The Solar System Flashcards – Cambridge IGCSE (9–1) Physics 0972 (Extended) (2026–2028)

What is the Solar System’s star?

The Sun.

What are the eight planets in order of increasing distance from the Sun?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

What are two types of minor planet that orbit the Sun?

Dwarf planets and asteroids.

What type of Solar System body is Pluto?

A dwarf planet.

Where are many asteroids found?

In the asteroid belt.

What are comets?

Smaller Solar System bodies that orbit the Sun.

What do moons orbit, and can other natural satellites orbit different bodies?

Moons are natural satellites that orbit planets. Natural satellites can also orbit other bodies.

What did the Solar System form from?

A rotating interstellar cloud of gas and dust containing many elements.

How did an accretion disc form around the developing Sun?

Gravity drew material together, and the rotating material formed a disc.

How did planets form within the accretion disc?

Material accumulated into larger bodies, eventually forming planets.

Which four planets are nearest the Sun, and what are their shared characteristics?

Mercury, Venus, Earth and Mars are comparatively small and rocky.

Which four planets are the outer planets, and what are their shared characteristics?

Jupiter, Saturn, Uranus and Neptune are comparatively large and rich in gaseous or volatile material.

How did conditions in the hot inner accretion disc affect rocky and volatile materials?

Rocky materials could form solids, while many volatile substances remained gaseous.

How did cooler conditions in the outer accretion disc affect planet formation?

More material could accumulate, helping outer planets grow larger and retain substantial gas and other volatile substances.

What force does a planet’s gravitational field exert on objects with mass?

An attractive gravitational force.

What is gravitational field strength at a position?

The gravitational force per unit mass at that position.

Which two properties of a planet determine its surface gravitational field strength?

Its mass and radius.

For planets with the same radius, how does mass affect surface gravitational field strength?

A more massive planet has a stronger surface gravitational field.

How does gravitational field strength change with increasing distance from a planet?

It decreases.

Where is most of the Solar System’s mass located?

In the Sun.

How does the Sun’s gravity keep a body in orbit around it?

It continually changes the direction of the body’s motion.

What two factors together determine a body’s orbit around the Sun?

The body’s motion and the Sun’s gravitational attraction.