IGCSE 0625 / Section 6.1.2 / Core

The Sun and its family.

Around one ordinary star wheels a whole household: four small rocky worlds close in, four giants of gas further out, a belt of rubble between them, and comets that swing in from the cold and back out again.

The key idea

The Solar System contains the Sun and the objects orbiting it: eight planets, with the four inner ones small and rocky and the four outer ones large gas giants, plus moons, asteroids in a belt between Mars and Jupiter, and comets on long elliptical orbits.

Definition · learn the exact words

The Solar System is the Sun and everything orbiting it: eight planets, their moons, asteroids and comets.

inner 4: small and rocky · outer 4: large gas giants

The asteroid belt lies between Mars and Jupiter. Comets follow long, highly elliptical orbits.

Section 01

Tour the system.

Move out from the Sun past the rocky planets, the asteroid belt and the gas giants.

Stage 1 · Learn

Check the solar system

Four quick checks. Each correct answer earns XP and lights this skill on your star map.

Quick check+10 XP

The four inner planets of the Solar System are...

Quick check+10 XP

The four outer planets are...

Quick check+10 XP

The asteroid belt lies between...

Quick check+10 XP

A comet follows...

Section 02

Rocky in, giants out.

The inner planets are small and rocky, the outer ones large gas giants, with a belt of asteroids between.

Examiner trap

The asteroid belt lies between Mars and Jupiter, separating the rocky inner planets from the gas giants. Comets, unlike planets, follow very long, highly elliptical orbits rather than near-circular ones.

Stage 2 · Exam

Exam-style questions

Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.

Finish the four checks above to unlock the exam questions
Exam style+20 XP

Which correctly describes the planets of the Solar System?

Exam style+20 XP

A natural object that orbits a planet is called a...

Exam style+20 XP

How does a comet’s orbit differ from a planet’s?

Skill unlocked

The solar system, mastered.

The Solar System is mapped. Keep the chain going.

-Rank -Level -Score -Topics
Go deeper · practice
Six original Cambridge-style questions
The Sun, the rocky and gas-giant planets, moons, the asteroid belt and comets. Attempt each, then reveal the worked solution.
Stage 3 · master the unit
Space physics challenge
Mixed questions across the whole unit, each one worth XP. Start this only when you feel confident across every topic in the unit, not just the solar system.
Start the unit challenge →