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
Full moon and the names "harvest moon" and "hunter's moon" for the full moons of autumn. The "harvest moon" and "hunter's moon" are traditional terms for the full moons occurring during late summer and in the autumn, in the northern hemisphere usually in September and October respectively. The "harvest moon" is the full moon closest to the autumnal equinox (22 or 23 September), coming anywhere from two weeks before to two weeks after that date. The "hunter's moon" is the full moon following it. The names are recorded from the early 18th century. The "Oxford English Dictionary" entry for "harvest moon" cites