The main cause of tides on Earth is the gravitational pull of the moon and, to a lesser extent, the sun. As the moon orbits the Earth, its gravitational force attracts the water in the oceans, creating bulges or high tides in the areas closest to the moon. Simultaneously, the areas on the opposite side of the Earth experience high tides due to the centrifugal force generated by the Earth's rotation. The sun also plays a role in tides, with its gravity contributing to the overall tidal patterns. Tides are cyclical, influenced by the positions of the moon and sun, resulting in the predictable rise and fall of sea levels.