Earth referred to as "moons", after Earth's. The gravitational attraction between Earth and the Moon causes tides on Earth. The same effect on the Moon has led to its tidal locking: its rotation period is the same as the time it takes to orbit Earth. As a result, it always presents the same face to the planet. As the Moon orbits Earth, different parts of its face are illuminated by the Sun, leading to the lunar phases; the dark part of the face is separated from the light part by the solar terminator. Due to their tidal interaction, the Moon recedes
Sun and Moon (Middle-earth) for the Moon was the Silver Flower, and Gollum referred to it as the White Face. The Moon was more highly valued than the Sun by the Elves, both because it came from the Elder Tree, and because it rose first. In the universe of Middle-earth, the Moon was generally regarded as masculine, in recognition of Tilion. This gender corresponds with Máni, the personified moon in Norse mythology. In the early versions of "The Silmarillion" as described in "The Book of Lost Tales 1", a part of The History of Middle-earth series, the Sun was described in great detail as