Mun
The Mun is Eurth's only natural satellite. It orbits at an average distance of about 384,400km (238,900mi), which is about 30 times the diameter of Eurth. Tidal forces between Eurth and the Mun have syncronized the Mun's orbital period (the munar month) with its rotation period (the munar day) which is at about 29.5 Eurth days, causing the same side of the Moon to always face the Eurth. The Mun's gravitational pull and - to a lesser extent, the San's - are the main drivers of Eurth's tides, making the Mun fundamental to much of Eurth's life. In geophysical terms, the Mun is a planetary object, or a satellite planet. Its mass is only 1.2% that of Eurth, and its diameter is 3,474km (2,159mi), this being roughly 25% of Eurth's (about as wide as Azania from Musha to the Northernmost post of Yien). Within the Sanar System, it is the largest and most massive satellite in relation its planet, the xth largest and most(?) massive moon overall, and larger and more massive than all known dwarf planets. Its surface gravity is about one sixth of Eurth's, and about half of that of Marz, and the xth highest among all the Sanar System moons. The body of the Mun is differentiated and terrestrial. The Mun has no significant hydrosphere. The Mun also lacks any atmosphere or magnetic field. It formed approximately 4.5 Billion years ago, not long after Eurth's formation. Despite heavy scientific debate, the leading theory proposes that the Mun formed out of the debris from a giant impact between Eurth and a supposed Marz-sized body called Theiu. The munar surface is covered in munar dust and is marked by large mountains, numerous impact craters, their ejections, ray-like streaks, rilles, and mostly on the near side of the Mun, by dark maria (seas), which are in reality giant plains of cooled magma. These seas were formed when molten lava flowed into ancient impact basins. The Mun is, with exception to when passing through Eurth's shadow during a munar eclipse, always illuminated by the San, but from Eurth the visible illumination shifts during its orbit, producing the famous munar phases. The Mun is the brightest celestial object in Eurth's nighttime sky. This is mainly due to its large angular diameter, while the reflectance of the munar surface is comparable to that of asphalt on Eurth. The apparent size to the naked eye is nearly the same as that of the San, allowing it to cover the San completely during a total Sanar eclipse. From Eurth, about 60% of the Munar surface is visible over time due to the cyclical shifts in perspective known as libration, making parts of the far side of the Mun visible. The Mun has been an important source of inspiration and knowledge for humanity, having been crucial to cosmography, mythology, religion, art, time keeping, natural science, and spaceflight.
