text: population growth – Digital Insider
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  July 2, 2013 by hb 1 Comment
  After admitting that we cannot yet answer the obvious–and seemingly unanswerable–question about how and why everything began, University of Sydney Professor David Christian begins with the creation of the universe about 13 billion years ago. It's not every historian who would admit, simply:
  About the beginning, we can say nothing with any certainty except that something happened."
  He continues explaining this madness: "We do not know why or how it appeared. We cannot say whether anything existed before. We cannot even say that there was a 'before' or a 'space' for anything to exist in (in an argument anticipated by St. Augustine in the fifth century CE) time and spare may have been created at the same time as matter and energy."
  After that, the big news is not so much the Big Bang Theory (explained here in detail that can be easily understood), but the shift to a neutral electrical charge, enabling the creation of atoms, first simply (mostly, hydrogen and helium atoms), then, in increasingly complicated ways. I like this quote:
  Hydrogen is a light, odorless gas which, given enough time, changes into people."
  Leaping ahead, the sun and the planets show up around 4.56 billion years ago, and, helpfully, Professor Christian helps us to understand an earth bombarded by small planetesimals (excellent word, new to me) and without much atmosphere.
  The early earth would indeed have seemed like a hellish place to humans."
  As the mix of gases shifted from methane and hydrogen sulfide to carbon dioxide, the early atmosphere would have appeared red–that is, the sky would have seemed to be red, not blue. The blue sky came about because the new oceans–made possible by a drop in temperatures below 100 degrees celsius–allowed oceans to form, and those oceans absorbed much of the CO2.
  How about the question of the beginning of life on earth? Again, Christian offers a coherent answer:
  Living organisms are constructed, for the most part, from compounds of hydrogen and carbon. Carbon is critical because of its astonishing flexibility. Add hydrogen, nitrogen, oxygen, phosphorous, and sulfur, and we can account for 99 percent of the dry weight of all organisms. It turns out that when conditions are right and these chemicals are abundant, it is easy to construct simple organic molecules, including amino acids (the building blocks of proteins, the basic structural material of all organisms) and nucleotides (the building blocks of genetic code)."
  Of course, it's one thing to assemble the building blocks and another to assemble these parts into a wooly mammoth, or even an amoeba. Christian admits that this is the tricky part: complexity is the appropriate term that causes contemporary scientists to scratch their heads and wonder. The pieces seem to be there, but the complexity of their union and the spark of life may not be so simple.
  Book: Maps of Time: An Introduction to Big History by David Christian
  Sure, multi-cell animals are interesting footnotes, but really, isn't history all about us? Not exactly, not according to the good professor. Turns out, we are just one of many species, and in the scheme of big history, humans are a kind of, well, a kind of weed. We just keep growing, taking everything over, killing off other species, treating the whole earth as our own private amusement park. Within our lifetimes, there will be 10 billion humans on earth, an astonishing increase given that there were, in 1800, just a billion of us. Every dozen or so years, we add another billion or so.
  As humans began to migrate into Europe and Asia from their original home in Africa, large animals became extinct because we hunted them down, ate them, used their hides for clothing, used their bones for tools. Giant sloths in the Americas, giant wombats and kangaroos in Australia, mammoths in Siberia. We killed them faster than they could reproduce, and so, they're gone.
  So what makes us so special? Is it really all about thumbs? Sure, thumbs make a difference, but it's something else entirely. Professor Christian uses the term "collective learning" to describe our "pooling and sharing of knowledge…the types of knowledge that, over time, have given humans their unique power to manipulate the material world. Two factors stand out: the volume and variety of information being pooled, and the efficiency and speed with which information is shared." Here, he's not referring to the digital age, but the era before we developed any meaningful form of writing, drawing, or communicating with anything resembling a modern language.
  By now, we're about halfway through the book. Next will come the domestication of animals–in which humans figure out that an animal that is killed for its meat is useful only in the short-term, but an animal that is kept alive for its milk is useful in the long-term. This concept of domestication applies not only to meat/milk animals, but to others whose wool, or other production, can be used not only to satisfy basics needs, but also for exchange to other humans. In time, it's the idea of exchange that becomes the driver, resulting first in local trade between tiny settlements, then trade routes as fewer people are tied to subsistence farming or hunting/gathering and more are available (typically, more men are available) for pursuits involving trade, travel, and, in time, the accumulation of wealth.
  Along the way, humans attempt to understand how and why their world works. Since the ground, the soil, the earth provides the food we eat, we begin to explain the world in terms of an earth spirit. Similarly, the sky seems to contain the origins, the mystical, the unknowable, and so, this, too, becomes a kind of spirit. In time–and mostly within a period of just a few thousand years, mostly in southwestern Asia–we gather these beliefs in the form of religions.
  As we, as contemporary, educated humans with every conceivable benefit, attempt to understand our world, and its big history (now a common term combining history and science, by the way), Professor Christian readily admits to what he has done. He has wrapped our beliefs, our knowledge, our stories into what calls "a modern creation myth."
  Filed Under: Books & Print, Learning, Trends Tagged With: atoms, Big Bang Theory, creation myth, David Christian, geography, history, human population, mapping, maps, population growth, Siberia, sloth, wooly mammoth, world history