This key facts covers Structure of Our Solar System within Our Solar System for GCSE Physics. Revise Our Solar System in Space Physics for GCSE Physics with 14 exam-style questions and 12 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 8 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📚 Structure of Our Solar System
The Sun:
- A main sequence star — fusing hydrogen into helium
- Contains 99.8% of the solar system's mass
- Diameter: ~1.4 million km (109× Earth)
- Surface temperature: ~5,500°C; Core: ~15 million°C
The Planets (in order from Sun):
| Planet | Type | Key Features | Orbital Period |
|---|---|---|---|
| Mercury | Rocky | Smallest, no atmosphere, extreme temperatures | 88 days |
| Venus | Rocky | Hottest (greenhouse effect), rotates backwards | 225 days |
| Earth | Rocky | Liquid water, life, 1 moon | 365 days |
| Mars | Rocky | Red planet, thin atmosphere, 2 moons | 687 days |
| Jupiter | Gas giant | Largest, Great Red Spot, 95+ moons | 12 years |
| Saturn | Gas giant | Spectacular rings, 146+ moons | 29 years |
| Uranus | Ice giant | Tilted on side, blue-green colour | 84 years |
| Neptune | Ice giant | Furthest, strongest winds, blue colour | 165 years |
💡 Memory trick: My Very Educated Mother Just Served Us Nachos
Practice questions for Our Solar System
Which of the following is NOT an inner rocky planet in our solar system?
Explain how gravity keeps a planet in a circular orbit around the Sun.
Quick recall flashcards
What is a light year?
The distance light travels in one year = 9.46 × 10¹² km. It's a DISTANCE, not a time!
What is a dwarf planet?
A planet-like object that is too small to clear its orbital path. Examples: Pluto, Ceres, Eris