The big bang

The Big Bang theory is the prevailing cosmological model for the universe.  The Big Bang theory is an effort to explain what happened at the very beginning of our universe. At its simplest, it says the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today. The model describes how the universe expanded from a very high-density and high-temperature state, and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure and Hubble's law. There are many misconceptions surrounding the Big Bang theory. For example, we tend to imagine a giant explosion. Another misconception is that we tend to image the singularity as a little fireball appearing somewhere in space.  The cosmic microwave background has been observed on many missions. One of the most famous space-faring missions was NASA's Cosmic Background Explorer  satellite, which mapped the sky in the 1990s. The known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature. The universe is expanding. Every planet and other things are getting far from each other. It is the proof of universe is formed by big bang.