Human Universe. Andrew Cohen

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СКАЧАТЬ way through the 1970s, I learned my place amongst the continents and oceans of our blue planet. I could tell you about polar bears on Arctic ice flows or gazelle grazing on central plains long before I physically left our shores. I discovered that our Earth is one planet amongst nine (now redefined as eight) tracing out an elliptical orbit around an average star, with Mercury and Venus on the inside and Mars, Jupiter, Saturn, Uranus and Neptune beyond. The Sun is one star amongst 400 billion in the Milky Way Galaxy, itself just one galaxy amongst 350 billion in the observable universe. Later, at university, I discovered that physical reality extends way beyond the 90-billion-light-year visible sphere into – if I had to guess based on my 46-year immersion in the combined knowledge of human civilisation – infinity.

      This is my ascent into insignificance; a road travelled by many and yet one that remains intensely personal to each individual who takes it. The routes we follow through the ever-growing landscape of human knowledge are chaotic; the delayed turn of a page in a stumbled-upon book can lead to a lifetime of exploration. But there are common themes amongst our disparate intellectual journeys, and the relentless relegation from centre stage that inevitably followed the development of modern astronomy has had a powerful effect on our shared experience. I am certain that the voyage from the centre of creation to an infinitesimally tiny speck should be termed an ascent, the most glorious intellectual climb. Of course, I also recognise that there are many who have struggled – and continue to struggle – with such a dizzying physical relegation.

      John Updike once wrote that ‘Astronomy is what we have now instead of theology. The terrors are less, but the comforts are nil’. For me, the choice between fear and elation is a matter of perspective, and it is a central aim of this book to make the case for elation. This may appear at first sight to be a difficult challenge – the very title Human Universe appears to demonstrate an unjustifiable solipsism. How can a possibly infinite reality be viewed through the prism of a bunch of biological machines temporarily inhabiting a mote of dust? My answer to that is that Human Universe is a love letter to humanity, because our mote of dust is the only place where love certainly exists.

      This sounds like a return to the anthropocentric vision we held for so long, and which science has done so much to destroy in a million humble cuts. Perhaps. But let me offer an alternative view. There is only one corner of the universe where we know for sure that the laws of nature have conspired to produce a species capable of transcending the physical bounds of a single life and developing a library of knowledge beyond the capacity of a million individual brains which contains a precise description of our location in space and time. We know our place, and that makes us valuable and, at least in our local cosmic neighbourhood, unique. We don’t know how far we would have to travel to find another such island of understanding, but it is surely a long long way. This makes the human race worth celebrating, our library worth nurturing, and our existence worth protecting.

      Building on these ideas, my view is that we humans represent an isolated island of meaning in a meaningless universe, and I should immediately clarify what I mean by meaningless. I see no reason for the existence of the universe in a teleological sense; there is surely no final cause or purpose. Rather, I think that meaning is an emergent property; it appeared on Earth when the brains of our ancestors became large enough to allow for primitive culture – probably between 3 and 4 million years ago with the emergence of Australopithecus in the Rift Valley. There are surely other intelligent beings in the billions of galaxies beyond the Milky Way, and if the modern theory of eternal inflation is correct, then there is an infinite number of inhabited worlds in the multiverse beyond the horizon. I am much less certain that there are large numbers of civilisations sharing our galaxy, however, which is why I use the term ‘isolated’. If we are currently alone in the Milky Way, then the vast distances between the galaxies probably mean that we will never get to discuss our situation with anyone else.

      We will encounter all these ideas and arguments later in this book, and I will carefully separate my opinion from that of science – or rather what we know with a level of certainty. But it is worth noting that the modern picture of a vast and possibly infinite cosmos, populated with uncountable worlds, has a long and violent history, and the often visceral reaction to the physical demotion of humanity lays bare deeply held prejudices and comfortable assumptions that sit, perhaps, at the core of our being. It seems appropriate, therefore, to begin this tour of the human universe with a controversial figure whose life and death resonates with many of these intellectual and emotional challenges.

      Giordano Bruno is as famous for his death as for his life and work. On 17 February 1600, his tongue pinioned to prevent him from repeating his heresy (which recalls the stoning scene in Monty Python’s Life of Brian when the admonishment ‘you’re only making it worse for yourself’ is correctly observed to be an empty threat), Bruno was burned at the stake in the Campo de’ Fiori in Rome and his ashes thrown into the Tiber. His crimes were numerous and included heretical ideas such as denying the divinity of Jesus. It is also the opinion of many historians that Bruno was irritating, argumentative and, not to put too fine a point on it, an all-round pain in the arse, so many powerful people were simply glad to see the back of him. But it is also true that Bruno embraced and promoted a wonderful idea that raises important and challenging questions. Bruno believed that the universe is infinite and filled with an infinite number of habitable worlds. He also believed that although each world exists for a brief moment when compared to the life of the universe, space itself is neither created nor destroyed; the universe is eternal.

      Although the precise reasons for Bruno’s death sentence are still debated amongst historians, the idea of an infinite and eternal universe seems to have been central to his fate, because it clearly raises questions about the role of a creator. Bruno knew this, of course, which is why his return to Italy in 1591 after a safe, successful existence in the more tolerant atmosphere of northern Europe remains a mystery. During the 1580s Bruno enjoyed the patronage of both King Henry III of France and Queen Elizabeth I of England, loudly promoting the Copernican ideal of a Sun-centred solar system. Whilst it’s often assumed that the very idea of removing the Earth from the centre of the solar system was enough to elicit a violent response from the Church, Copernicanism itself was not considered heretical in 1600, and the infamous tussles with Galileo lay 30 years in the future. Rather, it was Bruno’s philosophical idea of an eternal universe, requiring no point of creation, which unsettled the Church authorities, and perhaps paved the way for their later battles with astronomy and science. As we shall see, the idea of a universe that existed before the Big Bang is now central to modern cosmology and falls very much within the realm of observational and theoretical science. In my view this presents as great a challenge to modern-day theologians as it did in Bruno’s time, so it’s perhaps no wonder that he was dispensed with.

      Bruno, then, was a complex figure, and his contributions to science are questionable. He was more belligerent free-thinker than proto-scientist, and whilst there is no shame in that, the intellectual origins of our ascent into insignificance lie elsewhere. Bruno was a brash, if portentous, messenger who would likely not have reached his heretical conclusions about an infinite and eternal universe without the work of Nicolaus Copernicus, grounded in what can now clearly be recognised as one of the earliest examples of modern science, and published over half a century before Bruno’s cinematic demise.

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      Nicolaus Copernicus was born in the Polish city of Torun in 1473 and benefited from a superb education after being enrolled at the University of Cracow at 18 by his influential uncle, the Bishop of Warmia. In 1496, intending to follow in the footsteps of his uncle, Copernicus moved to Bologna to study canon law, where he lodged with an astronomy professor, Domenica Maria de Novara, who had a reputation for questioning the classical works of the ancient Greeks and in particular their widely accepted cosmology.

      The classical view of the universe was based on Aristotle’s not unreasonable assertion that the Earth is at the centre of all things, and that everything СКАЧАТЬ