1 What Causes Tides?

It has been known for thousands of years that the waters of coastal seas ebb and flow on a daily basis. This oscillation is widely thought to be from the gravitational pulls of the Moon and Sun. Here we propose that, the Earth’s curved motions about the centre of mass of the Earth-Moon system and about the Sun may generate centrifugal effect to stretch the Earth’s body along the direction of equator; the majority of the Earth’s surface is covered with water, this makes the Earth look like being submerged in the water; the deformed Earth, together with the Earth’s daily rotation, makes the Earth’s each part regularly rise from and fall into the water. The rise and fall of related part result in the fall and rise of water level.