3-11: The Sun-Earth-Moon System

A. The Sun-Earth-Moon System

Earth has only one moon, but some planets have multiple moons. Jupiter has somewhere between 80 and 95 moons, Saturn has 146 moons, Uranus has 27, and Neptune has 14. This would be something to explore in greater detail if we were to move to outer space.

As Earth orbits the Sun, the Moon orbits Earth. The relationship between these objects is often called the Sun-Earth-Moon system. A system is a group of related things that work together as a whole. The diagram of the Sun-Earth-Moon system shows Earth’s orbit in blue and the Moon’s orbit in orange.

B. Make a Model

Ekta taught us that astronomers use models to help them better understand objects in our universe. Now it is your turn to create a model to help you better understand the Sun-Earth-Moon system.

Directions: Follow the directions in your Mission Log to create a Sun-Earth-Moon system model. Use this model to observe the moon’s orbit around Earth and the Earth’s orbit around the Sun.

C. Phases of the Moon

Have you ever noticed that the moon appears to change shape throughout the month? The pattern of these changes is called the phases of the moon. The moon doesn’t change, though. As Earth orbits the Sun and the moon orbits Earth, different amounts of sunlight reach the moon. The phase of the moon depends on where the moon is in its orbit.

Another interesting thing about the moon is that it helps to make Earth’s tilt stable. If we did not have the moon, we would be wobbling our way around the Sun, which could lead to unstable seasons and weather patterns.

What do you think it’s like to have more than one moon? How do you think many moons impact another planet like Jupiter?