Answer: Tidal friction, caused by the gravitational interaction between the Earth and the moon, is responsible for both the moon's gradual drift away from the Earth and the slowing down of Earth's rotation.
Step-by-step explanation:
The moon's slowly drifting farther away from the Earth and the gradual slowing down of Earth's rotation are both caused by the phenomenon known as tidal friction. Tidal friction occurs due to the gravitational interaction between the Earth and the moon.
1. The gravitational force between the Earth and the moon causes tides to form on Earth's surface.
2. As the moon orbits the Earth, its gravitational force creates a bulge on the side of the Earth facing the moon, as well as a bulge on the opposite side.
3. The Earth's rotation carries these tidal bulges around the planet, resulting in two tidal "bumps" moving across the Earth's surface.
4. However, the rotation of the Earth causes a slight time delay between the position of the tidal bulge and the moon's gravitational force. This time delay creates a gravitational interaction between the tidal bulges and the moon's gravitational pull.
5. As a result, the gravitational interaction transfers some of the Earth's rotational energy to the moon's orbital energy.
6. This transfer of energy causes the moon's orbit to gradually increase, causing it to move farther away from the Earth at a rate of about 3.8 centimeters (1.5 inches) per year.
7. Additionally, the transfer of rotational energy to the moon's orbit leads to a gradual slowdown of Earth's rotation. This means that each day becomes slightly longer over time.