The Moon, sometimes referred to by its Latin name Luna, is Earth's only natural satellite and the fifth largest natural satellite in the Solar System.
The Moon makes a complete orbit around the Earth every 27.3 days (the orbital period), and the periodic variations in the geometry of the Earth–Moon–Sun system are responsible for the lunar phases that repeat every 29.5 days (the synodic period). It is in synchronous rotation, meaning that it keeps nearly the same face turned toward the Earth at all times and so rotates on its axis every 27.3 days too.
Geochemical mapping from orbit implies that the crust of the Moon is largely anorthositic in composition, consistent with the magma ocean hypothesis. In terms of elements, the crust is composed primarily of oxygen, silicon, magnesium, iron, calcium, and aluminum. Based on geophysical techniques, its thickness is estimated to be on average about 50 km. Most of the Moon's mare basalts erupted during the Imbrian period 3.0–3.5 billion years ago. Nevertheless, some dated samples are as old as 4.2 billion years, and the youngest eruptions, based on the method of crater counting, are believed to have occurred only 1.2 billion years ago.
In ancient folklore, the moon was often blamed for certain forms of madness and other misfortunes, leading to terms like "lunacy" and "lunatic", and legends such as the werewolf.
The blood of murder victim Todor became a vurkolak, which plagued his native village of Gramada for a time. When the vurkolak attempted to devour the moon one night, the whole village produced as much noise as possible to drive it off. Finally, headman Symeon and his brother Rossen fired off their large guns. The noise frightened off the vurkolak.
In the alternate designated as 3477 by Crosstime Traffic, the German Empire achieved effective control of all Earth, it sent a man to the Moon in the middle of the 21st Century. The Germans then conducted a massive worldwide propaganda campaign presenting this as a proof of German ingenuity and science, superior to that of all other nations. They did not, however, feel that more Moon missions were worth the continued expense. Consequently, the first man on the Moon, who was still alive in 2096, would remain the only one for the foreseeable future.
Early in the 21st century, Japan staged a surprise attack on United Europe bases on Io using equipment from their Moon Base. After the initial missile attack, Japan landed a number of Luna equipped crawlers including two under the overall command of Sublieutenant Mitsuo Onishi, which pursued the crawler of Renée Messier and Alec Hall.
The Moon was important to the world of Faerie. Every month, on the night of the full moon, certain inanimate creatures such as garden gnomes came to life. They would revert to their non-living states at moonset, unless they awakened in a place of ancient magics, in which case they would remain alive.
David Goldfarb resented that the British had not gone there or had such a presence in space as the other leading powers did. He further resented the fact that a Nazi was the first man to set foot on the moon.
The United States had established several lunar bases: Moon Bases Alpha and Beta.