How Universe Came to Existence?

         

           Even before there have been two sets of opposing ideas, beliefs, theories, or teachings about the origin of the universe. According to the religious belief, universe is created by God. But many scientists contradict this that’s why as time goes by, they study about it and they came up into different theories.

 

            

              Many scientists studied about how universe came to existence. Some had same views and there were also different. The most popular theory in science today is the Big Bang Theory. According to this theory, universe came into existence at a certain point in time roughly 15 to 20 billion years ago. The entire universe was compacted into a teeny tiny little ball, which, after randomly coming into existence for no apparent reason in the first place, exploded into all space, time, matter and energy in an instant. Scientists can't be sure exactly how the universe evolved after the big bang but many believe that as time passed and matter cooled, more diverse kinds of atoms began to form, and they eventually condensed into the stars and galaxies of our present universe. Astronomers have discovered in recent years that the universe is still expanding and this expansion is accelerating.

            The theory called the Big Bounce Theory. This theory states that there was actually something before the Big Bang and it suggests that another universe went through a Big Crunch and then 'bounced' back and then it gave birth to this universe. Scientists believe that about 15 million years ago, the universe was condensed into a small region of matter and energy called a singularity. Suddenly, the singularity exploded, expanding at an incredibly fast rate. Astronomers believe that after the big bang, the universe was like a soup with small pieces of matter floating around. The matter combined to create protogalaxies, which in turn combined to form galaxies. Within those galaxies, gas and dust blended to make stars. And around those stars, gravity pulled pieces of matter together to form planets.

  

               The Cyclic Universe Theory implies that a cyclic universe explodes into existence in a Big Bang, and crunches out of existence over and over again in an endless cycle so space and time exist forever. It states that the big bang is not the beginning of time rather; it is a bridge to a pre-existing contracting era. The Universe undergoes an endless sequence of cycles, which it contracts in a big crunch and re-emerges in an expanding big bang, with trillions of years of evolution in between. The temperature and density of the universe do not become infinite at any point in the cycle; indeed, they never exceed a finite bound.

          

                Another theory is called Steady State Theory. Steady State theory states that the universe had no beginning, but it created new matter as older galaxies moved apart. This implies  that although the universe is expanding, it nevertheless does not change its look over time. For this to work, new matter must be formed to keep the density equal over time.