The Big Bang Theory Of How Universe Came To Be (Where Did We Come From?)

Man has demonstrated profound enthusiasm towards understanding the nature of universe and how we all came to be from unrecorded time during which criteria to establish this universal truth were mainly influenced by philosophy and religion. In those ancient times, there was no scientific instrument to confirm the veracity of the opinions of renown philosophers and religious irredentists on the true nature of the cosmos. Hence, the prevailing notion that earth was at the centre of universe and that everything else existed to support human life and destiny, was generally accepted by the ancient population. In our ignorance, even as late as 1920s we didn't know that our galaxy was just one among many in an ever expanding universe.

_{[A representation of big bang expansion model. Source: wikimedia commons. Author: NASA/WMAP Science Team. Public domain image]}

The notion of the earth being the centre of the universe continued to hold sway among the ancient people until around 2300 years ago when some critical observers in the Mediterranean came up with the concept that earth must be round and orbiting the sun. This was supported by the Italian astronomer Galileo Galilei following his invention of astronomical telescope some 1,900 years later with which it was now possible to make precise observations about the planets and stars; giving rise to the science of structure and history of the universe known today as cosmology.

Ever since then, many theories have been propounded by various astronomers, scientists and cosmologists to explain the origin of universe; popular among these are the steady state universe theory, the eternal inflation theory, the oscillating model theory^ref and the Big Bang theory of origin of the universe, which happens to be the one that will form the basis of this article.

The Big Bang theory

Big Bang theory is an attempt to explain what really happened at the very beginning of the universe, and it seems to be the only theory that is widely endorsed by virtually all cosmologists and scientists to this day. Many discoveries in astronomy and physics are valid proofs, without any doubt, that indeed the universe did has a beginning. Before that moment, there was nothing but during and after that moment, there was something, which happens to be the universe as we know it today. To explain what happened during and after that moment, is the chief goal of the Big bang theory.

_{[In this illustration, XDF is separated into three planes which shows foreground, background, and very far background galaxies. These divisions are reflections of different events in the evolving universe. Fully mature galaxies are represented within the foreground plane indicating galaxies as they looked fewer than 5 billion years ago. Evolving nearly mature galaxies occupied the universe from 5 to 9 billion years ago. Beyond 9 billion years the universe is filled with compact galaxies and proto-galaxies that are characterized by young stars^ref. Source: wikimedia commons. Author: NASA, ESA, and Z. Levay, F. Summers. Public domain image]}

This prevailing cosmological model for the universe posits that universe started as an extremely hot, dense point generally referred to as singularity some 13.8 billion years ago, and tries to describe the series of events that result into what we have today. It holds that following the appearance of this zone of infinite density and extreme temperature (i.e the singularity), is the period of rapid inflation during which the tiny, extremely hot zone expanded exponentially and doubled in size at least 90 times for a moment. It then slowed down after this initial expansion to continue to grow at a slower rate. As it grows, temperature is cooled making space particles to clump together and form stars, galaxies and matter as we have them today. These ever-increasing expansion and cooling of the universe continue to this day.

So there was never an explosion of the gravitational singularity as the sound of the Big Bang model might represent. Rather, it underwent a period of inflation, which was characterized by rapid expansion of what later come to be known as the universe. Click here for further details about the Big Bang theory.

Evidence of the Big Bang Theory

From what we have said so far, it is obvious that most scientists and cosmologists are in agreement regarding the Big Bang theory of the origin of universe which is said to have originated some 13.8 billion years ago. But how do we authentic this? Any clue about this occurrence that supposedly happened a long time ago? Of course, there are many clues — the remnants of the Big Bang that authenticate this theory. Let's dig up some of them here.

The fact of ever expanding universe

In 1929, Edwin Hubble stated, after analysing galactic redshifts, that galaxies are drifting farther and farther away from us at speeds proportional to their distance, and thus constituting an important observational evidence consistent with the theoretical model of an expanding universe earlier hypothesized in 1927 by George Lemaitre. It was then deduced that if the galaxies are moving away from us, it then means that the universe is ever expanding. If this is so, it means that there was a time in the past that universe is much more compact and various galaxies were closer to one another. Move back into the past far enough, and you will realize there was a moment these galaxies and all matter in the universe were packed into a single point from where they all began to move outwards. That moment represents the Big Bang.

_{[Panoramic view of the entire near-infrared sky shows how galaxies are distributed beyond the Milky Way.
^ref. Source: Wikimedia commons. Author: IPAC/Caltech, by Thomas Jarrett. Public domain image]}

Detection of the remnants of cosmic heat

Scientists predicted that if the universe was indeed initially very very hot as the Big Bang theory would want us believe, then there must be remnants of this heat today. This view was expressed 20 long years before the discovery of the cosmic microwave background radiation in 1964 by the duo of Radioastronomers Arno Penzias and Robert Wilson for which they shared in the 1978 Nobel Prize for Physics for their discovery.

The above stated facts that confirm the Big Bang model are just a tip of the iceberg, there are many other equally convincing facts which cannot be adequately addressed in a blog article but which I will leave a link for interesting parties to read up. You can click here to read more interesting facts. That said, this article represents what's thought to be the popular opinion among scientists with respect to the origin of the universe, and so it does not conform to theological/religious views as to how the universe as we have it today came to be; it took far more than 7 days to create the universe, cosmologically and scientifically. Thanks for reading.

References

• _{The history and structure of the universe (info graphics)}
• _{The origin, history, evolution and future of the universe}
• _{The universe: Big Bang to now in 10 easy steps}
• _{Big Bang theory}
• _{Big Bang}
• _{What are the events that happened during the Big Bang?}
• _{How do we know the Big Bang actually happened?}

Truly yours,
@sciencetech
STEM Contributor.