Revolution
As the Earth moves around the sun, there is a point where it comes very near the sun. This point is called perihelion. Earth is closest to the sun at the beginning of January. At the perihelion, the Northern Hemisphere points away from the sun and receives less heat and light than during the rest of the year, while the Southern Hemisphere receives more heat and light than usual.
Aphelion
As Earth continues to move around the sun, there is a point where it is farthest from the sun. This point is called aphelion. During aphelion, the Northern Hemisphere points toward the sun, allowing Earth to receive large amounts of energy, making its temperature warm. The Southern Hemisphere points away from the sun, receiving less heat that makes the temperature low.
