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Seasons & Ecliptic (NAAP)
NAAP seasons lab: Earth's axis stays tilted 23.5° as it orbits. The ecliptic is the Sun's apparent path — that is just our orbit seen from inside.
Before you start
NAAP version of the seasons story: Earth’s axis tilt stays pointed the same way while Earth orbits the Sun.
Key idea
The ecliptic is the Sun’s yearly path on the sky — it is just our orbit seen from inside. Distance to the Sun is not why we have seasons.
What you see
- Earth on an orbit with a tilted axis
- Day-of-year and latitude sliders
- Hong Kong preset
Try this
- Set latitude to Hong Kong and step through June vs December
- Toggle the ecliptic overlay
- Compare with the ClassAction Seasons and Ecliptic lab
Why it matters in Hong Kong
At 22.3°N Hong Kong never has polar night; days stay between about 10.5 and 13.5 hours.
Common mistakes
- Blaming seasons on Earth being closer in summer (perihelion is in January)
Glossary
- Ecliptic
- Plane of Earth’s orbit; the Sun’s apparent yearly path.
- Obliquity
- 23.5° tilt of Earth’s axis.