Universe, as we all know is everything that exists, from the tiniest subatomic particles to clusters of stars. The Earth is only a tiny speck in the universe. Scientists are still unable to determine how big the universe is. But it is estimated to contain atleast 100 billion galaxies, each of which contains on an average, 100 billion stars.
Everything in the universe has an origin – a beginning. Likewise, the universe itself must have an origin. There must be a point in time when it all came into existence. Perhaps, the ‘Origin of the Universe’ still remains one of the most intriguing mysteries that scientists have ever faced. Many theories have been proposed to explain how the universe came into existence. The most dominant and widely accepted theory is the ‘Big Bang Theory’. According to the Big Bang theory, the universe came into being from a huge explosion that took place 10 to 20 billion years ago. Universe, as we know today is the result of this incredible cosmic explosion. The theory suggests that, the whole universe came from a small speck of infinite density known as the ‘Singularity’, which then exploded and hurled matter and energy in all directions. The universe initially consisted of a hot, dense fireball of expanding gases. Over a period of time, the hot gases began to cool and condense to form the Protogalaxies. These protogalaxies continued to condense during the next five billion years to form the galaxies in which stars were being born. But ever since the explosion, the universe has been continuously expanding, which is evident from the Doppler Shift of the stars. Observations have revealed that the light from the distant galaxies tend to shift towards the red end of the spectrum which means that the galaxies are moving farther away from each other.
Nobody knows why or from where this ‘Singularity’ appeared and what existed prior to this event. Scientists are still trying to solve this puzzle. Eventually, you cannot give any scientific explanation as to what exactly happened, because the laws of science become meaningless at ‘Time Zero’ i.e. the point when the explosion is believed to have taken place. If only we can travel trough time, we would be able to find out what really happened.
