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The Solar System

Our solar system is the Sun and everything bound to it by gravity: eight planets, at least five dwarf planets, and hundreds of moons, along with countless asteroids and comets. The four inner planets — Mercury, Venus, Earth and Mars — are small and rocky. The four outer ones — Jupiter, Saturn, Uranus and Neptune — are giants, the first two made mostly of gas and the last two of ice.

Beyond Neptune lies the Kuiper Belt, home to Pluto and other dwarf planets. Some of the most fascinating worlds are moons: Titan has lakes of liquid methane, Europa hides an ocean under ice, and Io is the most volcanic place we know. Here is a tour of the most important objects, each with a fact to remember it by.

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ObjectTypeFact
☀️ SunStarThe star at the center of the solar system.
🪐 MercuryPlanetThe smallest planet and the closest to the Sun.
🪐 VenusPlanetThe hottest planet, wrapped in thick clouds of acid; close to Earth in size.
🪐 EarthPlanetThe only planet known to support life; about 71% ocean.
🪐 MarsPlanetThe Red Planet, home to Olympus Mons, the tallest volcano in the solar system.
🪐 JupiterPlanetThe largest planet, marked by a centuries-old storm called the Great Red Spot.
🪐 SaturnPlanetThe gas giant famous for its bright, wide ring system.
🪐 UranusPlanetAn ice giant that spins on its side, tilted almost 90 degrees.
🪐 NeptunePlanetThe farthest planet from the Sun, a windy deep-blue ice giant.
🌑 PlutoDwarf planetA famous dwarf planet in the Kuiper Belt, reclassified in 2006.
🌑 CeresDwarf planetThe largest object in the asteroid belt, and the closest dwarf planet.
🌑 ErisDwarf planetA distant, massive dwarf planet whose discovery led to Pluto's reclassification.
🌑 MakemakeDwarf planetA bright, reddish dwarf planet far out in the Kuiper Belt.
🌑 HaumeaDwarf planetAn egg-shaped dwarf planet that spins so fast it is stretched out.
🌙 MoonMoonEarth's only natural satellite.
🌙 TitanMoonSaturn's largest moon, with a thick atmosphere and lakes of liquid methane.
🌙 EuropaMoonA moon of Jupiter thought to hide an ocean beneath its icy crust.
🌙 GanymedeMoonThe largest moon in the solar system, orbiting Jupiter.
🌙 CallistoMoonA heavily cratered Galilean moon of Jupiter.
🌙 IoMoonThe most volcanically active body in the solar system, a moon of Jupiter.
🌙 EnceladusMoonA small moon of Saturn that erupts icy geysers into space.
🌙 TritonMoonNeptune's largest moon, which orbits in the opposite direction to the planet.
🌙 PhobosMoonThe larger of Mars's two tiny moons.
🌙 DeimosMoonThe smaller, outer moon of Mars.
🌙 CharonMoonPluto's largest moon, roughly half its size.
☄️ Halley's CometCometA famous comet that returns to Earth's skies about every 76 years.
🪨 VestaAsteroidOne of the largest bodies in the asteroid belt.

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