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
1 · Read
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.
More to read
Key points: The moon and its motions
The Moon is Earth's constant companion. It orbits our planet about once every 27.3 days. As it travels around us, the Sun lights up different parts of the side facing us. This creates the Moon phases we see: new moon, crescent, quarter, gibbous, and full moon. The Moon does not make its own light. It reflects sunlight like a mirror. The same side of the Moon always faces Earth because it spins once for each orbit. That is why we never see the far side from the ground.
Phases of the Moon: A Simple Scientific & Visual Guide
Have you noticed the Moon changes shape? It does not really change shape. We just see different amounts of its sunlit side. When the Moon is between Earth and the Sun, the dark side faces us. That is a new moon. As it moves, we see a sliver (crescent), then half (quarter), then most (gibbous), then the whole face (full moon). Then it shrinks back down. This cycle takes about 29.5 days from new moon to new moon. Farmers, sailors, and calendars have used these phases for thousands of years.
Types of lunar eclipses
Sometimes Earth gets right between the Sun and the Moon. Earth's shadow falls on the Moon. That is a lunar eclipse. It only happens at full moon. There are three kinds. A total lunar eclipse turns the Moon a spooky red because Earth's atmosphere bends sunlight around the edges. A partial eclipse bites a chunk out of the Moon. A penumbral eclipse is subtle. The Moon just dims a little as it passes through Earth's outer shadow. Lunar eclipses are safe to watch with your bare eyes.
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2 · Watch
به انگلیسیTake it off screen
Where it sits
Learn first
Optional connections
This opens up
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.