Tides occur in oceans and seas due to which of the following?

1. Gravitational Force of the Sun.

2. Gravitational Force of the Moon.

3. Gravitational Force of the Earth.

Select the correct Answer using the code given below:

The correct answer is 1, 2 and 3.

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun, and the rotation of the Earth (which involves the gravitational force of the Earth keeping the water body adhered to it while centrifugal forces and gravitational gradients act upon it).

Let us break down how each force contributes to the occurrence of tides:
1. Gravitational Force of the Moon: The Moon is the primary driver of ocean tides. Because the Moon is much closer to the Earth than the Sun, its gravitational pull exerts a stronger tidal force on the Earth's oceans. This pull creates a bulge of water on the side of the Earth facing the Moon, as well as a corresponding bulge on the opposite side due to centrifugal forces, resulting in high tides.
2. Gravitational Force of the Sun: Although the Sun is much more massive than the Moon, it is also much farther away. Consequently, its tide-generating force is about 46% of that of the Moon. However, it still plays a significant role. When the Sun, Moon, and Earth align (during new moon and full moon), their gravitational forces combine to produce exceptionally high tides known as spring tides. When they are at right angles, they counteract each other slightly, leading to lower-than-average tides known as neap tides.
3. Gravitational Force of the Earth: The Earth's own gravity is essential for the existence of tides. Earth's gravity acts as the restoring force that holds the oceans to the planet. The balance between the Earth's gravitational attraction (which pulls the water inward) and the external gravitational pulls of the Moon and Sun (which pull the water outward, creating a gradient) is what allows the tidal bulges to form and move as the Earth rotates.

Therefore, all three gravitational forces—of the Sun, the Moon, and the Earth—are fundamental to the mechanism of ocean tides, making option "1, 2 and 3" the correct choice.