In the beginning our universe was a mass of white-hot vapours and molten materials whirling about in space. Our world was formed from this. Astronomers believe it took millions of years for the cloud to cool, contract and begin to turn into molten rock.
Modern astronomers think that many millions of years ago there was a huge explosion in space. They do not know exactly what happened. But it is possible that our sun exploded or that a much bigger companion star of the sun became a supernova-that is, it broke up violently. The debris and blazing gases from this explosion were, it is thought, flung far into space.
For more millions of years our universe boiled and bubbled. But slowly, very slowly, the fiery redness began to cool and condense into the nine planets and many more smaller bodies. All these planets now revolve around the sun.
After further vast periods of time the lava of the earth began to solidify, developing over many millions of years, into the world as we know it today.