Dear Students, It is difficult to say how earth originated. As a matter of fact, nobody has been able to give the exact cause and time of the origin of the earth so far. It is still a debatable question. Different scholars have expressed different views on the subject, but m ost astronomers believe the Universe began in a Big Bang about 13.7 billion years ago. At that time, the entire Universe was inside a bubble that was thousands of times smaller than a pinhead. It was hotter and denser than anything we can imagine. Then it suddenly exploded. The Universe that we know was born. Time, space and matter all began with the Big Bang. In a fraction of a second, the Universe grew from smaller than a single atom to bigger than a galaxy. And it kept on growing at a fantastic rate. It is still expanding today. As the Universe expanded and cooled, energy changed into particles of matter and antimatter. These two opposite types of particles largely destroyed each other. But some matter ...