History #6: The Big Bang

This post marks the beginning of an ongoing series that explores big history. It follows the structure of the college-level course developed by historian David Christian. Bill Gates describes the course this way:

Big history is different from other history courses in that it covers our complete 13.7 billion years of shared history – going all the way back to the Big Bang.  The course then progresses to cover the development of stars, elements, plants, life, humans and our modern-day civilization. These “threshold moments” all share common themes and patterns that are the foundation for the course. To understand the similarities, differences and implications of these thresholds, students have to use many different disciplines spanning cosmology, physics, chemistry, biology, anthropology and social studies.

By connecting different areas of knowledge into one unified story, big history provides a framework for learning about anything and everything. I really like how the course challenges students to wrestle with big questions – questions like how different time scales affect our perspective on history, how language transformed humanity, and what it means to be human. It’s a course I believe everyone should take.

Our big history scale

Douglas Adams, the author of the wonderful Hitchhiker’s Guide novels, once wrote:

The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to be.

We study Big History in order to gain perspective. The universe that we live in is big and old, about 13.7 billion years old. Our brains aren’t designed to conceptualize numbers at that scale so we will be converting everything down to a scale of 13 years.

On this scale: the first stars formed 12 years ago, the earth formed 4.5 years ago, and homo-sapiens emerged about 50 minutes ago. This post will explore what was happening 13 years ago at the start of time. To quote Douglas Adams again:

In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.

Nothing turns into something

Let’s start with what came before the Big Bang. According to the math that best explains our observations of reality, space-time itself wasn’t created until after the Big Bang. Asking what happened before time existed is kind of paradoxical, and is best left to the philosophers. For our purpose, we will use the beginning of time as our starting point.

The Big Bang gave us space, time, matter, and energy. In the tiniest fraction of a second, something many times smaller than an atom inflated into something many times bigger than a galaxy. During these earliest microseconds of existence, the universe was so hot that matter and energy blended together. As the universe cooled, matter and energy separated. Energy began to take the form of gravity and electromagnetism. Matter took the form of electrons and quarks. Those quarks soon linked into protons and neutrons. As the universe cooled to about 1650 degrees, the first hydrogen and helium atoms formed.

Antimatter was also created during the Big Bang and when it combined with matter it was annihilated. Only about 1 billionth of the total matter created during the Big Bang survived. When all was said and done, something unimaginably tiny, dense, and hot had instantaneously exploded into the universe we know today. Over the next 200 million years, or 73 days on our altered time scale, clouds of particles would form and populate the universe.

Claim testing

19th century scientist believed that the universe was static, eternal, and infinite. But, as Olbers’ paradox shows, if this was true the night sky would be filled with an infinite number of stars.

In 1929, Edwin Hubble discovered that light from galaxies produce a Doppler effect. As galaxies move away from us they are more red, and as they move towards us they are more blue. Hubble showed that stars on a whole are flying away from each other. He suggested that everything might be moving away from a single starting point.

If this was true, and everything sprang forth from an initial Big Bang, then there would be a huge amount of radiation associated with that event. In the 1960s, two guy working on an antenna at Bell labs accidentally discovered that radiation. No matter where they pointed their extra-sensitive radio antenna, they would hear the same low static hiss. That hiss was the same frequency that was mathematically predicted by the Big Bang theory. More recently, the discovery of predicted gravitational waves provided a similar kind of evidence of the Big Bang.

Need more proof? How about seeing it with our own eyes. What we see in the night sky is limited by the speed of light. Galaxies that are 13.7 billion light years away can be viewed as they appeared 13.7 billion years ago. What do we see? We see what we would expect to see right after a Big Bang. We see hydrogen and helium and, most importantly, a lot of nothingness beyond.


This story isn’t finished. We are still making new discoveries about the nature of reality at the beginning of time. It was only recently that we discovered dark matter exists, which is a whole other level of weird. But as we opened with, the purpose of this story is perspective.

The Big Bang, which occurred about 13.7 billion years ago, provided the raw material necessary to build an interesting and complex universe. None of which has been created nor destroyed ever since. After billions of years, that raw material combined into ever more complex objects. In the next history post, we will talk about the next level of complexity to emerge; the formation of stars.



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