How the Universe Began 

You've probably heard about the big bang theory, but do you actually know the events that happened?

Last updated 13 May 2026

The big bang theory is the single-most accepted scientific theory that explains how the universe began. According to this theory, the universe started as a very dense, hot and small single point 13.8 billion years ago.  Discovered by American astronomer Edwin Hubble, this theory was initially met with a lot of skepticism, with some scientists even dismissing it. Edwin had discovered that galaxies are moving away from each other. This discovery of galaxies moving away was then proven and it was found that the speed at which the galaxies are moving away is accelerating. 

The dense hot single point then exploded and small particles started forming. After that, bigger articles like protons and neutrons formed. While all of this was happening, which was within minutes, the universe was cooling.  The protons and neutrons then   came together to form the nuclei, which is the core of an atom. But an atom was not formed yet, just the nuclei. After another few minutes, the universe cooled even more, and protons and neutrons could no longer come together. All that was left were electrons and nuclei.

This lasted for hundreds of thousands of years. About 380 000 years later, electrons and nuclei came together to form atoms. Another hundreds of millions of years passed. Eventually, stars started to form and later, the universe as we know it.

In 1964, two radio astronomers Arno Penzias and Robert Wilson discovered a radiation that fills all of space. This radiation was later called the cosmic microwave background and was accepted by scientists as evidence of the Big Bang. It is a light that travels throughout the universe and is said to have come from the Big Bang or the explosion that led to the forming of the universe. It is, put simply, an echo from the big bang. Penzias and Wilson went on to be awarded the Nobel Prize for Phyiscs in 1978 for their discovery.

Sources and Further reading:

• Britannica: Big-Bang model | https://www.britannica.com/science/big-bang-model

• Institute of Physics: How did the universe start? | https://www.iop.org/explore-physics/big-ideas-physics/big-bang

• NASA Space Place: What is the Big Bang? | https://spaceplace.nasa.gov/big-bang/en/