1 How Much Do We Know about the Universe? ave you ever thought about how to tell the story of the universe from its beginning? Scientists know that the Huniverse began 13.82 billion years ago, give or take a few million years, at a point called the Big Bang. The story needs to cover 13.82 billion years—a big job. What Is Big History? Telling the story from the Big Bang up to the present is called big history. (Other names for this story are journey of the universe, epic of evolution, or cosmic evolution.) Telling this story is like going up on a mountaintop to see the whole landscape laid out below you or out into space to look at the whole Earth. Most of the details are lost to view, but the overall shape comes into sight, a shape that you cannot see from the valley. Big history is an overarching account of the past and present, from the Big Bang until now. People who tell big history are called big historians. Their knowledge and information come from many academic disciplines. They start with astronomy and 1 www.berkshirepublishing.com © 2017 BERKSHIRE PUBLISHING GROUP, all rights reserved. Big History, Small World.indd 1 30/12/16 11:00 am BIG HISTORY, SMALL WORLD physics (atoms, stars, and galaxies), then chemistry (atoms com- bining into elements). Once planets form, they need geology (rocks and their formation). With the beginning of life, they need biology (living organisms). Once humans arrive, they need the disciplines of the humanities—archaeology, anthro- pology, history, philosophy, sociology, and political science. You can see that history on the largest scale includes most dis- ciplines of human knowledge—the ones that try to figure out what happened in the past. It puts together the sciences and the humanities. By the late 1970s and 1980s various university professors around the world began to tell the whole story. They were able to do this because enough empirical knowledge based on experi- mentation and observation had become available. Techniques for dating the age of things had improved dramatically. By 1953 sci- entists had established the age of the Earth (4.5 billion years) and had estimated the age of the universe at 10–20 billion years. By the 1970s the majority of scientists had accepted the idea of plate tectonics—plates of the Earth’s crust move around on semimelted material underneath. This discovery was a key to understanding Earth history. These discoveries made it possible to put together the whole story. In 1989 David Christian, a history professor at Macquarie University in Sydney, Australia, began presenting the story to his class by inviting specialists from other departments in his univer- sity to speak about their part of it. Christian coined the term big history and wrote about his course in an article published in the Journal of World History. The idea of big history began to spread around the world, as a few other professors were attempting sim- ilar courses. 2 www.berkshirepublishing.com © 2017 BERKSHIRE PUBLISHING GROUP, all rights reserved. Big History, Small World.indd 2 30/12/16 11:00 am HOW MUCH DO WE KNOW ABOUT THE UNIVERSE? David Christian: Creator of Big History What kind of person would you expect to come up with the idea and the name of big history? Maybe a college profes- sor of history? A stuffy, pedantic one buried in the library when not teach- ing? Or a cheerful, funny one who likes to perform? Look at the photo of David Chris- tian (b. 1946), and you can probably see that he likes to perform while also being a professor of history at Mac- A cheerful history professor, quarie University in Sydney, Australia. Christian coined the term In November 2013 Christian “big history.” appeared on the Colbert Report. Right off the bat Stephen Colbert said to him: “You attempt to connect wildly diverse things throughout history and really let us get to know the entire history of the universe from the Big Bang to now. Why not something more ambitious?” Christian laughed heartily and replied, “What the course does is teach you the whole history of time. It gives you a map of time and space. If you can place your- self on that map, it gives you a sense of meaning—of where you are and how you came to be.” Christian wasn’t born in Australia, but in Brooklyn, New York, the home of his mother, Carol Cathy Tuttle. His father, John Chris- tian, was English. They met and married in Izmir, Turkey, during World War II, in which his father served as a major in the Brit- ish army during the last year of the war. His mother returned to Brooklyn for David’s birth in 1946. After the war Christian’s father took a job as a colonial officer in Nigeria, where David grew up until he went to boarding school in England when he was seven. David remembers his American mother in rural Nigeria giving him his first exciting lessons. He needed lessons in world history and geography to understand how his parents came together and how the family got to Nigeria. 3 www.berkshirepublishing.com © 2017 BERKSHIRE PUBLISHING GROUP, all rights reserved. Big History, Small World.indd 3 30/12/16 11:00 am BIG HISTORY, SMALL WORLD Christian went to Oxford University in England, then to the University of Western Ontario in Canada, where he met his Ser- bian-American wife, Chardi Randall, who grew up near Port- land, Maine. At the University of Western Ontario, Christian was involved in drama and considered becoming an actor. He returned to Oxford for a Ph.D. in Russian history. He wrote his dissertation about Tsar Alexander I, but he was really more interested in every- day life than in kings and queens. Christian took his first job, teaching Russian history at Mac- quarie University, in 1975. He wrote books about the history of food and drink in Russia, including one about vodka called Living Water. Yet he thought his students needed to know more than Rus- sian/Soviet history. They needed to know the history of humanity as a collective group. To understand where humans came from took him back to the Big Bang. In 1989 the history faculty at Macquarie gave Christian per- mission to try a freshman course beginning at the Big Bang. He invited professors from other departments to talk about their sci- entific fields until he could learn their basic knowledge and put it together into one story. He coined the term big history in 1991. In 2001 Christian began teaching at San Diego State University in California. From there he spread the idea of big history in the United States. In 2009 he moved back to Macquarie University. In 2010 he helped to found the International Big History Association and became its first president. In 2013 he set up the Big History Institute at Macquarie. He directed the Big History Project and now the Big History Institute at Macquarie University. What Is Empirical Knowledge? Big history is based on empirical knowledge, meaning knowledge gained by forming an idea or explanation and then testing it. Sci- entists do this by experimentation and observation; historians do it by checking against established facts. The English word empiri- cal comes from a Greek word meaning “experience.” 4 www.berkshirepublishing.com © 2017 BERKSHIRE PUBLISHING GROUP, all rights reserved. Big History, Small World.indd 4 30/12/16 11:00 am HOW MUCH DO WE KNOW ABOUT THE UNIVERSE? Empirical knowledge develops through what is called the scien- tific method. Empirical knowledge is the dominant form of knowl- edge in the modern world, and scientists around the world use this method. It is based on rigorous, systematic use of carefully tested evidence. It began in the 1600s, when the invention of microscopes and telescopes extended what scientists could observe and when transoceanic shipping made possible global trade and exploration. Scientists may begin by making imaginative guesses. Or they may observe something. They then propose an idea to explain what they have observed, an idea generated by their imagination, intu- ition, and logic. They call this idea a hypothesis. Next, they devise experiments or look for information to test whether the idea can explain the results of their experiments. If it does not, they reject it. If it does, they continue to experiment or look for new information against which to check their ideas, until eventually the hypothesis becomes a theory, with lots of evidence confirming it. A scientific theory is an idea that explains and interprets a lot of facts/data. Scientists continue to call a major idea, like evolution by natu- ral selection, a theory even after so much evidence has accumulated that nonscientists would call it a fact. Scientists are exceedingly careful; they know that new evidence can overthrow major con- cepts. That’s part of the scientific method. Scientists are human and prone to errors and bias, even when they are careful. That’s why they use the scientific method, because with repeated experimentation over time, unbiased conclusions emerge that most people can agree on. By working cooperatively around the world and sharing their data from many perspectives, scientists can reach a reasonable consensus about the nature and workings of the universe, within the limits of the human mind. Here is one example of how science works. It is the story of how the idea of continental drift—the idea that continents move—became the well-established theory of plate tectonics.