Gravity of Earth or (). Gravitational acceleration contributes to the total gravity acceleration, but other factors, such as the rotation of Earth, also contribute, and, therefore, affect the weight of the object. Gravity does not normally include the gravitational pull of the Moon and Sun, which are accounted for in terms of tidal effects. It is a vector (physics) quantity, whose direction coincides with a plumb bob. A non-rotating perfect sphere of uniform mass density, or whose density varies solely with distance from the centre (spherical symmetry), would produce a gravitational field of uniform magnitude at all points on its surface. The Earth
Sun and Moon (Middle-earth) an immense island of fire. The Moon was described as an immense island of crystal. It was also said there that the youth Tilion, who guided the Moon, was said to secretly be in love with Arien, the maiden who guided the Sun, and that because he steered the Moon too close to the Sun the Moon was burned, causing the darker spots on the Moon (the Lunar maria). Aulë devised "vírin", a crystalline material from which he made a cup wherein the flower was set. The markings on the moon are caused as Lórien tried to pluck the "Rose