Question

How actually or really the universe is formed

OR

How the big bang formed or why the big bang formed ?

Answer 1

Around 13.8 billion years ago, all the matter in the Universe emerged from a single, minute point, or singularity, in a violent burst. This expanded at an astonishingly high rate and temperature, doubling in size every 10-34 seconds, creating space as it rapidly inflated. Within a tiny fraction of a second gravity and all the other forces were formed. Energy changed into particles of matter and antimatter, which largely destroyed each other. But luckily for us some matter survived. Protons and neutrons started to form within the first second; within minutes these protons and neutrons could fuse and form hydrogen and helium nuclei. After 300,000 years, nuclei could finally capture electrons to form atoms, filling the Universe with clouds of hydrogen and helium gas. After around 380,000 years it left behind a bath of photons – the Cosmic Microwave Background that Penzias and Wilson accidentally detected. Within this were tiny ripples of matter that were stretched to enormous sizes during inflation, and in turn these became the seeds for the galaxies and galactic clusters we see today.