As Earth moves, its axis always points in the same direction in space.
You could model Earth’s orbit by moving your right fist in a circle on
a desktop. You would need to point your thumb toward your left
shoulder and keep it pointing that way while moving your hand
around the desktop.
Earth’s orbit is not quite a perfect circle. In January, Earth is about
5 million kilometers closer to the Sun than it is in July. You may be
surprised to learn that this distance makes only a tiny difference in
temperatures on Earth. However, the combination of Earth’s motion
around the Sun with the tilt of Earth’s axis does cause important
changes of temperature. Turn the page to find out how.