LEARN · PRACTISE · DISCOVER
The Giant Planets
Beyond Mars and the asteroid belt lie four enormous worlds: Jupiter, Saturn, Uranus and Neptune. They are called the giant planets. Unlike the rocky planets, they do not have solid surfaces to stand on. In this lesson you will explore these huge, faraway giants.
Gas giants: Jupiter and Saturn
Jupiter and Saturn are called gas giants because they are made mostly of the gases hydrogen and helium.
Jupiter: the king of the planets
Jupiter is the largest planet in the solar system. It is so big that all the other planets could fit inside it! Jupiter has colourful stripes made of clouds, and a giant storm called the Great Red Spot. This storm is bigger than Earth and has been raging for hundreds of years.
Jupiter has dozens of moons. Four of the biggest were discovered by the scientist Galileo more than 400 years ago. One of them, Ganymede, is the largest moon in the solar system, even bigger than the planet Mercury.
Saturn: the ringed planet
Saturn is famous for its beautiful rings. The rings are made of billions of pieces of ice and rock, from tiny grains to chunks as big as houses. All four giant planets have rings, but Saturn’s are by far the brightest and biggest.
Saturn also has many moons. Its largest moon, Titan, has a thick orange atmosphere and lakes of liquid methane.
Ice giants: Uranus and Neptune
Uranus and Neptune are called ice giants. They contain more water, ammonia and methane ices than the gas giants. The methane gas in their air makes them look blue or blue-green.
Uranus: the sideways planet
Uranus is tipped over on its side, so it seems to roll around the Sun like a ball. Scientists think a huge collision long ago may have knocked it over. Uranus is extremely cold.
Neptune: the windy planet
Neptune is the farthest planet from the Sun. It is dark, freezing and has the fastest winds in the solar system, much faster than any hurricane on Earth. Neptune takes about 165 Earth years to travel once around the Sun.
Comparing the giants
| Planet | Type | Special fact |
|---|---|---|
| Jupiter | gas giant | largest planet, Great Red Spot storm |
| Saturn | gas giant | biggest, brightest rings |
| Uranus | ice giant | spins on its side |
| Neptune | ice giant | farthest planet, fastest winds |
Example
Lily asked, “Could an astronaut land on Jupiter?” Her teacher explained that Jupiter has no solid ground. A spacecraft would sink deeper and deeper into thicker clouds until the crushing pressure and heat destroyed it. Scientists study the giants using robot spacecraft that fly past or orbit them instead.
Key takeaways
- The giant planets are Jupiter, Saturn, Uranus and Neptune.
- Jupiter and Saturn are gas giants; Uranus and Neptune are ice giants.
- Jupiter is the largest planet; Saturn has the brightest rings.
- Uranus spins on its side; Neptune is the farthest and windiest.
Practice
- Which is the largest planet?
- What are Saturn’s rings made of?
- Why do Uranus and Neptune look blue?
- Which planet is farthest from the Sun?
Answers: 1 is Jupiter. 2 is pieces of ice and rock. 3 is because of methane gas in their air. 4 is Neptune.