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The Solar System

Map

Arrows point from what you learn first to what it opens. Point at a concept to light up its chain and where it comes back deeper. Right-click a concept (or press and hold it) for its lessons and stories.

  • Proven to depth123
  • Open
  • Locked
  • Comes back deeper
Giant planetsPlanetsRocky planetsSmall worldsThe EarthThe MoonThe SunThe size of the solar systemThe yearIn The SkyConstellationsIn The Sky

Learning path

In the order the concepts build on each other.

  1. PlanetsLockedThe planets are worlds that go around the Sun, like the Earth. From the Earth they look like bright stars that slowly wander across the constellations, and they shine with sunlight, not their own light. There are eight of them; in order from the Sun they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.Opens after: The year, Constellations
  2. The SunReadyThe Sun is a huge, hot, glowing ball, very far away. It gives us light and heat - when it is up it is day, and standing in its light feels warm.
  3. Rocky planetsLockedMercury, Venus, Earth and Mars, the four planets closest to the Sun, are small balls of rock and metal with solid ground. Mercury has almost no air and swings from very hot days to very cold nights; Venus's thick air traps heat and makes it the hottest planet; Mars is red, cold and dusty; the Earth is the only place we know of with life.Opens after: Planets
  4. The EarthLockedThe Earth is the huge ball we all live on - mountains, seas, forests and cities are all on it. It is so big that it looks flat to us, but from space you can see it is round. The Sun lights and warms it, one half at a time.Opens after: The Sun
  5. Giant planetsLockedJupiter, Saturn, Uranus and Neptune, the four planets farthest from the Sun, are giants made mostly of gas, with no solid ground. Jupiter is the biggest, about 11 times as wide as the Earth; Saturn has bright rings of ice and rock; Uranus is tipped on its side; Neptune is the farthest. All four have rings and many moons.Opens after: Rocky planets
  6. The MoonLockedThe Moon is a ball of rock that goes around the Earth about once a month and lights our nights. It makes no light of its own - moonlight is sunlight bounced off its rocks. Through a telescope you can see it is covered in craters and mountains.Opens after: The Earth
  7. Small worldsLockedBesides the planets, millions of small worlds go around the Sun. Asteroids are lumps of rock and metal, most of them between Mars and Jupiter. Dwarf planets like Pluto are round but share their path with many other worlds. Comets are lumps of ice and dust that grow a tail pointing away from the Sun when they come near it. A shooting star (meteor) is a tiny grain from space burning up in the Earth's air.Opens after: Giant planets
  8. The size of the solar systemLockedThe solar system is almost all empty space. If the Sun were a football, the Earth would be a peppercorn 21 metres away, Jupiter a grape 112 metres away and Neptune a pea about 650 metres away - and the nearest other star would be another football thousands of kilometres away. Even light takes about 8 minutes to reach us from the Sun.Opens after: Small worlds, The Earth

Connections to other domains