Earth, the planet we live on, is about 4.5 billion years old. At least, scientists think that’s how old it is because of some really, really ancient rocks in Australia that come from about that long ago.
Since there was no-one around 4.5 billion years ago, we don’t know for sure how the Earth and the other planets in our solar system were made. But scientists who study stars and planets millions of miles away in Space have been able to do experiments to learn about how other galaxies (enormous collections of stars and planets) are formed. And they think this must be how our planet was made, too.
So let’s find out more about how the Earth got started…!
Before our planet was made, the Sun (the bright star that is now at the centre of our solar system) was surrounded in Space by dark clouds of hot gases and bits of dust. These gases and dust bits swirled around, bumping together until the dust bits started to clump together and make rocks. The rocks and dust bits clumped together some more to make bigger and bigger rocks until they made the huge hot rock blob that became Earth.
The baby Earth cooled down and became the third planet from the Sun. It has a hard crust of solid rock, which is the outer layer that we live on. Underneath the crust is the ‘mantle’, which is made up of hot, melted rocks (known as ‘magma’). In the middle, is the Earth’s ‘core’, which is made up of super hot metal. You can find out more about the structure of the Earth here.