Part 1 of 5 · freeIntroduction
On Earth, summer and winter come mostly from the tilt of the axis, about 23.5°. The Sun beats down harder on one hemisphere, then on the other. The pattern feels obvious to us. In the solar system, it is really the mild version.
Every planet combines its own tilt with the shape of its orbit. The result: worlds with no seasons, others with extreme contrasts, and winters that run for decades.
The rest is in the Sophia app.The remaining parts, the open-book quiz and the full glossary. Free to start; Premium unlocks everything.
- 2Tilt, the engine of contrast
- 3When distance from the Sun counts too
- 4Venus, Mercury, Saturn: other rules
- 5Why Earth's seasons stay stable
Open-book quiz9 questions whose answers are in the text.
Glossary17 terms explained in a tap.
30 languagesThe same course, from French to Japanese.
