FARMING: THE BEDROCK OF CIVILISATION
There are many competing theories as to the reason for the domestication of crops, but many note the correlation between the first evidence of agriculture and the beginning of the current inter-glacial period known as the Holocene, 12,000 years ago. In the fertile crescent around modern-day Jordan and Syria, people known as the Natufians were beginning to settle into larger communities, perhaps because of the relatively benign climate. The area would have been forested and rich in wild cereals, fruits and nuts, rather than the austere desert of today. One theory is that a brief 1000-year cold period known as the Younger Dryas, beginning around 10,800 BCE, triggered drier conditions in the region, forcing the Natufians to begin cultivating the previously abundant wild crops on which they had come to rely. Whatever the reason, it is generally agreed that the foundational crops of modern agriculture, including wheat, barley, peas and lentils, were all to be found in the Fertile Crescent by 9000 BCE, and by 8000 BCE the banks of the Nile were being cultivated.
At approximately the same time, evidence of farming can be found in Asia’s Indus Valley, in China and in Mesoamerica. This suggests that there was no single environmental or developmental cause for agriculture, because it appeared independently at many sites across the world. Rather, our large brains and relatively large social groups were ready to take up the challenge when the need arose.
Once agriculture was established, larger numbers of people could live together, taking advantage of the more stable food supply. The freedom from continual hunting and gathering would have introduced a new aspect to human life – free time – and it was used to great effect. Some of the earliest farmers settled in a place known as Beidha in modern-day Jordan around 7000 BCE. Living in round, stone-built houses, they grew barley and wheat and kept domesticated goats, engaged in ritual and ceremony and buried their dead. Importantly, each of these activities was carried out in specific areas of the settlements: the beginning of ‘town planning’. By the second century BCE a Semitic people known as the Nabataeans lived around Beidha. They employed new technologies to increase the reliability of farming and constructed walled agricultural terraces on the hillsides around the village to collect and store water. Animal husbandry was also expanding, with the domestication of cows, pigs, donkeys and horses. Even previously dangerous animals were coerced into living with humans; there is evidence that the Nabataeans kept dogs. As the great empires of Egypt, Greece and Rome prospered, the Nabataeans remained partially nomadic, driving their camel trains across the desert along the long-established trade routes between North Africa and India and the great cities of the Mediterranean. But then, around 150 BCE, they decided to try something different. A few kilometres south of Beidha, in a narrow gorge naturally formed in the soft sandstone rock, they built the city of Petra.
Today tourists stream through a magnificent passageway lined with buildings carved out of the desert rocks and known as the Siq, but 2000 years ago the great and good of Mesopotamia, Rome and Egypt would have walked this route into this jewel of late antiquity.
The grandeur of the buildings is still overwhelming; they stand not as great architecture for their time, but as simply great, with no caveat. The most famous is called Al Khazneh, which means ‘Treasure Box’, because of the carved urn above the entrance which, Bedouin legend has it, contains the treasure of a Pharaoh. Monumental architecture is a common feature in the rise of human civilisation. It is a statement of power and grandeur to impress and cow outsiders, but it also serves an internal purpose, cementing the position of the rulers in the hierarchy and therefore providing the stability and security on which civilisation rests. Over time, a virtuous circle emerges: the buildings help the civilisation prosper, and the more prosperous the civilisation, the more impressive the buildings become.
Petra’s wealth was derived from its location. Built within a natural gorge, the area is prone to flash floods, which provided precious water in a landscape that was arid by the time the Nabataeans began to build. The city also sits at the fulcrum of the ancient nomadic trade routes along which wood, spices, incense and dyes were transported from Africa and India and into the great Mediterranean civilisation beyond. The appetite of the Greeks and Romans for exotic goods was insatiable; black pepper alone fetched 40 times its own weight in gold in a Roman market. Petra, because of its strategic location, controlled all that trade and taxed it. Today, 1500 years after the city was abandoned, it is still a magnificent site – an overused but entirely accurate statement. Talk to an archaeologist, however, and you quickly realise how much more impressive it would have been in its hey-day. The hillsides running down the valley from the carved tombs are scattered with rocks, but closer inspection reveals them to be bricks, the remains of houses, temples and palaces. Everything from Al Khazneh to the houses would have been covered in white plaster and painted in bright colours which would have appeared resplendent against the monochrome desert sands.
To build on this scale required a huge labour force; Petra was home to at least thirty thousand people living in a few square kilometres of desert. Such a population density required technological innovation on a metropolitan scale, and the Nabataeans, perhaps more than any other civilisation in antiquity, were masters of fluid engineering. Virtually every drop of rainwater that fell on the surrounding hillsides was captured in grooves and stored in giant reservoirs and cisterns. They were better at plumbing than the Romans, who employed the Petran engineers in Rome. Petra had the world’s first pressurised water system, which could deliver 12 million gallons of water a day into the city.
Outside the city, the irrigation system continued out into the surrounding fields, lining the hillsides in still-visible terraces; the Nabataeans didn’t simply build a city, they terra-formed a landscape. I stood and imagined the ancient valley views with some awe; the mountain slopes would have been green with maize, barley, pulses and vineyards – a desert turned green and feeding this grandest of desert civilisations for six centuries. Whenever I see the ruins of Petra, Rome, Athens or Cairo, I wonder what Earth would be like today if the great civilisations of antiquity had not fallen. I blame the philosophers for not discovering the scientific method earlier and inventing the electric motor. How hard can it be?
Agriculture, then, was fundamentally important to the rise of civilisation because it enabled large numbers of people to live in one place, and gave them access to resources and time, which would have been unavailable to hunter-gatherers. With resources and time comes the division of labour, freeing up a small but important subset of individuals to engage in pursuits other than those necessary for immediate survival. Farmers, stonemasons, priests, soldiers, administrators and artisans emerge, together with a ruling class who begin to direct the construction of monumental architecture, partly for their own selfish ends. And cities like Petra become possible.
Petra was a relative latecomer in the emergence of the cities and civilisations of antiquity. The first great ancient civilisation, the Old Kingdom of Egypt, arose around 2600 BCE along the fertile and farmed banks of the Nile, and precisely the same pattern of agriculture, followed by social stratification, ritual and monumental architecture, can be seen. Present also in the Old Kingdom, and possibly developed there, was the one final vitally important innovation we will soon discuss: the written word.
THE KAZAK ADVENTURE: PART 1
It all seemed so simple when written down on a piece of paper. The BBC prepares something known as a call sheet, which tells a film crew everything they need to know about a trip. Call sheets are very neat; all the timings work beautifully, carefully documenting flights, ground transfers to locations and filming and rest periods, all of course in accordance with health and safety regulations and all that. Things never quite work out the way they’re envisaged back in the office, of course, but filming the return of the Expedition 38 crew from the International Space Station to the Kazak Steppe in March 2014 was the wildest adventure I’ve experienced.
The call sheet said that we would fly into Astana on 8 March, arriving at 1am on the 9th into our hotel. After a leisurely breakfast at 9am, we’d drive to a city called Karaganda, which has a spectacular statue of Yuri Gagarin in the town square. There, we’d meet up with our drivers who, embedded with Roscosmos, the Russian space agency, would drive us out to the landing site the following morning, arriving in time for a ‘hot meal’ and a good rest on the Steppe, ready to film the landing on the morning of the 11th after, of course, a ‘hot breakfast’. We’d then drive back to the airport, hop on a flight, and be home in time for lunch on the 12th. A doddle. Bollocks.
The Steppe of central Kazakhstan in March is a featureless frozen wilderness covering around 800,000 square kilometres of the country’s interior. There are no towns and few roads; just tufts of stunted brown grass and snow fading into an ice-grey leaden sky. In March 2014 temperatures were unseasonably cold, falling below -20°C at night, and it was snowing. Our team had standard 4×4 vehicles, which got stuck in the snow by mid-afternoon the day before the landing, even though we’d set off three hours earlier than the 6am officially sanctioned health and safety call time because of the weather. This was problematic, because our ‘ApeMan SpaceMan’ film was constructed carefully around this moment – the return of three human beings from space. Over vodka, cold meat and bread, we discussed our options.
We’d been helped along the snowy roads by a Russian team from the Siberian city of Tobolsk in two spectacular 6-wheel-drive vehicles, hand-built by a company called Petrovich. Tobolsk is best known for being the place dissidents were sent during the Soviet era. Tsar Nicholas II and his family enjoyed the Tobolskian hospitality for a year before being transported to Ekaterinburg to be shot. Mendeleev, the inventor of the Periodic Table, was born there, but so was Rasputin. It’s a tough place, and they know how to build tough vehicles. Our guide from Roscosmos managed to radio the Petrovich team, and they agreed that if we could catch them up in the frozen wilderness, they could take two of us out to the landing site. The cameraman and I jumped aboard a pair of snowmobiles, and headed out into the rapidly dimming late-afternoon twilight in search of the men from Siberia. If we hadn’t found them, then presumably you wouldn’t be reading this, but we did.
It was a difficult decision to jump onto the snowmobiles. We didn’t have a satellite phone because they are illegal in Kazakhstan, and nobody spoke English so we couldn’t quite assess the level of difficulty associated with finding these two Siberian needles in a Kazak Steppe. And we didn’t know who the Siberians actually were. It seemed that they were freelancers, hired to take photographs and broadcast live television pictures back from the landing site for the Russian space agency. We also had to decide whether we could make the film with only two people. Much as I spend a lot of time dreaming about jettisoning directors, producers and executives, there is a reason why we usually take a crew of six. Sound is particularly important; you don’t really miss the soundman until he’s not there (our soundman on the series is called Andy, but we always called him soundman – there are too many other things to remember).
As it turned out, the Petrovich crew were a hospitable and professional bunch, although their willingness to spend many days out in the wilderness waiting for the Soyuz – they’d driven down from Siberia and were in no hurry to get home – played on our minds. Approaching midnight on the night before the landing, we received a message from Roscosmos that the landing might be postponed due to the poor weather, and the decision was made to camp out on the Steppe and wait. In the distance, we could make out a small group of farm buildings through the snow, and we headed towards them. In broken English, one of the crew told us that it is a Kazak tradition to welcome travellers into your home, at any time of the day or night, and offer them food. And so we found ourselves inside a farm house that appeared to have heated walls and resembled the inside of an oven, eating a feast of jam, bread, assorted sweets and horse, all washed down with vodka, which the Petrovich crew carried in large crates alongside their satellite broadcasting hardware. It was unforgettable. Human Universe was filmed as a love letter to the human race, and time and again when I’ve found myself immersed unexpectedly in a culture, I’ve been reminded about why it is appropriate to want to write one.
At 4am, soaked in vodka, the call came through. Commander Oleg Kotov, Sergey Ryazansky and Mike Hopkins had climbed aboard the Soyuz and were preparing to depart the International Space Station. I was elated, because I genuinely thought the landing would be called off, and I had no idea what that would have meant, other than waiting for the storms to clear on the Steppe.
At 6.02am Kazak time, the Soyuz TMA-10M, the 199th Soyuz to fly since 1967, undocked from the ISS. This is the point of no return, except in an emergency. Just 2 hours and 28 minutes later, it fired its engine for a pre-programmed burn of 4 minutes and 44 seconds. This reduced the spacecraft’s velocity by 128m/s relative to the Station, which in its orbit that day was travelling at 7358m/s. That number is not arbitrary. It is given by a simple equation which can be derived easily from Newton’s Law of Gravitation and his Second Law of Motion, F=ma. We leave it as an exercise for the reader to show that these two laws of nature can be rearranged to show that the velocity v of any object in a circular orbit a distance r from the centre of the Earth, mass Me, is given by
To derive this result, you need to know that the force required to maintain an object of mass m in a circular orbit is mv2/r.
The Space Station orbits at an altitude of between 330 and 445 kilometres – let’s choose the middle ground of 387 kilometres – this is a back-of-the-envelope calculation. ‘Estimate is the name of the game’, as my old physics teacher used to say at school. The radius of the Earth is 6,378 kilometres, and the mass of the Earth is 5.97219 × 1024 kg. Newton’s gravitational constant is 6.67384 × 10-11 m3 kg-1 s-2. Do the calculation yourself; maths is good for you. With these numbers, v is approximately 7675m/s, which is close enough – the difference is due to the precise altitude of the ISS that day. I love doing little calculations like this. They reveal the immense power of mathematical physics; this really is the orbital velocity of the International Space Station, and it is forced to be so by laws of nature first published by Isaac Newton in 1687. If you’ve never done a calculation like this before, you should feel elated. The biologist Edward O. Wilson called this feeling the Ionian Enchantment, a poetic term he introduced to describe the realisation, credited to Thales of Miletus in 600 BCE, that the natural world is orderly and simple, and can be described with great economy by a small set of laws. It is nothing short of wonderful that we can calculate the orbital velocity of the International Space Station together in a few lines of a popular book, and this points us neatly towards the story of the last great innovation in the ascent from apeman to spaceman: the written word.
INTERMISSION: BEYOND MEMORY
I began my degree at the University of Manchester in 1992, which is when I started doing physics full time. I gained my PhD in 1998, and spent the next eleven years working as a particle physicist at the DESY laboratory in Hamburg, Fermilab in Chicago and CERN in Geneva. In 2009 I began filming Wonders of the Solar System, which slowed down my research a bit. But I’ve been at it now for 22 years, which is almost half my life. In that time, I’ve learnt a lot about how to be a scientist, how to think about scientific problems, how to make measurements of nature, particularly the behaviour of subatomic particles, and how to interpret those measurements to generate new knowledge and make new discoveries. But given all that, there is no way that I would be able to calculate the orbital velocity of the International Space Station from scratch. Given Newton’s laws, it’s trivial. Without them, it would be virtually impossible. Newton’s laws are far from obvious; they took Newton a scientific lifetime to produce, and he was a genius – one of the greatest scientific minds of all time. And even he didn’t start from scratch. He relied heavily on the previous works of Galileo, Euclid and a hundred other philosophers, geometers and mathematici
ans whose names have been forgotten but whose works remain as cornerstones of our scientific culture. The reason we could run through that simple calculation together is that the thoughts and discoveries of these generations of philosophers, scientists and mathematicians were not lost; they were preserved forever in the written word.
Writing appears to have arisen independently in several different cultures, just as with the development of agriculture, and just as agriculture triggered the birth of civilisation 12,000 years ago, so the emergence of writing supported a rapid increase in the complexity of civilisation. The earliest known system of writing is generally accepted to be cuneiform, the Sumerian system that emerged around 5000 years ago in the cities of Mesopotamia, although it is possible that Egyptian hieroglyphs may predate it. Literally meaning ‘wedge-shaped’, cuneiform comprises a thousand or more symbols created using a stylus made from reed that was pressed into a soft clay tablet. Following cuneiform and hieroglyphs, other forms of script emerged in Greece, China, India and, later, Central America.
Writing seems not to have arisen out of a deep human need to share and record intimate thoughts and lay down knowledge for future generations; that would be far too romantic. Rather, it appears to have served a more practical purpose, revealed in a set of around 150 Nabataean scrolls discovered by archaeologists in 1993. The scrolls date from around 550 ce, in the final period before Petra was abandoned. One of the most intact documents relates to a court case between two priests. It is alleged that one of the priests decided to run away from their shared house, taking a key to one of the upstairs rooms, two wooden beams that presumably held the roof up, six birds and a table. This is probably how writing began; the invention upon which modern human history rests arose, disappointingly, for admin purposes. This is seen not only in the relatively late Nabataean scrolls, but in many of the early texts. Cuneiform developed because of a need to keep track of trade and accounts in the increasingly complex economy of Mesopotamia. Egyptian hieroglyphs may be an exception, as there is a strong ritual component, but there is also evidence of their early use in commerce, administration, trade and law – the foundations of a modern society. Information about the natural world was also recorded; in hieroglyphs we see the cycle of the seasons chronicled, as well as important environmental events. There are also some beautiful early examples of the use of writing to express deeper human desires and feelings that resonate strongly today and show, yet again, that our ancestors had inner lives not too distant to our own. But the oldest surviving papyrus documents from the Old Kingdom are marvellously prosaic. From Dynasty 5, in the reign of Pharaoh Djedkare-Izezi between 2437 and 2393 BCE, can be found an early version of the parrot sketch.
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