The Little Book of Big History

The Story of Life, the Universe and Everything

Ian Crofton, Jeremy Black

• Publisher: Michael O'Mara
• Year: 2016
• Print ISBN: 9781782436850
• eBook ISBN: 9781782434306
• Topic: History
• Subtopic: World History
• Index: History

From the Big Bang to the future of our planet, The Little Book of Big History divides history into manageable but comprehensive time frames, encompassing the cosmos, the stars, life and everything in between. Big History is the attempt to understand and condense the entire story of the cosmos, from the Big Bang to the current day. Combining methods from history, astronomy, physics and biology to draw together the big story arcs of how the universe was created, why planets formed and how life developed, this creates a unique perspective from which to understand the place of mankind in the universe. Excited by the alternative 'framework for all knowledge' that is offered by this approach, Bill Gates is funding the Big History Project, which aims to bring the subject to a wider audience around the world.The Little Book of Big History breaks down the main themes of Big History into highly informative and accessible parts for all readers to enjoy. By giving a truly complete timeline of world events, this book shines a whole different light on history as we learned it and makes us think of our history – and our future – in a very different way.

PART ONE

SETTING THE SCENE

How did we get to where we are now? The back story to the chronicle of humanity is a long one. There would be no human history without a physical place for it to unfold. So to truly understand ourselves, we have to understand how the universe came into being, how the stars and planets formed, why our planet has the right conditions for life to have appeared. And we also need to understand how living things work, and how they evolved, and how we have ended up – with us.

TIMELINE

13.8 billion years ago: The Big Bang brings the universe into existence.

4.6 billion years ago: Formation of our solar system, including the Sun, the Earth and the other planets.

4.5 billion years ago: The Moon is formed, probably as a result of a collision between the Earth and a Mars-sized planet.

4.2 billion years ago: Oceans may have begun to form.

4.1–3.8 billion years ago: Earth and other inner planets suffer numerous impacts from asteroids.

4 billion years ago: Formation of oldest rocks still present on the Earth. Possible appearance in the oceans of self-replicating molecules, such as DNA.

3.7 billion years ago: Earliest indirect evidence of life on Earth suggests bacteria-like organisms feeding on organic molecules.

3.4 billion years ago: Cyanobacteria (blue-green algae) emerge, which draw energy from photosynthesis.

2.45 billion years ago: Start of the build-up of free oxygen in Earth’s atmosphere, as a by-product of photosynthesis.

IN THE BEGINNING

Before the advent of modern science, there was a range of beliefs about the age of the Earth, and of the universe. Some Christians believed that God created both a mere 6,000 years ago. Ancient Hindu texts, in contrast, talk of an infinite cycle of creation and destruction.

Towards the end of the 18th century, geologists began to realize that the Earth must be much more ancient than had been thought (at least in Europe) – perhaps millions if not billions of years old. However, into the 20th century the scientific consensus was that the universe itself was eternal, and in a ‘steady state’. Stars might be born and die, but the dimensions of the universe were fixed and unchanging.

A chink in this theory came in the 1920s when the American astronomer Edwin Hubble observed that the further away a galaxy is from us, the faster it is receding. He concluded that the universe is expanding, and that this expansion started in a single great explosion, which became known as ‘the Big Bang’.

Arguments persisted between the proponents of the steady state and those of the Big Bang. Then in 1964 two radio astronomers working in New Jersey, Arno Penzias and Robert Wilson, noticed that their sensitive microwave receiver was suffering from constant interference, the same in all directions, with a wavelength representing a temperature of 2.7 degrees above absolute zero. At first they thought the phenomenon might be caused by the proximity of New York City or by pigeons defecating on their instrument. Eventually they realized that what their receiver was picking up was an echo of the Big Bang. If you retune your radio, part of the ‘white noise’ you hear between stations is this very same echo from the beginning of time.

The Big Bang

Cosmologists have now come up with a timetable that positions the Big Bang about 13.8 billion years ago, at a single point, a singularity, whose density and temperature were infinite. Once expansion started, it came at unimaginable speed. Between 10^-36 and 10^-32 seconds, the volume of the universe expanded by a factor of at least 10⁷⁸.¹ At this stage the only matter was elementary particles such as quarks and gluons. At about 10^-6 seconds, as expansion slowed down and temperatures fell, quarks and gluons came together to form protons and neutrons. A few minutes later the temperature had cooled further, to about 1 billion degrees, and protons and neutrons combined to form the nuclei of deuterium and helium, though most protons remained unattached as hydrogen nuclei. Eventually, the positively charged nuclei attracted negatively charged electrons to create the first atoms. These simple atoms were to become the building blocks of the stars.

‘Why does the universe go to all the bother of existing?’

Stephen Hawking, A Brief History of Time (1988)

THE BIRTH AND DEATH OF STARS

As the early universe expanded, matter was evenly distributed through space. But as tiny irregularities in density began to appear, gravity began to play a role, with denser regions attracting more and more matter. In this way clouds of gas, largely comprising hydrogen and helium, were formed. These so-called nebulae were where stars were – and continue to be – born.

Within a nebula, denser areas may begin to collapse in on themselves because of gravity, and these areas may eventually become dense and hot enough for nuclear fusion to begin – a reaction in which hydrogen is converted to helium, producing vast amounts of heat and light. It is this process that causes the stars – including the Sun – to shine with such intense brightness.

Just as gravity pulls together denser areas of gas to form stars, so it gathers stars to form galaxies. Our galaxy, the Milky Way, contains 100–400 billion stars and has a diameter of around 100,000 light years – meaning that light travelling at a speed of 300,000 kilometres per second takes 100,000 years to pass across it. Our Sun lies on one of the spiral arms of our galaxy, about 30,000 light years from the centre. The nearest star to the Sun is Proxima Centauri, just 4.24 light years away. The Milky Way is one of at least 100 billion galaxies in the universe. The size of the universe is a subject of speculation, but the part of it we can observe is 93 billion light years in diameter.

‘The wonder is, not that the field of the stars is so vast, but that man has measured it.’

Anatole France, The Garden of Epicurus (1894)

Different sizes of stars may undergo particular sequences in their lifetimes. Those similar in size to the Sun burn at something like 6,000 degrees on the surface (the core is much hotter) for at least 10 billion years before they exhaust their hydrogen. At this stage, the core contracts and the temperature rises to 100 million degrees, allowing helium fusion to begin. The star expands to become a red giant, around 100 times larger than in its youth, before shrinking to become a white dwarf, 100 times smaller than the original.

Larger stars have shorter lives. For example, a star ten times the size of the Sun will turn into a red giant after only 20 million years. As the temperature increases, the star begins to synthesize heavier and heavier elements, until at 700 million degrees iron is created. This process is the origin of many of the elements that make up planets such as the Earth – not only iron, but also carbon, oxygen and silicon. At this point the star blows apart in a massive explosion called a supernova, a fast-expanding cloud of gas and dust. At its centre is an object called a neutron star, only 10 to 20 kilometres in diameter, but so dense that a cubic centimetre of its material has a mass of 250 million tonnes. Even larger stars may end their lives as a black hole, an area of space so dense that not even light can escape its immense gravitational pull. There may be a supermassive black hole at the centre of our own galaxy.

THE GOLDILOCKS ZONE

The solar system – the Sun and its planets – formed about 4.6 billion years ago from a nebula – a spinning cloud of dust and gas. As denser patches of dust attracted more and more material by force of gravity, so the planets were formed. They all still spin in the same direction.

Earth is less than one-tenth of the size of the Sun’s largest planet, Jupiter, and Jupiter only one-tenth the size of the Sun. The Earth is 149,600,000 km from the Sun, Jupiter is five times further out, and the outermost major planet, Neptune, thirty times further. The relatively small inner planets – Mercury, Venus, Earth and Mars – are rocky in composition, whereas the giant outer planets – Jupiter, Saturn, Uranus and Neptune – mostly consist of gas surrounding a small rocky core.

Life as we know it is based on the cell, and for cells to function water must exist in a liquid state. Both Mercury and Venus are too close to the Sun for this to happen. It is possible that the conditions for life might once have existed on Mars, and NASA’s rovers on the surface of the planet are exploring this possibility. The outer planets are much too cold to support life, although liquid water may exist under the surface of some of their moons.

As far as we know, though, Earth is the only planet in the solar system that houses life. Earth is said to lie in the ‘Goldilocks zone’, the region around a star where the conditions are just right for life. In the tale of Goldilocks and the Three Bears, Goldilocks picks the porridge that is neither too hot nor too cold, the chair that is neither too small nor too big, and the bed that is neither too hard nor too soft. Earth is neither too close nor too far away from the Sun (and thus not too hot nor too cold) for water to exist as a liquid. It is large enough to generate a strong gravitational field to hold on to an atmosphere, and thus has sufficient atmospheric pressure to allow liquid water to exist on the surface.

Are we alone in the universe?

Recent detailed observations of our own galaxy suggest that it may contain as many as eleven billion Earth-size planets orbiting Sun-like stars within the Goldilocks zone. It is thought that the nearest such planet is twelve light years away, meaning that it would take twelve years for a radio signal from Earth to reach it. But having these minimal conditions does not necessarily mean that a planet does possess life – let alone a form that has evolved enough to send us a radio signal. Indeed, although radio telescopes around the world have been monitoring the airwaves for decades, no signs of intelligent extraterrestrial life have been detected.

THE RESTLESS EARTH

Our planet is a not-quite-regular sphere, layered like an onion. In the centre, its inner core consists of solid iron. Around this lies first the outer core, of molten iron, and then the mantle, made up of molten rock called magma. Floating on top of the mantle is a thin crust made of solid rock. We live on the surface of the crust. Although humans have been to the Moon, no one has gone deeper below the surface than 4 km, the depth of the deepest mine.

The Earth has one more layer, a gaseous skin. This is the atmosphere, more than three-quarters of which is nitrogen and one-fifth oxygen, essential to most forms of life. There are small amounts of other gases, but of these carbon dioxide and methane – the so-called greenhouse gases – have a crucial bearing on life on Earth (see here), as does the presence of water vapour, an essential component in all weather systems. The density of the atmosphere grows thinner with altitude and gradually fades into space.

Just as the gases in the atmosphere are constantly in motion, so too are the rocky plates that make up the crust. Scientists used to assume that the continents and seas had always been in the same positions. Then in 1915 a German meteorologist called Alfred Wegener suggested that rather than being static, the continents had...

Table of contents

• Cover
• Title page
• Copyright page
• Contents
• PART ONE: SETTING THE SCENE
• TIMELINE
• In the beginning
• The birth and death of stars
• The Goldilocks zone
• The restless Earth
• Shaping the surface
• What is life?
• Where does the energy come from?
• Life gets complicated
• How life carries on
• The origin of species
• The blueprint of life
• PART TWO: ANIMAL PLANET
• TIMELINE
• The first animals
• Life comes ashore
• The age of the dinosaurs
• Mass extinctions
• The coming of the mammals
• Where do we come from?
• PART THREE: HUMANS START TO DOMINATE
• TIMELINE
• Humans past and present
• What makes humans human?
• Culture
• How humans populated the world
• The impact of the ice
• From scavenger to hunter
• Fire
• Hunter-gatherer technologies
• Language
• Kinship
• Early religion
• The beginning of art
• Shelter
• Clothing
• Pottery
• The first farmers
• Domesticating animals
• Putting animals to work
• The wheel
• Nomads
• From stone to bronze
• From bronze to iron
• PART FOUR: CIVILIZATION
• TIMELINE
• Early trade routes
• The birth of cities
• Transport
• From barter to money
• Paper money
• Credit, debt and investment
• Writing
• Law
• Ancient empires
• Why empires fall
• Polytheism and monotheism
• Epics
• Writing history
• The nature of reality
• What is the good life?
• The beginnings of science
• Disease pandemics
• Europe in transition
• Land, labour and power
• Clashes of civilizations
• PART FIVE: THE RISE OF THE WEST
• TIMELINE
• Renaissance and Reformation
• The long road to toleration
• Printing
• The Scientific Revolution
• Europe expands
• The Enlightenment
• The Industrial Revolution
• The Agricultural Revolution
• The social contract
• From mercantilism to free-market capitalism
• Nationalism and the nation
• Urbanization
• Expanding horizons
• The peak of imperialism
• Trade unions, socialism and communism
• PART SIX: THE MODERN WORLD
• TIMELINE
• Modernism in the arts
• Towards gender equality
• Revolutions in science
• Fighting disease
• The road to world war
• Industrialized slaughter
• Versailles and its outcomes
• Revolutions
• World economic collapse
• Totalitarianism
• Total war
• Genocide
• The nuclear age
• The Cold War
• Life after the Cold War
• The information revolution
• The promises of bioscience
• Internationalism, globalization and the future of the nation-state
• Population
• Migration
• Economic developments
• Environmental problems
• The future of humanity
• The fate of the universe
• Picture acknowledgements
• Index