According to this theory, about 15 billion years ago (15,000,000,000) the Universe was nothing more than a very small speck of mass. This speck was probably no bigger than the head of a pin. Everything in the Universe, all the galaxies, stars, planets, and even the matter making up your body was squished up tightly in this tiny space.

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Eventually, after a very long time, this speck exploded. All of a sudden, in a giant flash of unimaginable heat and power, the Universe was born. Over a period of billions and billions of years, the Universe became what we see today. Slowly stars began to form, and around these stars, planets formed.

In a quite galaxy known as the Milky Way, about two thirds of the way towards the outside of the galaxy, there formed a medium sized yellow star, which would come to be known as Sol. Around that star, formed nine planets. (There is controversy as to whether Pluto is really a planet). One of those planets, the third in distance from that star, was a small rocky planet called Earth.