Answer:
The orbit of the Earth
Explanation:
It is widely speculated that orbital mechanics were responsible for the period of lushness that the Sahara desert and Northern Africa lived only 6000 years ago. Due to the changes in the Earth's orbit around the Sun, it is thought that the monsoon effect (season variations in wind patterns that produce a heavy rainy season) was more pronounced across the northern latitudes and resulted in the Sahara being much wetter than it is today.
Ocean tides are the result of differences in the gravitational force between
the sun and the Earth's near side and far side, and ditto for the moon.
Because of Earth's axial tilt (obliquity), our planet orbits the Sun on a slant which means different areas of Earth point toward or away from the Sun at different times of the year. Around the June solstice, the North Pole is tilted toward the Sun and the Northern Hemisphere gets more of the Sun's direct rays.
