying to debate with a flat earth theorist. I asked him to explain why can the ISS visibly be seen orbiting the Earth with the naked eye, and he put this question to me instead.He asked: > "How can a full moon be observed south of an observer's location, despite the fact that if the moon is illuminated by the sun, an observer has to be almost directly between the sun and the moon to observe a full moon?"

Answer 1

The moon is far enough away that being south of the observers location can still see the full moon because the earth is not in the shadow.

Everyone sees the same phases of the Moon, but people south of the equator who face North to see the Moon when it is high in the sky will see the Moon upside down so that the reverse side is lit. The Moon goes around the Earth in a single day.

Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth – a situation known as synchronous rotation, or tidal locking. The Moon is directly illuminated by the Sun, and the cyclically varying viewing conditions cause the lunar phases.