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What is the Solar System?

The planets in order of distance from the SunThe planets in order of distance from the SunThe Solar System consists of the Sun and all the objects that orbit (move around) it. They are: the planets, their moons, asteroids, meteoroids and comets. There are eight major planets. They are, in order of distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto was once described as a planet, but astronomers now call it a dwarf planet. 

The planets' orbits around the SunThe planets' orbits around the Sun

The four terrestrial planetsThe four terrestrial planets

The planets

All the planets orbit the Sun in an anticlockwise direction. They have a rounded shape. They are made of rock, metal, liquid and gas, or a combination of these.

The four inner planets—Mercury, Venus, Earth and Mars—are much smaller than the gas giants and made mostly of rock, with iron cores. They are known as the terrestrial planets.


The Sun is not stationary. Along with billions of other stars, it completes one orbit of the Milky Way Galaxy every 225–250 million years. It travels at about 250 kilometres per second (150 miles per second).

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