How to Play

🌞 Start the Dance

Press Play to set the Earth circling the Sun and the Moon orbiting Earth. Immediately you’ll see how sunlight creates a bright hemisphere and a shadowed hemisphere on each body. The Earth’s spinning day/night line updates in real time, and the Moon’s illuminated side always turns toward the Sun.

⏳ Adjust Time

Use the Speed slider to glide slowly through special moments or fast-forward through several months. You can pause at any time to freeze the configuration, then scrub gently along the timeline to inspect Moon phases or study an eclipse from multiple angles.

🔍 Compare Views

For every moment you explore, you can match the cause (in the orbit diagram) with the effect. Pause the system, examine the geometry, then look at how the Sun and Moon appear. The view panels work together to build a complete picture.

Study Notes

☀️ Light, Shadow, and Illumination

Only sunlight shapes what we see. The Moon always has one sunlit half — phases occur because Earth’s viewpoint changes, not because the Moon’s light changes. The day–night line on Earth works the same way: whichever half faces the Sun experiences daylight.

🌘 From Phases to Eclipses

Phases shift smoothly as the Moon moves around Earth. A new moon occurs when the Moon is near the Sun; a full moon occurs when it’s opposite the Sun. Eclipses are far rarer: they require precise alignment so that one body’s shadow falls on another.

🌔 Learning Prompts

Try predicting what the next phase icon will be before it appears. Pause during a full moon and ask why a solar eclipse is impossible in that configuration. Use the orbit panel to explain what you see in the sky panel — the model becomes a story you can decode.

🔭 A Living Diagram

Sun-Earth-Moon Model is not a puzzle or challenge but a guided visual laboratory. By watching motion, pausing, rewinding, and comparing views, players build a natural intuition for how orbital geometry creates the rhythms of the sky.