The Big Bang Theory (the real scientific theory, not the TV show) is pretty well ingrained in the public consciousness. Most people have a general idea what “the Big Bang” means. In a nutshell, the theory is that everything began with a huge explosion somewhere around 14 billion years ago. Everything that’s out there came from that. Beyond that, most people don’t know what happened. A mistaken conception exists that the stars, galaxies and planets, including Earth, popped into existence fully formed. The real story is a little more complicated and a little more detailed.
Before examining the Big Bang Theory, we need to understand just what a theory is. A theory is a guess as to how to explain what is observed. For example, thousands of years ago, observation that the sun came up and appeared to travel across the sky led to a theory that the sun revolved around the earth. The theory was refined over the years and now is that the earth revolves around the sun. The thing about theories, especially cosmological theories such as how the universe began, can’t be proven. They can only be disproven. If the theory fails to account for observations in the real world, the theory has to be discarded.
In college I had a chemistry professor who was fond of saying “atoms are what they are. If the theory doesn’t explain them, we better get a new theory.” What he meant was that, as scientific measurements and techniques get better, if what we are able to see isn’t explained by the theory, the theory of what an atom is will have to be revised or even discarded.
The Big Bang Theory is in that category. The universe is what it is and if the theory doesn’t explain what we can observe, we better get a new theory. Mankind (when I use the term “mankind” or “man”, I intend to include all of the human race, including women) has had many theories over the millennia about how the world and universe came to be. Several have been rejected precisely because what has been observed isn’t explained, or predicted, by the current theory. In fact, the Big Bang Theory is relatively new, having gained ascendancy over the Steady State Theory only in the last 50 years or so.
Before getting into the particulars of the Big Bang Theory we’ll examine some of the discarded theories and look at the development of science. If we don’t know where we came from, it’s difficult to know where we’re going.