The Big Bang is a massive event that occurred 13 billion years ago, leading to the formation of the universe. Read more for additional facts...

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The Big Bang

Hello Readers!

The Big Bang Theory revolves around a catastrophic explosion13 billion years ago that led to the birth of the universe and its evolution till date.

The evolution of the universe is divided into many stages. Let's cover them.

Stage 1: Initially, the universe was made up of nothing. Neither space or time existed. Suddenly, the universe appeared from nothing. It grew and finally exploded, emitting all types of radiation. This phenomenon was termed as the Big Bang.

Stage 2: The universe was born as energy. Just after its birth the recorded temperature was 10^28 Kelvin. As it cooled down, the free energy formed subatomic particles and antiparticles. Most of these annihilated one another and turned back to energy, but some were left out. They began to form stable atoms.

The universe was less than a millionth of a second old when hydrogen and helium atoms formed. 

 

^{Stage 3: 390,000 years later the temperature had dropped to 3000 K. Since the volume of the universe was so massive, light can go unhindered in any direction without colliding with any atoms. This light is called Cosmic Microwave Backround Radiation (CMBR) which is a definitive proof for the Big Bang Theory.}

Cosmic Background Radiation has travelled round the whole universe and came to earth after 13.8 billion years. Meanwhile, the universe had expanded about 1000 times. The 3000 K light was stretched into 3 K waves.

Stage 4: Post 400 million years, the clumps of dust and gas began to form rotating discs. Due to nuclear fusion, the centres shone as the first stars. They were held by gravity within big clumps called galaxies. The first galaxies had no shape but soon merged and developed spiral shapes.

The age of our own galaxy The Milky Way is 13.56 billion years, which suggests it was formed when the universe was 560 million years. Post 8 billion years, the expansion of the universe began to accelerate due to an unknown force.

Stage 5: After 9 billion years, the solar system formed through a nebula containing gas and dust.

There are many proofs to this theory apart from the CMBR. One of the principal evidences is the reddish colour of distant galaxies.

The Color Spectrum

In 1929, Edwin Hubble observed that light coming from distant galaxies was redder than it used to be. This phenomenon is called Redshift, where light shifts to the right end of the spectrum as the object moves away.

Thank you for reading!

Aditya VN Kadiyala