Our Solar System
Our Solar System has four terrestrial planets, four gas giant planets and two belts of asteroids. Until last year, we also had a ninth planet called Pluto. The entire thing orbits the Sun!
Earth is the largest of the terrestrial planets in the Solar System. It is the only place in the universe where life is known to exist. About 71% of the planet is covered in water.
Jupiter is two and a half times as big as every other planet combined. It is known as a gas giant, which means a planet made out of gas without a solid surface.
Mars is named after the Roman god of war and is sometimes called the "Red Planet." Olympus Mons, the tallest mountain in the Solar System, is on Mars, so is Valles Marineris, the biggest known canyon.
Scientists know very little about Mercury, the smallest and innermost planet in our Solar System. It is so close to the sun that it revolves around it once every 88 days, its temperatures reaching up to 470 degrees Celsius.
The Moon is the only satellite, or object that orbits something, that Earth has. It is the fifth largest satellite in the Solar System. NASA's Apollo program was the only mission to land on the moon from 1969 to 1972.
Neptune was named after the god of the sea and is the furthest planet in the Solar System. It is 17 times as big as Earth and very much like Uranus, the planet right next to it. Neptune has 12 moons.
Pluto used to be considered a planet, but now scientists think it is one of the largest dwarf objects in a region called the Kuiper Belt. It is made up of rock and ice and is about a fifth the size of the Earth's Moon.
Not only does Saturn have rings made of ice, rocks and dust, it has Titan, the second largest moon in the Solar System and the only moon to have a significant atmosphere.
The sun is the star at the very center of our solar system, and it makes up 99.8% of the whole thing! The sun is called a yellow dwarf star and scientist think it is 4.57 billion years old.
Uranus is named after the Greek god of the sky. It is the coldest planet in the Solar System and made up mostly of water, ice, methane and gas. Wind speeds on Uranus can reach 250 meters per second!
Venus is named after the Roman goddess of love. It is known as the Morning Star or the Evening Star because it is the brightest object in the sky, other than the moon, at these times of the day.