Geography Topic
Components of the solar system
- Read notes
- Flashcards
- Quiz
- Confident
Study focus - 3 things
- The Sun is a STAR at the centre, not a planet — it holds everything in orbit
- The 8 planets in order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
- Other bodies: moons, dwarf planets, asteroids, comets — each defined by what it does and where it sits
Section 1What the solar system is
The solar system is the Sun and every body bound to it by gravity: the 8 planets, their moons, dwarf planets, asteroids, comets, and meteoroids. Everything orbits the Sun, directly or indirectly.
Section 2The Sun at the centre
The Sun is a star — a massive ball of plasma producing light and heat through nuclear fusion. It contains about 99.8% of the solar system's total mass, which is why its gravity holds everything else in orbit.
Section 3The 8 planets
In order from the Sun: Mercury, Venus, Earth, Mars (the four inner rocky planets), then Jupiter, Saturn, Uranus, Neptune (the four outer gas/ice giants). Memory aid: "My Very Educated Mother Just Served Us Nachos."
Section 4The other bodies
Moons orbit planets. Dwarf planets (Pluto, Ceres, Eris) are round but haven't cleared their orbital paths — that's why Pluto was reclassified in 2006. Asteroids are rocky, mostly in the asteroid belt between Mars and Jupiter. Comets are icy, and grow glowing tails when they pass close to the Sun.
Examples
Earth sits between which two planets?
Earth is the 3rd planet from the Sun. Venus is closer to the Sun; Mars is further out. So: Venus → Earth → Mars.
Why was Pluto reclassified from "planet" to "dwarf planet" in 2006?
Pluto is round and orbits the Sun, but it hasn't cleared its orbital path of other debris. "Clearing the path" is one of the three rules for being called a planet, so Pluto was reclassified as a dwarf planet.
Now let's water it
Session runs notes to flashcards to quiz back-to-back.