Earth has existed for 4.5-ish billion years, as far as we can tell. 4.5 billion. It’s a timescale that can only really be thought about in the abstract; you can know it, but not really comprehend it. You can hear of an event that happened a week ago, or a month ago, or ten or one hundred or one thousand years ago, and have an intuitive understanding of about how much time that is, of what it might have felt like to experience the passage of that time, of the things that might have happened and changes that might have occurred over the course of that time. Not so for a million, or a billion, or four and a half billion. The human brain is not built to think in those terms. A billion years may as well be a million years as far as our thinkmeat is concerned. If you want to get even a vague feeling of the colossal time scales we’re talking about here, you have to cheat a bit. You have to break it down into units, establish frames of reference, train yourself to think about it in a relatable way. It’s a bit like learning to read a map.
Because we’re humans, human history is the best frame of reference to start with. Humans probably learned how to make fire about 1.3 million years ago; this is an arbitrary and arguably wrong place to start ‘human history’, but it’s the one I’ve chosen to use and it’s my post, so deal with it. Between 1.3 million years ago and today is…everything else. The evolution of anatomically modern humans (the humans to first tame fire were a different species, homo erectus, long before modern humans existed), the development of spoken language, the invention of agriculture, metalworking, and damn near every other thing humans have ever invented, all of it happened within that 1.3 million year timespan. Let’s write that out in numbers: 1,300,000. Agriculture, and with it the beginnings of what we might term ‘civilization’, was independently developed in different places all over the world over a period about 15,000 to 12,000 years ago. Now we’re getting closer to a human-comprehensible timespan, although we’re not quite there yet. Around 10,000 to 8,000 years ago, the first large-scale permanent human settlements are attested in the archaeological records, villages which over thousands of years gradually evolved into the first proto-cities. The oldest known continuously-inhabited communities in the world today are in Lebanon, Syria, and Palestine, and have been continuously inhabited since about 9,000 years ago, give or take. Now let’s narrow ourselves down from ‘the sum total of human history’ as arbitrarily defined by me, to ‘the history of human civilization’ as also arbitrarily defined by me. Let’s say human civilization started with the settlement of the oldest extant continuously-inhabited communities – this definition is wrong for multiple reasons, but it gives us some nice concrete numbers to work with.
Nine thousand-ish years, then. Still a difficult amount of time to comprehend. The sum total of all written history fits into less than half of that. All of the myths and legends, the histories, the stories, all the truth and fiction that has ever been penned comes from that little span of time. It encompasses the rise and fall of a thousand nations, and the lives of over 90% of all the anatomically modern humans who have ever lived according to some estimates (as a fun little aside, the people alive today are about 7-8% of all the humans who have ever lived). In numerals, it looks like this: 9,000
So, 4,500,000,000 is the rough age of the Earth, rounded to the nearest hundred million for convenience. 1,300,000 is the number of years between the taming of fire and now, rounded to the nearest hundred thousand. 9,000 is the number of years between the settlement of the oldest currently existing human communities and now, rounded to the nearest thousand. Between the formation of the Earth and the controlled use of fire by humans were 4,498,700,000 years. Between the controlled use of fire and the settlement of the first proto-cities were 1,291,000 years. The period of time between the discovery of fire and today is 0.029% of the Earth’s total age. The period of time between the settlement of the first proto-cities and today is 0.7% of the time between the discovery of fire and today, and 0.0002% of the Earth’s total age.
Imagine there is a theater playing a film on a loop. It plays continuously and visitors can come and go as they please, sit down and watch however much of the film they like. The film is a timelapse of the entire history of the Earth. The timelapse is running at such a speed that the entire history of human civilization takes about two hours to watch, from the earliest settlement of Jericho to today, meaning a rate of about 75 years per minute. Assuming the film ran continuously, 24/7/365, the looping movie would reach this segment once every 416 days or so. Two hours of recorded human history would be preceded by over a year of timelapse footage, over half of which would be of essentially nothing. When you celebrate the new year, the film begins. At Easter, the film is playing. When Thanksgiving and Christmas roll around, the film is playing. You celebrate another New Year, and still the film is playing. Finally, in early March of the second year, it reaches the founding of the first cities, and before you know it, in so little time that you might not even be able to make an entire date night out of it, it’s over. The history of human civilization is the rough temporal equivalent of one movie night in a period of over 13 months.
If you’re feeling a bit anxious thinking about it right now, as I am, it’s because you are staring into a bottomless pit. This is deep time. If you were to hitch up a line and descend into that pit, humanity and all its works would quickly disappear from view, and you would continue to descend, deeper and deeper, miles and miles, the light of the present receding to a distant pinprick. Eventually, nearly halfway down, etched into the pit’s walls, you would find the opening line of our story. Oh, I forgot to mention that, didn’t I? There’s a story to be told here, and this thing you’re reading right now is the prologue. It’s a true story, and one which I can’t claim to have written; in fact, nobody wrote it. The story wrote itself. I merely read it, and now I am recounting it to the best of my ability. It starts something like this:
1.5 billion years ago, somewhere on the ancient continent of Columbia, a volcano erupted.
