Question

Why is there a tidal bulge on the opposite side of the Earth from the Moon?

a) Because of the Sun's gravity.
b) Because friction between the water and the ground drags the bulge raised by the Moon around to the far side of the Earth.
c) Because that side of the Earth feels less gravity from the Moon than the center of the Earth does.
d) Because the oceans are all attached, so that if you deform the oceans on one side of the Earth, the oceans on the other side deform, too.
e) Because the Moon's gravity pushes the water on that side of the Earth away from the surface.

Answer 1

The tidal bulge on the opposite side of the Earth from the Moon is created because Earth is pulled toward the Moon more than the water on the far side, due to the difference in gravitational pull by the Moon across Earth's diameter.

Step-by-step explanation:

The reason there is a tidal bulge on the opposite side of the Earth from the Moon is because of the gravitational interactions between the Earth and the Moon. Specifically, the correct answer to the question is (c) Because that side of the Earth feels less gravity from the Moon than the center of the Earth does.

This difference in gravitational pull causes the Earth to be pulled towards the Moon more than the water on the far side is, resulting in Earth being pulled away from that water and leading to a bulge. Since the Moon's gravity diminishes with distance, it exerts a weaker pull on the water on the far side than on the Earth itself, allowing the water to remain while Earth is drawn toward the Moon.

The tidal forces exerted by the Moon create two tidal bulges. One is due to the direct gravitational attraction on the side closer to the Moon; the other results from the weaker gravitational attraction on the far side. The actual flow of water over the Earth's surface towards these two areas, one below and one opposite the Moon, causes the water to pile up, creating the observed tidal bulges.