The earth is constantly in motion spinning on it's axis and revolving and orbiting around the sun. Circling the earth is the moon. Let's say the girl in yellow is the sun, and the man in blue is the earth, and grey for the moon.
Because of earth's orbit, we get our seasons. The winter and summer solstice occur on the longest, and shortest days of the year. We also have the spring and fall equinox when we have exactly twelve hours of day and night.
Our earth's place in space is still being discovered today! Space exploration is helping us learn more about the universe.