The Big Bang and the Steady State

 

The Big Bang

Many scientists believe that the Universe formed because of a gigantic explosion called Big Bang. it took place about 13.7 billion years ago when all the matter and energy of the space was squeezed together into a single point of unimaginable temperature, pressure and density. Then it exploded and expanded outwards into a massive spinning cloud of dust and gases forming a nebula. The nebula developed localized clumps of gases that continued to grow producing enormous heat, eventually forming the stars. One such star that came to existence was our Sun.

Initially, the sun spun like a giant disk with particles orbiting it. Eventually, these particles coalesced to form the planets of our Solar System including Earth. 

Earth came into existence about 4.5 billion years ago. In the beginning, it underwent phases of melting, volcanism and crashes by asteroids.

The Steady State

An alternative to the Big Bang, the Steady State theory said that there was no beginning or end for the universe and that it has just always been there. Few scientists now believe in the Steady State Theory.

Picture credit: Wikipedia