Earth tide Earth tide Earth tide (also known as solid Earth tide, crustal tide, body tide, bodily tide or land tide) is the displacement of the solid earth's surface caused by the gravity of the Moon and Sun. Its main component has meter-level amplitude at periods of about 12 hours and longer. The largest body tide constituents are semi-diurnal, but there are also significant diurnal, semi-annual, and fortnightly contributions. Though the gravitational forcing causing earth tides and ocean tides is the same, the responses are quite different. The larger of the periodic gravitational forces is from the Moon but that of the
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