After the bang of Big Bang

Aayushi Tiwari
11 min readAug 25, 2020

olá folks welcome to another post of Scientific Revelation. When I started my blog, the first post was about the Early universe. Frankly, that was a quite average post so, to make a better comprehension I am writing this post. After giving my full attention to human development and hominin evolution, the next few posts will be all about the chronology and evolution of the universe. Let us travel at the time of the big bang to witness what happened after the bang.

If the rate of expansion one second after the Big Bang had been smaller by even one part in a hundred thousand million million, it would have recollapsed before it reached its present size. On the other hand, if it had been greater by a part in a million, the universe would have expanded too rapidly for stars and planets to form.

Stephen Hawking

The fundamental forces of nature

The discussion of fundamental forces of nature is of immense importance when we talk about the early universe. Although I will write a detailed post regarding this topic, it’s necessary to mention here. There are four fundamental forces of nature. Gravity, Electromagnetism, strong nuclear force, and weak nuclear force. Let’s talk about them in detail.

Gravity and electromagnetism

Firstly, Gravitational force is an attractive force and it works upon every particle of the universe depending on its mass and energy. It acts over a large distance and is the weakest fundamental force but has two distinct qualities that make it master of the heavenly bodies. It is a long-range/distance force and always attractive. That means on the smallest level you might not observe it but when mass increases it dominates over everything. The whole structure of the universe and everything in it starts, galaxies, planets, and black holes are the result of gravity.

The other forces are short ranges and they can be repulsive/ attractive. Gravitational force will always add up but in the case of other forces if they are repulsive they will cancel each other’s effect.

Secondly, Electromagnetism force, that interacts with electrons and quarks (that forms protons and neutrons). It depends on the positive and negative charges. Two positive and two negative are repulsive to each other and it is attractive between opposite charges. Because of this force electrons orbit around the positively charged nucleus of an atom. Without it, there would have been no atoms and particles and eventually no structure.

Weak and strong nuclear force

Thirdly, the Weak nuclear force that is responsible for radioactivity. Bosons are the particle that carries weak force. This force has a property that we call spontaneous symmetry breaking. In simple words, it says at low energy particles seem to be a completely different type but in reality, they are different states of the same particle. At high energies, you can observe them.

Lastly, we have the strong nuclear force. It holds the quarks together in proton and neutron and holds the proton and neutron together in the nucleus of the atom. It is carried by Gluons. The discussion of these forces is important because in the early universe they were united and different states of the same force.

The condition of fundamental forces of nature is very different now than in the comparison of the early universe.

Fundamental particles of the universe

Let us discuss what the building blocks of the universe are. When we are discussing the birth of the universe and its early stages it is important to know the particles it is made up of. After the big bang, cosmic soup consisted of this fundamental particle which then combined in different combinations to make our regular elements like electron and atoms.

The history

Since the time of Aristotle ancient Greeks believed that every matter in the universe is made up of 4 elements, earth, air, fire, and water. These elements react in the presence of 2 forces Gravity (sinking capacity) and levity (rising capacity of air and fire). Aristotle believed that matter could be divided into smaller and smaller pieces. Few others said that matter is grainy and everything is made of various kinds of atoms. That was our first discussion regarding the matter and what they are made of.

Since then we have discovered atomic nuclei, electrons, protons, and neutrons in the first half of the 20th century and other fundamental particles shortly after that.

Let me tell you about the most basic particles which comprise electrons and protons. These Particles are according to the standard model of quantum mechanics.

The quantum world

As we all know nuclei are made of protons and neutrons. Protons have a positive charge and neutrons are charge less that’s why nuclei have a positive charge. Electrons carry a negative charge and due to electromagnetism force revolves around nuclei. Protons are made up of quarks. There are six flavors quarks, up, down, strange, charmed, bottom, and top. Each of these comes in 3 colors red, green, and blue. A proton/neutron formed of 3 quarks with each color. Proton has 2 up quarks and one down quark, on the other hand, neutron consists of two down and one up quark. Particles that are made of the remaining flavors decay fast because they have greater mass. Photons carry the electromagnetic force and gluons carry the strong nuclear force.

Electrons are one of the fundamental blocks. Similarly, it has other heavy particles in the same range, the negatively charged muons, and taus. Muon and tau decay very fast due to their unstable nature and they can only be produced in the particle colliders. Higgs bosons are the quantum ripples in the fabric of space-time and every particle has mass due to this ripple. We also have neutrinos which react very weakly with other particles. Our current technology is not sensitive enough to detect them. These particles are produced in the pair with their antiparticles and coming in contact they annihilate each other.

Inflation in the early universe

Alan Guth suggested the inflationary model for the early universe. In this model, the universe expanded increasingly faster than the speed of light within a short period of time (1026 in less than 10–32 seconds). To explain in simple terms after the big bang in the early soup of radiation and particle temperature was very high. It is thought that at those temperatures fundamental forces of nature were united, like different versions of the same force. As the temperature would fall symmetry would have broken. Gravity is separated first following by other forces.

Supersymmetry and energy of the fabric

When electromagnetic, strong and weak nuclear forces were together in symmetry, the temperature dropped but symmetry remains intact. In this condition, the universe was unstable with more energy. This energy had acted like an anti-gravitational force (we can call it cosmological constant/dark energy). This extra energy had made our universe expand with an even faster rate in an inflationary manner. With this huge expansion any irregularities in the universe smoothed out and it became uniform on large scale. Because of the inflation light had enough time to travel to different regions the universe and carry information. It explains the similarity between two far-away regions in the universe.

It raises the question of how inflation happened. Maybe this anti-gravitational force/ black energy is a property of space itself. Maybe the bang of the big bang happened due to inflation itself. The universe had not exploded form singularity but the energy and radiation were always there which got stretched due to inflation. We shall discuss it in the upcoming posts.

Sources: 1. How Cosmic inflation flattened the universe| PBS spacetime.


When due to strong nuclear force quarks were able to form neutrons and protons, they combined to form the nucleus. This is called nucleosynthesis. The nucleus of the helium atom formed.

As the universe expanded more electrons became unable to avoid electromagnetism attraction. When they combined with nuclei to form atom the universe became transparent to radiation. The first time in the history of the universe we could see far away. It took 382000 years to happen. In the first hydrogen was able to fuse and make helium but it took a long time for atomic hydrogen to formed.

In this starting hot plasma phase hydrogen, helium, lithium a lilt amount of beryllium was produced. Some heavier isotopes of hydrogen were also produced at that time. Because they were unstable they annihilate back into lighter elements.

The formation of heavier elements happened at the core of stars. Some parts of this cosmic cloud were denser than others. Here, gravity had used its magic. Denser parts were able to attract nearby matter because of higher mass. These denser areas became what we call galaxies, clusters, and starts.

Cosmic microwave background radiation(CMBR)

When first atoms were made with the combination of electron and nuclei it torched the entire universe. That was the first time our universe has seen the light. That ancient light has spread across the entire universe and it is what we call cosmic microwave background radiation. Why light was emitted at this process?

Note: There is one thing I need to clear here. Our telescopes can only look to 382000 years after the big bang when light first appeared. We have the rock-solid proof of that time but before CMBR we don’t have observational prove because light first appeared at this time.

The Discovery

In 1965 CMBR was accidentally discovered by Penzias and Wilson. They were looking for a different kind of signal when they started receiving microwave static from every corner and direction of the sky. They thought about the sources from which it could come. IT could be the dust pollution or radio wave from the nearby galaxy. They noticed a peculiar point about CMBR. It is at every point on space with the same intensity and pattern. It was so abundant that it needed an abundant source too.

The mechanism of CMBR

Around almost 400,000(or 382,000) years after the big bang, the universe was foggy full of electrons and nuclei. There was no atom at that time. It was an only ionized soup of nuclei with positive charge and electrons with a negative charge. This plasma soup was emitting the light but it was unable to go far away. As the universe expanded the temperature cools down and reached the limit where atoms could be formed. Now electron and protons could not escape the electromagnetism attraction and they bonded together to form atoms. This process goes on until there was no single electron left. The universe became transparent.

The plasma had emitted light just before becoming transparent. This light is what we call now CMBR and studies it as the evidence of the early universe. This first light was orange in color. Due to space expansion, it has redshifted to longer wavelengths eventually becoming microwave.

The free electrons who were bonded by positively charged nuclei given rise to a transparent universe are one of the finest observational prove. Before this, we cannot observe with our current technology. We can only speculate what our universe would have looked like.

Source: 1. Cosmic microwave background radiation explained| PBS Spacetime

Other ideas for the cosmos and matter-energy transition

The timeline of the early universe consists of a few seconds after the big bang to a few thousand years after it. The emergence of CMBR was the end of the early phase.

Now we know that General relativity breaks down at the high temperature of the early universe. If we go back into time like time= 0 we will see that it leads to singularity. Space and time came into existence at the big bang before that there was nothing.

Prove of expansion and other theories

We in reality don’t know much what happened at the time of few fractions after the big bang. People tend to think that the universe began at the big bang. When general relativity was proposed scientists at that time tend to think that the universe is static. Through it, we came to know that it is expending. In 1926 Edwin Hubble proved the fact that the universe is actually expanding. Naturally, if it is expending than it must have started from somewhere. For a long time experts used to think our universe had started from the singularity, time itself formed at the big bang singularity. It is an old concept now because we don’t know for sure.

Maybe hydrogen and helium were always present in the universe for many billion years or maybe our universe formed from the residues of the previous universe? In this scenario, we can’t say that time begun at the big bang. There are many loopholes that we have to discuss for a better understanding of our universe.

Mass-energy conversion

If we talk about the first few fractions of seconds after the big bang it was all plasma and radiation. We have to ask the question of what these particles are made up of. The energy of the universe had materialized itself into fundamental particles. We know that every ounce of energy and matter which is present in the universe came from the bang of the big bang. By the Einstein equation, E= mc2 energy can convert into the matter and vice versa. The immense energy that was produced during the big bang, formed quarks, and other fundamental particles.

There are many mysteries following the bang after the big bang. The advances in technologies are happening day by day. The scientists are working on sensitive observatory which detects the neutrinos. They were also produced following a big bang. A cosmic neutrino background radiation will lead us even closer to the understanding of the universe.


You can read A brief history of time- Stephen Hawking. It is concise and simple to read with a deeper understanding of the cosmos.

Refer to these lectures about the early universe:

  1. Black body radiation and early history of the universe part 1 |MIT OpenCourseWare
  2. Our universe’s first seconds| Dan hooper

Stay tuned and do the revelation.

Learn how to see. Realize that everything connects to everything else.

Leonardo DaVinci



Aayushi Tiwari

Hey everyone. I am a bibliophile and love writing. I am trying to sharpen my hobby of writing regularly. I am always up for new things to learn.