Earth's Tides Gravity is the key to the Earth's rising and falling tides. The combined gravitational effects of the Sun and the Moon constantly pull the world's oceans in different directions and create tidal effects. But there are several other factors that complicate this basic process. Friction, the Earth's rotation, the tilt of its axis and the gravitational pull given off by the Sun and Moon that affects Earth's atmosphere. These forces together conspire to …showed first 75 words of 630 total…

…showed last 75 words of 630 total…nearer the Earth. According to his calculations if the Moon were just one third of its present distance, the force would be 27 times greater. This implies that ocean tides would be so enormous that they would regularly swamp many of the world's lowland regions at every high tide. The tidal force would also be strong enough to cause parts of the earth's crust to flex up and down with the tides resulting in catastrophic earthquakes.