Tide
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Tides are the periodic rise and fall of sea level resulting from the differential gravitational forces exerted primarily by the Moon and the Sun, combined with inertial effects associated with the Ear
In Maine (U.S.), low tide occurs roughly at moonrise and high tide with a high Moon, corresponding to the simple gravity model of two tidal bulges; at most places however, the Moon and tides have a phase shift.
Low tide at Bangchuidao scenic area, Dalian, Liaoning Province, China
Low tide at Ocean Beach in San Francisco, California, U.S.
Low tide at Bar Harbor, Maine, U.S. (2014)
Tidal force
Videos
The tidal force or tide-generating force is the difference in gravitational attraction between different points in a gravitational field. It causes different parts of bodies to be pulled unevenly, so
Tide
…effects associated with the Earth–Moon system’s orbital motion and the Earth's rotation. While these astronomical forcings generate the fundamental tidal potential, actual observed tides are strongly modified by terrestrial factors, including the geometry of ocean basins, continental boundaries, bathymetry, the…
Figure 4: Saturn's rings are inside the orbits of its principal moons. Tidal forces oppose gravitational coalescence of the material in the rings to form moons.
Figure 5: Comet Shoemaker-Levy 9 in 1994 after breaking up under the influence of Jupiter's tidal forces during a previous pass in 1992.
Figure 7: Tidal force is responsible for the merge of galactic pair MRK 1034.