How did Isaac Newton use gravity to explain the tides?

Isaac Newton demonstrated that ocean tides are a direct consequence of his universal law of gravitation. By applying his gravitational theory, he showed that these phenomena—which had long mystified thinkers—are caused specifically by the gravitational pull exerted on Earth by the Moon and, to a lesser extent, the Sun.1

While Newton established the fundamental link between gravity and tidal motion, the complex details of these phenomena were not fully understood until much later. Modern science further explains that the Moon's gravitational field varies across Earth's surface, causing water to accumulate on the side facing the Moon and on the opposite side, resulting in the rhythmic rise and fall of the tides.12