# Earth's axial tilt and seasons

On the left animation, the inclination of the terrestrial axis of 23.4° is maintained. But because of its revolution around the Sun, the Earth turns a different part of its exposed surface forwards, which causes variations of sunlight during the year, and so the cyclical sequence of the seasons. The animation on the right shows the Earth on the side where it is illuminated. In yellow, the solar declination line oscillates between the Tropic of Cancer (at latitude 23.4° North) in the northern hemisphere and the Tropic of Capricorn (at latitude 23.4° South) in the southern hemisphere. Along that line, the solar radiation is optimal at every moment of the day, reaching its maximum when the sun is oriented due south.

- Kind: Short
- Year: 2025
- Runtime: 1 min
- By: Le Grand Quadrille
- Archive: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Earth%27s_axial_tilt_and_seasons.webm)
- Licence or status: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0) (as the archive states it)
- Credit: Le Grand Quadrille
- Who can watch: Teens profiles and older (the archive gives no rating; placed by Invisible Network from its collection and subjects)

[Watch now](https://invisiblenetwork.ai/watch/archive/commons/158801804?play=1)