The Moon's Orbit
Know that the Moon orbits Earth approximately once a month, that it does not make its own light but reflects sunlight, and that its changing appearance (phases) is caused by how much of the sunlit side we can see from Earth
What a learner can do afterwards
- State that the Moon orbits Earth roughly once every 28-30 days
- Explain that the Moon reflects sunlight rather than producing its own light
- Describe how Moon phases happen: we see different amounts of the lit-up side as the Moon orbits Earth
The lesson
The Moon is always moving. It circles all the way around Earth about once a month, which takes about 28 to 30 days.
The Moon does not glow on its own. Sunlight bounces off it, the same way light bounces off a mirror or a shiny ball, and that bounced light is what you see.
You already know the Moon can look like a full circle, a half circle, or a thin sliver. That happens because the Moon keeps orbiting Earth. As it moves, sunlight lights up a different part of the side facing you, so the shape you see keeps changing.
The whole Moon is round every single night. You are only seeing the part that is both facing Earth and lit up by the Sun.
The Moon orbits Earth about once a month, always shines by reflecting sunlight, and its changing shape comes from how much of that sunlit side we can see.
Watch it
Where it sits
Learn first
This opens up
Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.