We think the world is such a big place, but the fact is that Earth is not even the biggest planet in our Solar System, never mind the universe. Let’s just take a look at our Solar System.
Our Solar System is made up of the sun and all of the smaller objects that move around it. Apart from the sun, the largest members of our Solar System are the eight major planets – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
Beyond Mars is the asteroid belt – a region populated by millions of rocky objects. These are leftovers from the formation of the planets, estimated at about 4.5 billion years ago.
On the far side of the asteriod belt are the four gas giants – Jupiter, Saturn, Uranus and Neptune.
These planets are much bigger than Earth, but very lightweight for their size. They are mostly made of hydrogen and helium. Until recently, the furthest known planet was an icy world called Pluto. However, many astronomers think it is too small to be called a true planet.
Another object the size of Pluto, named Eris, was discovered very far from the sun in 2005, and more than 1 000 icy worlds like Eris have been discovered beyond Pluto in recent years. These are called Kuiper Belt Objects.
In 2006, the International Astronomical Union decided that Pluto and Eris must be classed as “dwarf planets