9781422283691

Format ion and St ructure   The Earth is made up  of layers, rather  like a gigantic onion.

The Earth was born at the same time as the other planets in the Solar System , about 4,600 million years ago. It formed out of lumps of rock whirling in space around the early Sun. The lumps collided and stuck together to form the very large round mass we now call the Earth. The newborn Earth was very hot and molten (liquid) and took millions of years to cool down. As it cooled, gravity pulled heavy metals, such as iron and nickel, to the center, while lighter materials settled above it. This created a layered Earth. Geologists work out the structure of the Earth by tracing how earthquake waves travel through underground rocks.

∆ How the Earth formed.

1 Small lumps of matter stuck together to form large ones. 2 In time, a body the size of the Earth formed and became hot. 3 Later, gases coming out of the ground formed the early atmosphere. 4 After billions of years, Earth turned into the body we know today.

Inside the Earth there are different

layers. The crust and mantle are made up of rock, but the core is metal.

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