Tides on Earth The gravitational forces of the Moon and the Sun deform the oceans. Due to Earth’s rapid rotation, the high tide closest to the Moon leads it around Earth by about 10°. (a) The greatest deformation (spring tides) occurs when the Sun, Earth, and the Moon are aligned with the Sun and the Moon either on the same or opposite sides of Earth. (b) The least deformation (neap tides) occurs when the Sun, Earth, and the Moon form a right angle.