The quick answer
Eight planets travel around the Sun. In order they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The first four are small and rocky. The other four are giants made mostly of gas and ice.
TankiRanki, how many planets are there? I always muddle up the ones in the middle.
RankiThere are 8. And I know a trick that makes them easy to remember. Ready?
What is a solar system?
A solar system is a star with everything that travels around it. Our star is the Sun. Planets, moons, and comets all circle around it. Asteroids are big space rocks. Comets are balls of ice and dust.
A planet is a big, round world that travels around a star. Each planet has its own path, called an . Planets make no light of their own. We can see them because sunlight shines on them.
The four rocky planets
The four planets closest to the Sun are made of rock and metal. They have hard ground, a bit like the Earth. They are called the inner planets.
- Mercury is the smallest planet and the closest to the Sun.
- Venus is the hottest planet. Thick clouds trap its heat like a heavy blanket.
- Earth is our home, the only planet where we know there is life.
- Mars is red and dusty. Robot cars called drive around on it.
The four giants
Further out are four huge planets. Jupiter and Saturn are . They are made mostly of gas, and they have no solid ground to stand on.
Jupiter is the biggest planet of all. About 11 Earths would fit across it. It has a giant storm called the Great Red Spot, about as wide as our whole planet. Saturn has beautiful rings made mostly of ice.
Uranus and Neptune are called . They are very cold and very far away. Uranus spins on its side, like a ball rolling along. Neptune has the fastest winds of any planet we know.
TankiWait. What happened to Pluto? Wasn’t it a planet too?
RankiIt was, until 2006. Then scientists decided Pluto is a dwarf planet. It is small, and lots of other icy worlds share its part of space.
A trick to remember the order
Here is a sentence that helps. Each word starts with the same letter as a planet, in the right order from the Sun.
My Very Easy Method Just Speeds Up Naming. M is for Mercury, V for Venus, E for Earth and M for Mars. J is for Jupiter, S for Saturn, U for Uranus and N for Neptune.
Try it
Make a fruit model of the planets
You need
What to do
- Use the watermelon for Jupiter and the smaller melon for Saturn.
- Use the oranges for Uranus and Neptune.
- Use the grapes for Earth and Venus, the pea for Mars and the peppercorn for Mercury.
- Lay them in a line in the right order from the Sun, with a label for each.
- Guess how many grapes would fit across the watermelon. About 11 Earths fit across Jupiter.
TankiMy Very Easy Method Just Speeds Up Naming. I think I will never forget Neptune again.
RankiSay it three times fast, and the planets are yours forever!
Big words
- asteroids
- Big rocks that travel through space around the Sun.
- orbit
- The path a planet takes as it travels around the Sun.
- rovers
- Robot cars that drive around on another planet or a moon.
- gas giants
- Huge planets made mostly of gas, like Jupiter and Saturn.
- ice giants
- Very cold, big planets far from the Sun, like Uranus and Neptune.
- dwarf planet
- A round world that travels around the Sun but is too small to count as a planet.
Quick quiz
1. Which planet is the biggest?
Jupiter is the biggest planet. About 11 Earths would fit across it.
2. Which planet is the hottest?
Venus is the hottest, because its thick clouds trap the heat, even though Mercury is closer to the Sun.
3. What is Pluto called today?
Since 2006, scientists call Pluto a dwarf planet.
For parents and teachers
Since 2006 the International Astronomical Union defines a planet as a body that orbits the Sun, is round under its own gravity and has cleared its orbital neighbourhood, which Pluto has not. Children often remember the order better if they invent their own memory sentence, so it is worth making up a silly one together.
Pictures marked “AI generated” were made with AI tools. Ranki and Tanki are AI generated characters. Found a mistake? Write to info@pr-geo.com and we will fix it.
