Tides are primarily caused by the moon's gravitational pull on Earth's oceans, which creates bulges of water on both the side closest to and farthest from the moon. The sun's gravity also contributes to tides, but to a lesser extent. The moon's gravity is the main driver of tides, especially when the moon and sun are aligned, resulting in higher tides during full and new moons.
Here's a more detailed explanation:
1. The Moon's Gravitational Influence:
The Moon's gravity exerts a differential force on Earth, pulling water towards it and creating a bulge on the side of Earth closest to the Moon.
Because of inertia, water also bulges out on the opposite side of Earth, away from the Moon.
These bulges are the high tides, and the areas between them are the low tides.
2. The Sun's Influence:
The Sun also has a gravitational effect on Earth's tides, but it's less powerful than the Moon's due to the Moon's closer proximity.
The Sun's gravitational pull contributes to higher tides during full and new moons, when the Sun, Earth, and Moon are aligned.
3. Spring Tides:
When the Sun, Earth, and Moon are aligned (during full and new moons), their gravitational forces combine, leading to higher high tides and lower low tides, called spring tides.
Spring tides are typically 20% higher than normal and occur twice a month, coinciding with the full and new moons.
4. Neap Tides:
When the Sun, Earth, and Moon form a right angle (during the first and third quarter moons), their gravitational forces partially cancel each other out, resulting in lower high tides and higher low tides, called neap tides.
5. Other Factors:
The shape of the Earth's coastlines and the depth of the ocean also influence tide patterns.
Tidal friction between the Moon and Earth is also slowly slowing down Earth's rotation.
