Where did the universe come from?

Numerous mythology and scientific hypotheses have attempted to explain the beginnings of the universe throughout history. The most widely accepted theory is the Big Bang theory—a colossal explosion that ushered the universe into existence. Join me to discover how the universe expanded from the size of an atom to include everything that exists today and the explosion that caused it all.

The Big Bang was developed in response to the discovery that galaxies outside of our own are travelling very quickly in every direction, as if they had all been propelled by a powerful explosive force in the distant past. It was first put forth in the 1920s by a Belgian priest by the name of Georges Lemaitre. He suggested that the universe originated from a single primordial atom. Edwin Hubble’s discoveries that galaxies are accelerating away from us in all directions, as well as Arno Penzias and Robert Wilson’s discovery of cosmic microwave radiation in the 1960s, which they interpreted as echoes of the Big Bang, gave the theory significant boosts.

How the universe began

It occurred in stages or epochs.

1. Singularity epoch

This was the earliest known time of the universe and is also referred to as the Planck Epoch (or Planck Era). All matter was concentrated onto a single point at this time, which was extremely hot and had infinite density. It is thought that during this time, gravitation’s quantum effects largely dominated physical interactions and that no other physical force could compete with gravity in power.

Since it can only be measured in Planck time, this span of time, which starts at point 0 and lasts for around 10-43 seconds, is known as the Planck period. The universe was in a very unstable state because of the intense heat and density of matter. Thus, it started to grow and cool, which triggered the appearance of the fundamental forces of physics.

The universe started to cross transition temperatures between 10-36 and 10-43 seconds. It is thought that here is the location where the fundamental forces that control the universe started to separate from one another. The separation of the gravitational force from gauge forces, which are responsible for the strong and weak nuclear forces as well as electromagnetism, was the initial stage in this process.

The universe’s temperature dropped to a level (1028 K) where the electromagnetism (strong force) and weak nuclear forces (weak interaction) could also divide, giving rise to two different forces between 10-36 and 10-32 seconds after the Big Bang.

The universe started to cross transition temperatures between 10-36 and 10-43 seconds. It is thought that here is the location where the fundamental forces that control the universe started to separate from one another. The separation of the gravitational force from gauge forces, which are responsible for the strong and weak nuclear forces as well as electromagnetism, was the initial stage in this process.

The universe’s temperature dropped to a level (1028 K) where the electromagnetism (strong force) and weak nuclear forces (weak interaction) could also divide, giving rise to two different forces between 10-36 and 10-32 seconds after the Big Bang.

2. Radiation epoch

This period only covered the first tens of thousands of years following the big bang, was given its name because there was an excess of radiation during this period.

The era can be thought of as being made up of many shorter epoch stages, the majority of which lasted under a second. Since the world was not governed by the physics that we now understand during those earlier epochs, much speculation still surrounds them.

The epochs include.

     Planck Epoch

There was just one superforce present which would subsequently develop into the dominant forces we observe today. Gravity emerged toward the conclusion of the Planck period. Planck time, the smallest quantifiable unit of time, is how the epoch got its name.

     Grand Unification Epoch

Strong nuclear force separated from the superforce 10-43 seconds after the great bang,

     Inflationary Epoch

The universe rapidly expanded which occurred 10-36 seconds after The Big Bang. The only particles in the cosmos were quarks and electrons, which were still extremely hot.

     Electroweak Epoch

Electromagnetic force and weak nuclear force separated from the superforce during this epoch, which occurred 10-32 seconds after the big bang.

     Quark Epoch

The universe was filled with the necessary particles to create a complex system at, 10–12 seconds after The Big Bang, but the temperature and density were still too high to support it.

     Hadron Epoch

The creation of protons and neutrons from quarks began. It occurred 10–16 seconds after The Big Bang, when the temperature dropped to 1010 K.

     Lepton Epoch

The temperature was 1012 K approximately one second after the big bang.

     Nuclear Epoch

At 109 K, 100 seconds after the great bang, the temperature and other conditions were suitable for the fusion of protons and neutrons into nuclei. Thus, helium atoms were produced.

3. Matter epoch

The era of matter, in which matter rules the cosmos, began when the universe was able to and under the right conditions to create elements. This time period includes the millions of years following the radiation era, during which the cosmos expanded, altered, and took on the appearance we recognise today.

     Atomic/Inflation Epoch

50,000 years after The Big Bang. The cosmos reached 3,000 K, it had cooled enough for electrons and nuclei to combine to form atoms. Hydrogen atoms were produced because of the recombination process.

     Galactic/Cooling Epoch

Atomic clusters were created 200 million years after The Big Bang, a significant amount of time before they evolved into galaxies.

     Stellar/Structure Epoch

Star formation in the galaxies started 3 billion years after The Big Bang. The cosmos evolved into the state that it is in at this time. After the formation of planets and all the other elements, life began to develop. This time period, also known as the Stelliferous Era, spans from the present to a future time when stars will no longer develop.

The future for the universe

There are numerous unanswered questions regarding The Big Bang theory. Dark energy and dark matter are two examples of phenomena that scientists still find difficult to explain. There are some contradictions that require resolution.

What lies ahead for the cosmos is continuously expanding and cooling is one of the important issues. Will all matter eventually condense into a small speck when the cosmos runs out of force that makes it expand? Or will the cosmos continue to grow forever? The “Big Crunch” refers to the first scenario.

The “Big Freeze” refers to the latter scenario of unlimited expansion, which is thought to be more likely. Here, the cosmos continues to expand and cool eternally until it reaches a temperature where nothing can survive, including life.

A Degenerate Era will follow the end of the Stelliferous period and, with it, the cessation of star formation. This will cause the cosmos to enter a Dark Era, which will be followed by a Black Hole Era.

These are, of course, just conjectures, but with scientific progress and new technological developments, we can only hope that it will not be long until we know more or all of the answers.