Curiosity is welcome here!
Our universe is a beautiful place, it contains everything we know about and everything we aspire to know about. It gave us birth and one day, unfortunately, will bestow upon us death. There are an infinite number of secrets hidden inside the cosmos and this organization is entirely dedicated to uncovering them, we strive to spread the love for science to as many as possible!
Our universe is theorized to have begun approximately 13.8 billion years ago. Thousands of scientists have tried to come up with a logical explanation for the ‘beginning’ of our universe yet there is only 1 widely accepted theory, “The Big Bang Theory“.
Most people summarize the big bang to be an explosion which created the universe and then that’s it. That summarization is in fact very true but to understand the origin of our universe a little substantially you need to delve deeper into scientific facts and explanations which are pretty simple to understand.
The formation of our universe is divided into two Eras:
- The Radiation Era
- The Matter Era
Each of these eras are divided into specific periods of time or ‘Epochs’. Each epoch has a very distinct and essential role in the formation of the universe.
We can Imagine each era to be one school day and all the epochs as the classes that comprise that particular school day. Each class is of a different subject and those separate subjects help you score better on your test.
Now, keeping all these points in mind lets move towards understanding the significance of each epoch.
The Radiation Era
Right after the big bang occurred the very small universe consisted of no mass and was mainly dominated by radiation and energy. This is the reason why it is called the Radiation Era.
It is mainly divided into eight epochs:
1) The Planck Epoch
2) The Grand Unified Epoch
3) The Inflationary Epoch
4) The Electroweak Epoch
5) The Quark Epoch
6) The Hadron Epoch
7) The Lepton Epoch
8) The Nuclear Epoch
It might seem a little scary to read all these weird names simultaneously but I can guarantee you will be able to understand each of them without any problems.
1- ‘The Planck Epoch’ :
During the Planck epoch the universe comprised of pure energy and the four fundamental forces of nature in a combined form called the ‘Superforce’:
2) Strong Force
3) Weak Force
4) Electromagnetic Force
The temperature at this time was about 10^-36 Kelvin and it occurred at about 10^-43 seconds after the big bang. It is known that no laws of physics applied to the events that happened in this epoch and nobody has actually figured out what happened during this period. This epoch ended with the separation of Gravity from the Superforce.
2- ‘Grand Unification Epoch’ :
This epoch occurred at about 10^-43 seconds after the big bang and the temperature of the universe changed to 10^36 Kelvin.
Previously,Gravity had already separated from this unified force at the end of the Planck Epoch, and now at the end of the Grand Unification Epoch, the Strong Force separated too.
3- ‘The Inflationary Epoch’ :
This epoch lasted from 10^-36 seconds to 10^-32 after the big bang.
During this Epoch the universe underwent something called ‘Cosmic Inflation’. The universe expanded at an extremely fast rate. It went from the size of the tip of a needle to the size larger than the radius of the earth Earth.
At this time the universe was still extremely hot and contained various particles like Quarks, Anti-Quarks, and Electrons.
4- ‘The Electroweak Epoch’ :
At this point of time, two major forces were still unified-The Weak Force and the Electromagnetic Force.
During this period of 10^-32 seconds to 10^-12 seconds after the big bang, these last two forces separated and we had all our four fundamental forces separated and independent.
5- ‘The Quark Epoch’ :
This epoch began at 10^-12 seconds after the big bang, with the temperature of the universe now reduced down to about 10^16 Kelvin, but it was still extremely hot.
Even though the universe now practically had all its major components in it, the exceptionally high temperatures wouldn’t allow those components to come together and form any kinds of subatomic particles.
6- ‘The Hadron Epoch’ :
After 10^-6 seconds of the big bang, the universe finally cooled down to 10^10 Kelvin.
This means that universe cooled down enough so that the quarks started to slowly combine and form particles like protons and neutrons which later help in the formation of the first chemical element in the universe-Helium.
7- ‘The Lepton Epoch’ & 8- ‘The Nuclear Epoch’ :
These stages were the ending stages of the Radiation Era, the Lepton epoch started at about 1 second after the big bang and the Nuclear epoch started at about 100 seconds after the big bang.
These two epochs saw a lot change in the universe. The protons and neutrons came together and fused to form nuclei.
Therefore, due to these actions, the cosmos saw its first chemical element called Helium.
The Matter Era
After the Radiation Era ended (elements) matter started to form in the universe. It got filled with galaxies, stars, etc. Hence the name – The Matter Era.
It is divided into three fairly long epochs-
- The Atomic Epoch
- The Galactic Epoch
- The Stellar Epoch
- ‘The Atomic Epoch’ :
During this epoch, the temperature of the universe cooled down to just 3000 Kelvin. This epoch started after about 50,000 years of the big bang.
This cooling down of temperature (possibly due to cosmic inflation) was enough for electrons to bind with nuclei for the first time – forming hydrogen in the process.
This process of the electrons binding with the nuclei for the first time is called ‘Recombination’.
2. ‘The Galactic Epoch’ :
The galactic epoch occurred about 200 million years after the big bang. We now know that helium and hydrogen had been formed already, now during this period of time, these two elements formed Atomic clouds which spread all across the cosmos. Something matter-like finally started to come into existence.
Inside these clouds, small fractions of gas had enough gravity to cause atoms to start collecting.
This process slowly formed various clusters of atoms which would later turn into massive galaxies.
3. ‘The Stellar Epoch’ :
The stellar epoch started about 3 billion years after the big bang. In this epoch, the baby sized galaxies started to develop and form stars and solar systems of its own.
Slowly and steadily planets started to calm down from their hot, volcanic and violent state to comparatively cooler conditions.
This helped life develop and form civilizations of their own. Even though there might be thousands of planets like Earth we haven’t met any other extraterrestrial forms of life, but that discussion is for another post.
Till then see you later.