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Origins Origins Introduction Despite being the subject

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					Origins
Introduction
Despite being the subject of thousands of years of study, despite all the powerful technology now at our disposal, the simple question, “Where do we come from?” has yet to be satisfactorily answered. Yet we are closer to solving this riddle than ever before…

Origins of the Universe
The ‘Big Bang’ is the dominant theory about the start of the Universe. It describes how, about 15 billion years ago, a huge cosmic explosion propelled matter in all directions through space. It would be wrong to think of the Big Bang as a normal explosion. It happened simultaneously everywhere, creating space and time in an instant. When the Universe cooled, it also expanded, filling space with sub-atomic particles. These particles gathered in clouds called nebulae and gravity caused the clouds to spin and heat up. When they became hot enough, fusion reactions occurred within the clouds, binding the particles together. The atoms that resulted would become the first stars. Our own Sun formed in this way some 4.6 billion years ago.

Evidence of the Big Bang
While it may never be proven beyond doubt, there is growing evidence to support the Big Bang theory: Hubble discovered that all over the Universe, galaxies are moving away from our own. The Universe can therefore be said to be expanding, possibly as the result of an explosion. In the 1960s, astronomers discovered traces of radiation throughout the Universe, again consistent with a huge nuclear explosion. Scientists have also shown that the Universe today is much cooler – many billions of degrees Celsius - than it was at the point immediately after its creation.

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Rewinding time
In laboratories around the world, scientists are attempting to unravel the mysteries of the Big Bang using huge machines called particle accelerators. They work by smashing matter together at near light speed, conditions similar to those produced by the Big Bang. Scientists hope that as these machines become more powerful, they will get closer to solving the biggest mystery of the Universe.

Origins of our Solar System
Scientists believe that our own galaxy was created 4.6 billion years ago. The nuclear reaction within the nebula that saw our Sun explode into life was also responsible for the creation of the nine planets, including the Earth, that still orbit the Sun today. After this explosion, the temperature immediately began to cool and the gas within the nebula condensed to form solid particles. These particles that surrounded the Sun would continue to react with each other over thousands of years, shaped into balls by gravity which in turn attracted more matter towards them. Some of these balls were formed from heavier, rockier particles. They remained relatively close to the Sun and would evolve into the inner planets of the Solar System – Mercury, Venus, Earth and Mars. Others consisted of lighter, gassier particles and took shape in the cooler conditions at the far reaches of the Solar System. These would become the planets we know today as Jupiter, Saturn, Uranus, Neptune and Pluto. Although this process took hundreds of thousands of years, the planets are still very young. Our Universe is 15 billion years old. If you were to condense this time into one day, the planets would have formed in about 3 seconds, at roughly 5.30 in the afternoon!

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