The Birth of a Planet

by Emily Noy

The Big Bang

Almost 14 billion years ago The Big Bang occurred. This event caused a huge amount of energy to be let loose into a small universe.

Stars being formed

Scientists believe that almost immediately after The Big Bang stars formed. Stars form in temperatures less than 240 degrees Celsius below zero. They form in the dark inside of cold clouds of gas and dust.

Supernova explosion

When the stars ran out of fuel they exploded into supernovas, which released thousands of tons of carbon, oxygen and iron into space.

Planet being formed

The atoms of the stars, dust and gas are attracted to each other by gravity and electrical force. These particles grow bigger and bigger and eventually create a planet. Planets grow when dust or objects collide with them.

Iron is the heaviest atom and it makes the centre of the planets. The lighter atoms, like hydrogen, carbon, oxygen and helium go to the surface. The planets were usually shaped like spheres because gravity pulled evenly in all directions.

Earth and sun

The first  planets formed around 14 billion years ago but some planets didn't. But the planets that go around our sun, including Earth, may have formed around 4.5 billion years ago. There are planets still forming today around other stars.

Solar System

Our Solar System has nine planets that revolve around the Sun. Mercury, Venus, Earth and Mars are made mostly of iron and are smaller and harder than other planets. They are close to the Sun so they are hotter. Jupiter, Saturn, Uranus and Neptune were formed farther away from the Sun so they are colder, larger and softer. They are made mostly of oxygen and are called 'gas giants'.

This is a video about the creation of stars and planets.


This is a picture of our planet Earth. We know a lot about it but we still have a lot to learn about the rest of the Universe.

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