In almost every culture, our ancestors told creation stories. These creation stories differ from one another as much as the communal religion. Some are but copied works of others embellished. Limited to their eyes only, understandably these stories are been filled with myths than facts. Facts are closer to the truth than myths. For that, science now took over.
In this regard, our scientific generation tells its own creation story. A story filled with facts than any myths. Therefore, with all our ground and space telescopes as well as particle accelerators simulating the earliest conditions possible, we should revisit the site of creation. It is a long journey. So long, demanding and tortuous that earned intelligence begins to look like unearned stupidity as we approach the site and the moment of creation.
That is why it will be instructive to remind you of a quote from G.K. Chesterton that "the poet only asks to get his head into the heavens. The logician seeks to get the heavens into his head. And enter, it splits". Well your head as a logician will split in the journey from the observable into the unobservable as well as from the knowable into the unknowable if you stick to common sense or the old logic.
You must spot the limitations as we descend into the unobservable microscopic world of fuzziness where it all got off. The poet, of course, is not so much concerned with describing facts as creating images in his own image to establish mental connections to get his head into the heavens. Mythology does that easily. The logician, the refined logician must do so via facts, at least via the currently deducible mathematical models. So come along as we walk through our creation story, the story of the Big Bang.
In science, a theory is a knowledge that explains a body of observations. That is not all. More importantly in science, knowledge is predictive; therefore, a theory must have the capacity to predict what is observable for scientists to probe further. In this regard, the Big Bang theory explains certain observations at least about the Observable Universe and, made some predictions. Yet a theory can be correct but incomplete.
Another indispensable component underlying science is modeling. A model is a mathematical construct based on the working theories for evaluating the predictions of such theories. Remember science journeys from the observable to the unobservable, therefore the known to the unknown. Whilst the theories help in the world of the knowable and observable, the models equally illuminate the world of unknowable and unobservable. So with this general background, let us take off with the familiar to contrast with the Big Bang theory.
We are familiar with explosions. It involves Matter producing energy in a rapid interaction called reaction. Some portions of the Earth quakes or explodes sometimes, releasing energy to destroy anything in its wake. Then men built explosives. In a generation of industrialism, militarism and terrorism explosions happen accidentally as well as intentionally.
In all these, released energy ends up transforming Matter to the less useable form. This means Matter moving from an organized to chaotic form. This is what we know or are familiar with as explosions. Was the Big Bang that same kind of explosion? Come along as we sail via the evidence for the theory.
THE HUBBLE EXPANSION
Our eyes are limited for long distance observations. Telescopes become their extensions. They are portals of discovery, revealing how the heavens go. So when Edwin Hubble turns his telescopes onto the heavens, wherever he looks he observed that the galaxies were moving away from one another. Scientists called the phenomenon the red-shift Effect. This red-shift phenomenon of light is similar to the familiar sound effect called Doppler Effect.
When we stand at the roadside, we can tell via the sound or horn of a vehicle whether it is moving away or towards us. The sound fades continually as the vehicles move away from us. This is the Doppler Effect. Hence, the red-shift phenomenon tells a story. The galaxies are receding way from one another. If they are receding away from one another at that speed, then it makes sense to assume that, probably sometime in the distant past they were closer. We can even go further that they were extremely close.
THE COSMIC BACKGROUND MICROWAVE
Meanwhile, when Arno Penzias and Robert W. Wilson also turn their telescopes into the heavens, they were picking some unwanted radiations. They were not looking for this radiation and they did almost everything as improvement in the telescope to weed it out assuming it was an earthly and systemic fault. No, it was not. It kept pouring in from all directions no matter what they do.
Since this radiation is coming in from all directions with almost the same temperature, it makes sense to see it as a kind of background effect. This particular cosmic relic radiation is noticeable even today in our homes in our TV and radio channels via the ordinary antennas, not the satellite dishes. The antenna that brings radio and TV signals for the channels are continually been interrupted by these photons called microwave background. On radio, it sounds "shuuuushuuu" and on TV, it appears as collocations of fidgeting "balls" in the absence of any particular channel with the "shuuuushuuu" background on any frequency.
This radiation also tells a story. Yet, to what was it a background effect? To find out, we need to turn to the explanatory power of the leading diametrical theories: Relativity theory of the largest and the Quantum mechanical theory of the smallest.
Stay tuned, it is a long journey.........