Human Universe

by Professor Brian Cox

  The above might be seen as a naïve rant, of course. One could argue that mutually assured destruction, the guiding principle of the Cold War, did act to stabilise our civilisation and is still doing so today. Perhaps no intelligent beings will knowingly destroy their civilisation, which is what global nuclear war on Earth would surely do; after all, Kennedy and Khrushchev ultimately took this view. Similarly, one assumes that the submersion of Miami and Norwich by rising sea levels would silence the so-called climate change sceptics (I’d call them something different) and trigger a change of policy that will avert catastrophic, civilisation-threatening climate change in good time. It seems to me, however, that a small planet such as Earth cannot continue to support an expanding and flourishing civilisation without a major change in the way we view ourselves. The division into hundreds of countries whose borders and interests are defined by imagined local differences and arbitrary religious dogma, both of which are utterly irrelevant and meaningless on a galactic scale, must surely be addressed if we are to confront global problems such as mutually assured destruction, asteroid threats, climate change, pandemic disease and who knows what else, and flourish beyond the twenty-first century. The very fact that the preceding sentence sounds hopelessly utopian might provide a plausible answer to the Great Silence.

  SO, ARE WE ALONE?

  What, then, is the range of estimates for the number of civilisations in the Milky Way, given the limited evidence we have at our disposal? During the filming of Human Universe, Frank Drake told me that the Green Bank meeting came up with a number of around 10,000, and he sees no reason to change that estimate. This would be wonderful, and makes the search for signals from these civilisations one of the great scientific quests of the twenty-first century. I strongly support SETI, because contact with just one alien civilisation would be the greatest discovery of all time, and it’s worth the investment on that basis alone.

  There is, however, one piece of evidence that might suggest a more lonely position for us on our little home world. In 1966 the mathematician and polymath John von Neumann published a series of lectures entitled ‘Theory of Self-Reproducing Automata’ in which he analysed in great detail the possibility of constructing machines capable of building copies of themselves. Such machines exist in nature, of course – all living things do this routinely. In principle, therefore, one might imagine a sufficiently advanced civilisation building a self-replicating Von Neumann space probe and launching it out to explore the galaxy. On reaching a solar system, the probe would mine the planets, moons and asteroids, extracting the materials necessary to build one or more copies of itself. The newly minted probes would launch themselves out to neighbouring solar systems and repeat the process, spreading across the Milky Way. Even given the vast distances between the stars, computer models assuming currently envisioned rocketry technology suggest that such a strategy could result in the exploration of the entire Milky Way galaxy within a million years.

  Science fiction? It certainly sounds like it, but if there is no objection in principle to the construction of a Von Neumann probe, then one has to develop an argument as to why we don’t see any. The reason that this is difficult to do is due to timescales. The Milky Way has been capable of supporting life for over ten thousand million years. It is possible to envisage many millions of civilisations rising and falling over such vast expanses of time, and if only one had developed a successful Von Neumann probe, then the galaxy should be filled with its progeny; there should be at least one Von Neumann probe operating in our solar system today. Carl Sagan and the astronomer William Newman noticed a flaw in this line of argument. If the probes multiply exponentially and unchecked, then one can show that they consume the resources of the entire galaxy relatively quickly, and we’d certainly have noticed that! Or more accurately, we wouldn’t be here to notice that. Sagan reasoned that this obvious risk would be sufficient to prevent any civilisation intelligent enough to build Von Neumann probes from actually doing so. They would be doomsday machines. Other astronomers have countered that it wouldn’t be beyond the wit of such an advanced intellect to build in some fail-safe mechanism that guaranteed, for example, only one probe per solar system, or a finite lifetime for each probe. Others have argued that there may indeed be a Von Neumann probe operating in our solar system today, with appropriate fail-safe mechanisms installed to stop it eating everything. If such a probe were relatively small, perhaps sitting amongst the asteroids or even in the Kuiper Belt of icy comets beyond the orbit of Neptune, then we’d almost certainly be unaware of its presence.

  Von Neumann probes wouldn’t be the only signatures of ultra-advanced civilisations. Imagine a civilisation many millions of years ahead of us, carrying out engineering projects on a galactic scale. Imagine interstellar starships or great space colonies constructed in otherwise uninhabitable solar systems. Why not? As I said at the start of this chapter, we went from the Wright Brothers to the Moon in a single human lifetime, so, I ask again, how far will we travel, if the laws of physics allow, given another thousand years? Or ten thousand? Or a million? What signature will we leave on the sky if we survive and prosper that long? None of these questions is trivial, because the sheer immensity of the timescales available for life to evolve in the Milky Way galaxy forces us to consider them. Why should we be the most advanced civilisation in the galaxy when we’ve only been building spacecraft for half a century in a 13-billion-year-old universe? I don’t have an answer to this. It bothers me. Perhaps the distances between the stars are indeed too great, or perhaps there are insurmountable difficulties in building self-replicating machines or starships, but I can’t think what they might be.

  I am tempted, therefore, to make the following argument for the purposes of debate. I think that advanced, space-faring civilisations are extremely rare, not because of astronomy, but because of biology. I think the fact that it took almost four billion years for a civilisation to appear on Earth is important. This is a third of the age of the universe, which is a very long time. Coupled with the remarkable contingency of the evolution of the eukaryotic cell and oxygenic photosynthesis – not to mention the half a billion years from the Cambrian explosion to the very recent emergence of Homo sapiens and civilisation – I think this implies that technological civilisations are stupendously rare, colossally fortuitous accidents that happen on average in much fewer than one in every two hundred billion solar systems. This is my resolution to the Fermi Paradox. We are the first civilisation to emerge in the Milky Way, and we are alone. That is my opinion, and given our cavalier disregard for our own safety, it terrifies me. What do you think?

  WHO ARE WE?

  But why, some say, the moon?

  Why choose this as our goal?

  And they may well ask why climb the highest mountain?

  Why, 35 years ago, fly the Atlantic? …

  We choose to go to the moon.

  President John F. Kennedy

  SPACEMAN

  Astronaut John Young was once asked how he would feel if his epitaph read ‘John Young: The Ultimate Explorer’. Young smiled, and in a test pilot’s drawl replied, ‘I’d feel sorry for the guy who wrote it’. Young was, and still is, a hero of mine. My first vivid memory of live space exploration was watching Space Shuttle Columbia climb on a tower of bright vapour into a blue Cape sky on 12 April 1981. It was midday in Manchester, the Easter holidays, and I was 13 years old. Because of a two-day launch delay, Columbia’s test flight took place precisely 20 years to the day after Yuri Gagarin made his black-and-white voyage into orbit on 12 April 1961, but Young and his co-pilot, Bob Crippen, in their orange spacesuits, were astronauts from the colour age, the future – as distant from the Russian hero as gleaming white-winged Columbia was from Vostok 1. Equidistant from both was Apollo, which Young flew to the Moon. Twice. It was the age of optimism, the age of wonder, the golden age when the ape went into space. When unflappable aviator Young, whose pulse rate did not increase during the launch of NASA’s only manned spacecraft ev
er to have flown without an unmanned test flight, piloted Columbia back for a flawless manual landing at Edwards Air Force Base two days later, he turned to Crippen and said ‘We’re not too far away – the human race isn’t – from going to the stars’.

  In 2014 the stars feel further away than they did in 1981; the International Space Station is a wonderful piece of engineering that has allowed us to learn how to live and work in near-Earth orbit, but it is no closer to the stars than Columbia. Its construction is no mean achievement; one of the most important things to realise about engineering at the edge is that the only way to learn is to actually do it. You can’t think your way into space; you have to fly there. But I can’t help but feel, in the words of Billy Bragg, that the space race is over and we’ve all grown up too soon.

  It was different in Gagarin’s day. Nobody is born to be a spaceman. We’re apes, honed by natural selection to operate in the Great Rift Valley. Gagarin’s father was a carpenter and his mother was a milkmaid. Both worked on a collective farm. Gagarin’s first job at the age of 16 was in a steel mill, but after showing an aptitude for flight as an air cadet he joined the military when 21 and was posted to the First Chkalovsk Air Force Pilots School in Orenburg. Rising through the ranks, he made a name for himself as a skilled and intelligent aviator, and in early 1960 he was chosen along with 19 other elite pilots for the newly established space programme. Standing just 5 foot 2 inches tall, Gagarin had the right stuff and was perfect for the tiny Vostok spacecraft, whose single-seat crew compartment was only 2.3m in external diameter. After a year of training, Nikolai Kamanin, head of the cosmonaut programme, chose Gagarin ahead of his rival, Gherman Titov, just four days before the flight. The history books are filled with the names of great men and women whose presence in the collective memory of humanity was assured by the slimmest of margins. Gagarin, alongside Armstrong, will be remembered for as long as there are humans in the cosmos; the name of the equally brilliant Titov, Russia’s second cosmonaut, has faded away.

  Gagarin’s flight was a true journey into the unknown. Strapped on top of the Vostok-K rocket, which flew 13 times and made it into space on 11 occasions, the 27-year-old performed like a true test pilot. Despite a two-hour delay during which every component of the spacecraft hatch was taken apart and rebuilt while Gagarin remained strapped into his seat, his heart rate was recorded at 64 beats per minute just before launch. This is not to say that Gagarin wasn’t fully aware of what he was about to do. Before boarding, Gagarin made one of the great speeches of the age.

  ‘Dear friends, both known and unknown to me, fellow Russians, and people of all countries and continents, in a few minutes a mighty spaceship will carry me into the far-away expanses of space. What can I say to you in these last minutes before the start? At this instant, the whole of my life seems to be condensed into one wonderful moment. Everything I have experienced and done till now has been in preparation for this moment. You must realise that it is hard to express my feeling now that the test for which we have been training long and passionately is at hand. I don’t have to tell you what I felt when it was suggested that I should make this flight, the first in history. Was it joy? No, it was something more than that. Pride? No, it was not just pride. I felt great happiness. To be the first to enter the cosmos, to engage single-handed in an unprecedented duel with nature – could anyone dream of anything greater than that? But immediately after that I thought of the tremendous responsibility I bore: to be the first to do what generations of people had dreamed of; to be the first to pave the way into space for mankind. This responsibility is not toward one person, not toward a few dozen, not toward a group. It is a responsibility toward all mankind – toward its present and its future. Am I happy as I set off on this space flight? Of course I’m happy. After all, in all times and epochs the greatest happiness for man has been to take part in new discoveries. It is a matter of minutes now before the start. I say to you, “Until we meet again”, dear friends, just as people say to each other when setting out on a long journey. I would like very much to embrace you all, people known and unknown to me, close friends and strangers alike. See you soon!’

  It’s too easy to attach trite labels to human actions – magnificent, horrific and everything in between – based on a simplified view of their causes. One can argue that the rockets carried aloft the egos of the superpowers alongside the astronauts, and this is surely right. But Gagarin spoke these words, and I challenge anyone to read them and not detect sincerity. All our actions mask a morass of motivations, worthy and less so, and the greatest human adventures are no less noble for that.

  At 9.07am local time, Gagarin blasted off from Baikonur Cosmodrome in Kazakhstan, as every Russian cosmonaut has done since. Within 10 minutes, he was orbiting Earth at an altitude of 380 kilometres. His route took him across the Siberian wastes and the Pacific Ocean above the Hawaiian islands, past the tip of South America and into the South Atlantic, where he was greeted by a second sunrise before a 42-second de-orbit burn over the Angolan coast slowed Vostok 1 into a parabolic orbit and an 8-g deceleration inside Earth’s thickening atmosphere. The journey once around his home world took 1 hour and 48 minutes. Gagarin ejected from the capsule 7 kilometres above ground and, as planned, cosmonaut and spacecraft completed the final descent apart. Gliding back to Earth by parachute, Gagarin landed 280 kilometres away from the intended landing site near the Russian city of Engels. Dressed in orange spacesuit and white helmet, a farmer and his daughter bore sole witness to his historic return. ‘When they saw me in my space suit and the parachute dragging alongside as I walked, they started to back away in fear,’ recollected Gagarin later. ‘I told them, don’t be afraid, I am a Soviet citizen like you, who has descended from space and I must find a telephone to call Moscow!’

  APEMAN

  Primates appeared relatively recently in the history of life on Earth. Studies of mitochondrial DNA suggest the Strepsirrhini suborder, containing the ancestors of Madagascar’s lemurs, diverged from our own Haplorhini suborder approximately 64 million years ago, which implies that a common ancestor was present before this time, but not a great deal earlier. The first complete primate fossil found to date is that of a tree-dwelling creature known as Archicebus achilles, dated at 55 million years old. Discovered in the fossil beds of central China in 2013, this tiny creature would have been no bigger than a human hand, making it not only the oldest but also one of the smallest known primates.

  Our family, known as the Hominidae, or more commonly the great apes, share a common ancestor with Old World monkeys around 25 million years ago, and during the making of Human Universe we filmed a rare species of these distant cousins in the Ethiopian Highlands. The road out of Addis towards the 3000-metre Guassa Plateau is excellent to a point, and then not excellent. The scenery, on the other hand, improves with altitude. Golden grasses illuminated by shifting lambent light through dark clouds cling to near-vertical mountainsides framing pristine villages along the high valley floors. It is fresh, cold and insect-less on the peaks above the Rift; a place to drink tea and eat shiro, a spiced Ethiopian stew of chickpeas and lentils. After a night in the cold but magnificently desolate Guassa community lodge, we set off at dawn to intercept the gelada baboons on their way back to their caves and ledges from early-morning foraging expeditions on the higher slopes.

  The gelada baboons are a species of Old World monkey found only in the Ethiopian Highlands. They are the only surviving species of the genus Theropithecus that once thrived across Africa and into Southern Europe and India. The males in particular are powerful, long-haired animals, weighing over 20 kilograms with a bright red flash of skin on their white chests. I was told not to look them in the eye, so I didn’t. Fifty thousand years ago, as our planet emerged from the last ice age, the gelada retreated into the highlands above the Rift where they still live, uniquely amongst extant primates, as graminivores, on a diet made up almost entirely of the tough high-altitude grasses and occasional herbs.

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  EVOLUTION OF HOMINIDS

  These hominid evolutionary trees trace our genetic history as humans to the Old World monkeys that roamed Earth 25 million years ago. Discoveries of various remains, including those of the famous Australopithecus afarensis skeleton, commonly called Lucy, have helped us piece together an idea of our ancestry. It is believed that around 7 or 8 million years ago we split from the chimpanzees and the process of evolution into bipedal Homo sapiens began as these monkeys started to spend more time on the ground than in the trees.

  EVOLUTIONARY TREE OF MONKEYS AND PRIMATES

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  They approach with nonchalant agility in small groups, which reflect the most complex social structure of any non-human primate. Most of the groups I saw contained one or two males and perhaps eight or ten females and their young. These are referred to as reproductive units, and clearly defined hierarchies exist within them. Females usually remain in the same unit for life, but males move between them every four or five years. There are also male-only units of ten or fifteen individuals. These social units are arranged into higher groupings known as bands, herds and communities. The community we encountered numbered several hundred individuals who wandered past in their little tribes, females and young pausing to eat, groom and play whilst the larger males eyed us closely.