Every culture has its own origin story. They may be short anecdotes or elaborate narratives that help explain the mysteries of our existence. “Big History” is an origin story unlike any other. Instead of being rooted in a specific culture or geography, it presents a science-based perspective and is therefore the story of all of humanity. The Big History Project was started by Bill Gates and David Christian to enable the global teaching of what they describe as “the attempt to understand, in a unified way, the history of Cosmos, Earth, Life and Humanity.”
This week, I’d like to present readers with a greatly simplified version of the Big History story in a form that can be shared with children – maybe sitting out in the backyard under a starlit sky. By knowing this story, they will understand that humans are deeply embedded in the natural world and hopefully be inspired to protect the myriad species and habitats with which we co-evolved. Learn the story yourself, and tell it to the children in your life. More information can be found at bighistoryproject.com
Humans are the Universe becoming aware of itself (Photo by Halfblue)
“Tonight, I’m going to tell you the most amazing story you’ve ever heard. And, even better, it’s true. The story is based on everything that science has discovered. Remember, science is the tool we use to find out what’s really true about the world around us. Let’s begin by looking up at the sky and at all those stars. It’s a big Universe out there. Bigger than you or I can possibly imagine. If you’re like me, you can’t help but wonder how and when all of this began. How and why are we here?
This story takes place over 14 billion years, which is an incredibly long time. It would take five human lifetimes to count to 14 billion. So, to make this easier, we’re going to imagine that the story is squeezed into one calendar year. In other words, the story will begin on January 1 and end on December 31.
Let’s get started… In the beginning, there was nothing. There were no humans, no dinosaurs, no rocks, no stars and not even space or time. It’s hard to imagine, isn’t it, but it’s true. Then, all of a sudden, there was a flash of very bright and very hot light. It was like an explosion, but brighter and more powerful than any explosion you or I could ever dream of. It was called ‘The Big Bang’ – the time when the Universe was born. It was January 1 on our time scale.
The Big Bang to the first stars – Wikimedia
At first, all there was heat and light. But, as the Universe began to cool, clouds of tiny particles called atoms began to form. These were the atoms of hydrogen – the main component of water – and helium – the gas we use in party balloons that float on air. Eventually, gravity started compacting these clouds of hydrogen and helium atoms. The temperature at the centre of each cloud grew higher and higher until, suddenly, there was a huge release of energy and Boom! – we had our first stars. Billions of them across the Universe. On our calendar, we are in mid-January.
Now, stars are like people; they are born and eventually die. When very large stars die and explode, they are called supernovae. They become so hot and their gravity so strong that the helium and hydrogen atoms are actually squeezed into new kinds of atoms like oxygen, iron, carbon and even gold. If you are wearing gold jewelry, the gold was made in a supernova explosion. So were all the other atoms in your body except hydrogen. These atoms include the calcium in your bones, the iron in your blood and the oxygen that binds with hydrogen to create the water that you drink.
Take a moment to think about what I just said. These old stars were actually our ancestors. They had to exist so that we could be here. We are made of their dust – stardust! Doesn’t knowing this make you feel like the Universe is a more wonderful place to live in?
Now, with all these different kinds of atoms swirling around younger stars like our Sun, they eventually combined to form asteroids, comets and planets. This is how our solar system and our Earth were formed four and a half billion years ago. On our time scale, we’ve jumped all the way to early September.
As the new planet Earth began to cool, rain fell for the first time and gathered into oceans. Beneath these oceans, at cracks in the ocean floor, heat seeped up from inside the Earth. New chemical reactions began to take place and atoms combined in all sorts of new ways. Some of these combinations were able to make copies of themselves and to eventually form an amazing chemical (molecule) called DNA. It’s the molecule in the genes of all living things. Scientists believe that this is probably how life began. Some think life may also have travelled here from another planet, maybe even Mars. On our time scale, we are now in mid-September.
Structure of the DNA molecule – Wikimedia
One of the most amazing things about DNA is that it’s not perfect. When it copies itself, mistakes sometimes occur. A mistake can have a positive effect, a negative effect or no effect. A positive effect, for example, might give a bird a bigger bill than other members of its species and therefore allow it to survive more easily. This new trait, which will be passed on to its young, can eventually result in whole new species. We call this evolution.
For most of the time of life on Earth, living organisms were very simple. Like present-day bacteria, they were made up of a single cell. However, these cells were still quite complex. Early plant cells, for example, evolved the ability to use the sun’s energy to make food through photosynthesis in which sunlight, water and carbon dioxide (the gas we exhale when we breathe) are converted into sugar and oxygen. On our calendar, this happened in late September.
An artist’s rendition of photosynthesis – Wikimedia
Then, about 700 million years ago (around December 5), living things made up of multiple cells began to appear. In the oceans, animals such as sponges and jellyfish emerged. The first ancestors of insects appeared in mid-December, followed by the first fish. On December 20, the first plants colonized the land when algae (seaweed) evolved ways to survive outside of water. Some of these plants were able to grow into trees when changes in their DNA led to the production of sturdy wood in the stems.
On about December 21, the first true insects appeared. Some, like dragonflies, have hardly changed since. Amphibians, like salamanders, evolved from fish that had developed the ability to crawl out of the water and breathe air. One of these, a fossil called Tiktaalik, was discovered in the Canadian arctic. It is part fish and part amphian. Next, reptiles like turtles appeared on the scene and, by Christmas day, the dinosaurs. The first mammals appeared December 26, the first birds on December 27 and the first plants with flowers on December 28.
An artist’s recreation of what Tiktaalik looked like – Wikimedia
Occasionally, there were disasters. Sixty-five million years ago (December 30 at 6 am on our scale), a 10 kilometre-wide asteroid smashed into the Earth near Mexico. It caused winter-like conditions over the entire planet. For a long time, it was impossible for plants to grow. The dinosaurs were wiped out. Many of our mammal ancestors, however, managed to survive and to flourish in the habitats left empty by the dinosaurs. Through evolution, they changed into many different species.
By late on December 30, some of these mammals had evolved into primates that lived in trees and evolved fingers and toes to hold onto branches. One group of primates, probably looking a little like today’s chimpanzees, learned to walk upright. These were the first primitive humans. They appeared on December 31 – New Year’s Eve – at about 10 pm.
Over time, because of changes in DNA and reasons that we’re just beginning to understand, the human brain tripled in size. With bigger brains, humans were able to develop language and became much better at learning, remembering and passing on information to the next generation. They adopted wolves, which became the dogs we know today. The dogs helped them hunt and provided protection. By eight minutes before midnight on December 31, these early humans looked almost identical to us.
About 70,000 years ago, some humans left the plains of Africa and began migrating to new continents like Europe, Asia and North America. Each migration involved learning — learning new ways of dealing with their surroundings.
Model of Homo erectus – an ancestor of today’s humans – Wikimedia
Then, just 10,000 years ago (18 seconds before midnight) humans learned to farm. With all the food they were able to produce, the human populations got much larger and different groups of humans became more connected to each other. Written language was invented and humans learned to read. At two seconds before midnight, Christopher Columbus traveled to the Americas.
In the last second of our time scale, all of modern history has taken place. With cars, airplanes, radio, phones and now the Internet, humans have become more connected than ever. This has allowed us to learn faster than ever, too. And, in the last 200 years, something else has happened. We stumbled on a cheap, incredibly powerful source of energy in the form of fossil fuels – coal, gas and oil. Fossil fuels and connected learning together explain the modern world we see around us. At the same time, however, burning fossil fuels is changing our climate and making our future less certain. It may be difficult to live as we are now in the climate that is coming.
So, hear we are at the campfire. We’ve been on a journey of almost 14 billion years. Don’t you feel lucky to know the true story of how we humans, along with all the other species and modern civilization came to be here? Where the story goes from here is largely up to us. How will you help?”
