There are many hypothesis about the origin of the universe. But the best of them all is considered to be big-bang-theory. Which is also known as the Expanding Universe Hypothesis.
According to this theory, the universe is expanding even today. The proof of this was given by Edwin Hubble in 1920. Galaxies continues to expand and move away from each other.
What is the Big Bang Theory ?
According to the Big Bang Theory, as we see our universe today. It was not like this in the beginning. Initially there was a tiny ball which had Infinity Temperature, Infinity Density and Small Volume. All this matter was gathered in one place.
One day this ball exploded with great speed and everything exploded and all the matter spread in the whole universe. This incident happened 13 point 7 billion years ago. This expansion continues to this day. Some of this energy got converted into matter. Shortly after the Big Bang, the first atom started taking form.
The expansion of the Universe is happening in such a way that the space between the galaxies is increasing. Today the Universe has become so much bigger than a singularity.
In which there are countless galaxies and no stars are counted. The universe is infinite. It has no limit. The universe itself is a wonderful thing to us. But what is even more surprising is how a hot and dense point turned into infinity.
Four things were created because of the Big Bang Theory. number 1 Matter! number two Space! No. 3. Time! Number 4 Energy!. Along with the Big Bang Theory, many forces came into existence such as Gravity, Strong Nuclear, Electromagnetic etc.
The galaxies in this universe are stars that we can see or scientists have known so far, that is only 5 percent of the universe. The rest 95% is dark matter and dark energy. Of this 95%, dark energy is 68%, while dark matter is 27% and normal matter is 5%.