From Final Fantasy Wiki

The Moon

"A world of monsters. Many works of art and epics about the moon throughout history are evidence of its mystical powers."

—FFVIII Info Corner

The Moon is an important story element in Final Fantasy VIII. All monsters in Final Fantasy VIII come from the Moon, brought over to Earth during the event known as the Lunar Cry. It is possible that this happens when the Moon is in its closest position to Earth. The Crystal Pillar is also believed to have come from the Moon.

Esthar's Lunar Base is located close to the Moon, as well as Adel's Tomb. The spaceship Ragnarok is also found here.