Ocean tides are primarily caused by the gravitational pull of the Moon on Earth's oceans, with the Sun also contributing to a lesser extent. The Moon's gravity creates a tidal force that causes the water on the side of Earth closest to the Moon to bulge outward, forming a high tide. Simultaneously, on the opposite side of Earth, another high tide bulge forms due to the centrifugal force of the Earth-Moon system's rotation around their common center of mass. As Earth rotates, different regions pass through these bulges, experiencing two high tides and two low tides approximately every 24 hours
. The Sun, despite being much more massive than the Moon, is much farther away, so its tidal effect is about half that of the Moon. The combined gravitational forces of the Moon and Sun, along with Earth's rotation and the shape of coastlines, influence the timing and height of tides
. In summary, ocean tides result from:
- The Moon's gravitational pull creating two tidal bulges on opposite sides of Earth.
- The centrifugal force from the Earth-Moon system's rotation causing the bulge opposite the Moon.
- Earth's rotation moving locations through these bulges, causing the regular rise and fall of sea levels.
- The Sun's gravitational influence modifying the tides but to a lesser degree than the Moon
