Does the moon affect sea levels?

The moon significantly influences sea levels through its gravitational pull, which causes the phenomenon known as tides. Tides are the periodic rise and fall of sea levels caused by the gravitational forces exerted by the moon and, to a lesser extent, the sun, as well as the rotation of the Earth. The gravitational attraction of the moon creates two high tides and two low tides each day as the Earth rotates.

When the moon is directly overhead or on the opposite side of the Earth (at full moon or new moon), its gravitational pull on the oceans is strongest, resulting in higher high tides, known as spring tides. Conversely, when the moon is at a right angle to the Earth (at first or third quarter moon), its gravitational pull on the oceans is weaker, resulting in lower high tides, known as neap tides.

In addition to the moon's influence, the sun also contributes to the tides, albeit to a lesser extent due to its greater distance from the Earth. When the gravitational forces of the sun and moon align, such as during new and full moons, the combined effect results in higher high tides and lower low tides, known as spring tides. When the gravitational forces of the sun and moon are perpendicular to each other, such as during first and third quarter moons, the effect is minimized, resulting in lower high tides and higher low tides, known as neap tides.

Overall, the gravitational pull of the moon is the primary driver of tides, which in turn affects sea levels along coastlines worldwide.