Space (Years 6–11) — Science

Right now you are hurtling through space at tens of thousands of miles per hour, riding a giant rock that loops endlessly around a burning ball of gas. That rock is Earth, the ball of gas is the Sun, and the invisible leash holding it all together is gravity.

Why this matters: Understanding the Solar System explains day and night, the seasons, eclipses, and how satellites and space missions work. It also shows how one simple force — gravity — shapes everything from a falling apple to the orbit of a whole planet.

Gravity keeps the planets in orbit around the Sun

The Solar System

Eight planets, Mercury → Neptune (not to scale): "My Very Easy Method Just Speeds Up Naming".

Our Solar System is the Sun and everything held by its gravity. At the centre sits the Sun — which is a star, a huge ball of hot glowing gas that makes its own light and heat. Around it orbit eight planets. In order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Mercury is the closest; we live on the third, Earth.

Stars, planets and moons

A moon orbits a planet, a planet orbits a star; only the star makes its own light.

It is easy to muddle these three, so line them up:

A star (like the Sun) makes its own light and heat.
A planet orbits a star and does not make its own light — it only reflects the star's light.
A moon (a natural satellite) orbits a planet. Earth has one Moon; Jupiter has dozens.

Object	Orbits what?	Own light?
Star (Sun)	Nothing (centre)	Yes
Planet	A star	No (reflects)
Moon	A planet	No (reflects)

Gravity: the invisible leash

Gravity is the "string": it pulls inward so the planet curves instead of flying off.

Every object with mass pulls on every other object — that pull is gravity. The Sun is so massive that its gravity reaches out across billions of miles and keeps the planets curving around it instead of flying off in a straight line. In the same way, a planet's gravity keeps its moons in orbit. Imagine whirling a ball on a string around your head: the string is gravity, constantly tugging the ball inward so it circles instead of shooting away. Cut the string and the ball flies off — cut gravity and the planets would too.

Stars themselves are born from vast clouds of gas and dust called nebulae, pulled together — again by gravity — until they grow hot enough to shine.

Worked reasoning. "Why doesn't the Moon just fly off into space?" Think in two parts. The Moon is moving sideways very fast, which alone would send it off in a straight line. But Earth's gravity constantly pulls it towards Earth. The two effects combine so the Moon keeps curving around us in a near-circle — a permanent orbit. Whenever you see the word "orbit", the answer almost always involves gravity providing the inward pull.

Common mix-up: The Sun is a star, not a planet — it only looks different because it is so close. And there is no "up" or "down" in space pulling planets: gravity is a pull between masses, always towards the massive object, not a downward force like on Earth's surface.

Memory hook: for the eight planets — "My Very Easy Method Just Speeds Up Naming" (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune). And remember: gravity is the string that keeps everything circling.