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- Herausgeber: Icon Books
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
- Veröffentlichungsjahr: 2021
The breakthroughs that have had the most transformative practical impacts, from thermodynamics to the Internet. Physics informs our understanding of how the world works – but more than that, key breakthroughs in physics have transformed everyday life. We journey back to ten separate days in history to understand how particular breakthroughs were achieved, meet the individuals responsible and see how each breakthrough has influenced our lives. It is a unique selection. Focusing on practical impact means there is no room for Stephen Hawking's work on black holes, or the discovery of the Higgs boson. Instead we have the relatively little-known Rudolf Clausius (thermodynamics) and Heike Kamerlingh Onnes (superconductivity), while Albert Einstein is included not for his theories of relativity but for the short paper that gave us E=mc2 (nuclear fission). Later chapters feature transistors, LEDs and the Internet.
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For Gillian, Chelsea and Rebecca
Contents
Introduction
Physics is central to our understanding of how the world works. But more than that, key breakthroughs in physics – and physics-based engineering – have transformed the world we live in. In this book, we will journey back to ten key days in history to understand how a particular breakthrough was achieved, meet the individuals responsible and see how that breakthrough has influenced our lives.
It is fashionable for historians of science to criticise the idea that individuals deserve to be considered geniuses who have made a unique contribution. And, as will be made clear, it is certainly true that all of the people picked out on our ten days built their contributions on the work of others. Yet there is no doubt that until the three most recent of our days, each individual was responsible for a change that contributed to making the modern world possible.
In 21st-century physics, significant breakthroughs are often the work of big teams. The research undertaken at the CERN particle laboratory or on the LIGO gravitational wave experiment in the US can involve hundreds or even thousands of contributors. Yet historically there have been individuals whose contributions have been more than that of a standard cog in a wheel. These are people who stand out beyond their peers, however much their work may have depended on the wider canvas of thinkers of their day. And even now, although many scientists may work on a particular theory or xii experiment, there is often a key moment when a handful of individuals have been pivotal in making a discovery happen.
The earlier days in our journey through the history of physics involve the development of a fundamental understanding of the underlying science, while the later ones highlight physics-based engineering, involving the invention of new ways to use physics knowledge. It’s not that we haven’t seen new developments in pure physics that have changed our understanding of the universe since the 1950s, but most of the more recent such advances have had fewer direct impacts on our lives. Black holes or the Higgs boson, for example, are fascinating, but lack practical applications. In this book, we stay with physics and its applications that made the modern world.
We will begin back in 1687 with the publication of Isaac Newton’s remarkable book Philosophiae Naturalis Principia Mathematica. Now virtually unreadable without professional guidance, as much for its style as for being in Latin, the publication of the Principia nonetheless represented a major move forward in the power of natural science. At the time, under a different type of curriculum to the present day, what Newton did was regarded as mathematics rather than physics. Even so, this was a pivotal moment in the history of science.
For our second day, we travel forward to 1831, shortly before the Victorian period, for Michael Faraday’s paper on electrical induction. Recently, some of those attempting to inflate the importance of artificial intelligence have claimed that AI is ‘more important than electricity’. Leaving aside the absurdity that it is impossible to have artificial intelligence without electricity, this overlooks the reality that electricity is absolutely central to modern life – and becoming even more so as we move away from fossil fuels to electricity to power, xiii for example, cars, heating and industrial energy. Faraday’s work kickstarted the practical use of what had been up to that point an entertaining novelty without worthwhile application.
We wholeheartedly enter the Victorian era on Day 3 in 1850, moving forward a couple of decades from Faraday to meet the less familiar Rudolf Clausius and explore his contribution to thermodynamics. It was thermodynamics that took the industrial revolution to a whole new level, with a better understanding of the steam engine. Equally, thermodynamics would make possible other heat engines, from the internal combustion engine to the turbines in power stations, and now underpins the mechanisms of modern heating, fridges and air conditioning. We may be losing our dependence on internal combustion, but the others remain important and thermodynamics is, at its most basic, the driving force behind life itself.
Just over ten years later, in 1861, Day 4 introduces us to Scottish physicist James Clerk Maxwell. Where Faraday gave us the means to make use of electricity, Maxwell’s work opened up an understanding of the electromagnetic spectrum that includes visible light, but gives us far more. Not only did this lead to radio, microwaves, TVs and X‑rays, Maxwell’s legacy is typified by that wildly successful piece of technology, the mobile phone, with over 3 billion deployed worldwide.
Day 5 takes us to the final years of the 19th century and the work of the phenomenon that was Marie Curie. A woman who thrived in what was then firmly a man’s world, Curie achieved remarkable things in the study of radioactivity, and the use of X‑rays, with major medical benefits. On this key day, Curie revealed her most important discovery in the science of radioactive materials, radium, and set the direction for the study of radioactivity that seemed able to produce energy from nowhere.
xiv The explanation for the source of radioactive energy came on Day 6 in 1905, with the publication of the last of a series of papers in that year that took Albert Einstein from being an obscure patent clerk to a name that would be celebrated across the world. In just three pages, Einstein showed how the special theory of relativity (published just a few months earlier) forged an unbreakable link between mass and energy, leading to the most famous equation of all time, E=mc2.
For Day 7, we discover an unfamiliar name to many in the Dutch physicist Heike Kamerlingh Onnes. Working in the early years of the 20th century, Kamerlingh Onnes was the master of ultra-low temperatures and discovered superconductivity, where electrical resistance disappears, making it possible to produce the super-strong magnets required for levitating trains, MRI scanners and specialist applications such as particle accelerators.
Superconductivity is a quantum effect, and Day 8 finds us in 1947, with the viewpoint shifting from basic physics to applications of quantum theory – in particular the then rapidly developing field of electronics. It was on this day that John Bardeen and Walter Brattain, based at Bell Labs, made the earliest working transistor, the first generation of a device that would transform all our lives.
Quantum effects were also behind our Day 9 invention in 1962 of the light emitting diode (LED). This is a particularly hard event to pin down in history, as there were so many stages in the development of this technology, which is why it has only been in the 21st century, some 50 years after that date, that LEDs have become the dominant method of lighting our homes, streets and workplaces. The many subtle variants in early attempts make the choice of James R. Biard and Gary Pittman’s breakthrough one of several possible key days; however, the pair have one of the best claims after producing the first commercially viable LED. xv
The last of our historical days in physics, Day 10, sees the first link made in 1969 in the computer network that became the internet. As with LEDs, Steve Crocker and Vint Cerf were not the only ones involved in this project, but they played a crucial role, and are the most recognisable faces of the internet’s birth. It’s appropriate that this breakthrough took place the same year as the first human landing on the Moon, with Neil Armstrong’s famous ‘One small step for [a] man, one giant leap for mankind’. What was indeed a small step forward in connecting two large computers to enable remote access became what is arguably the giant leap of the definitive technology of the modern age.
Where do we go from here? In the final chapter, we look at a handful of different possibilities for a future Day 11. Whether it will be one of these or something completely different, we can say with some confidence that there is still plenty of opportunity for physics and physics-based technologies to once again enable a world-changing innovation. For now, though, it’s time to take a step back in time to a slower-paced age and Tuesday, 5 July 1687.
DAY 1
Tuesday, 5 July 1687
Isaac Newton – Publication of the Principia
When Newton’s crowning glory, the Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) – generally known as the Principia to make it less of a mouthful – was published, physics in the modern sense, making use of mathematics, was born. Featuring Newton’s three laws of motion and his law of gravitation, and developed using his new and essential mathematical tool of calculus, the Principia set in place the mechanical principles linking forces to movement that would enable the industrial revolution to flourish, established the laws that underpin the working of jet engines and aircraft wings, and supplied the gravitational calculations needed to give us the satellites that provide everything from weather forecasts to GPS.
What makes the publication of a book world-changing? It might be at the core of a world religion or a political movement. It could be read by many millions of people and change their lives. It could be responsible for a fundamental change to society. But Isaac Newton’s masterpiece fulfils none of these functions. Instead, it changed the understanding of the universe and how it works for a 2 relatively small audience, who then spread the benefits of that understanding to the rest of us.
Interestingly, the Principia has something in common with novels that regularly make the ‘greatest book of all time’ lists – books like Proust’s À la Recherche du Temps Perdu and James Joyce’s Ulysses. Like them, this is a book that is widely acknowledged as being brilliant, but that very few people in recent years have managed to read (even among those of us who have attempted to do so). Yet, without doubt, this wordy Latin tome, loaded with obscure geometry, has had far greater impact than any literary masterpiece.
The year 1687
A notably uneventful year. Beyond the handful of localised European wars typical of the period, 1687 is unusual in being totally dominated by a single scientific event: the publication of Newton’s Principia.
Newton in a nutshell
Isaac Newton
Physicist, mathematician, alchemist, heretical religious scholar, MP and bureaucrat
Legacy: Newtonian reflecting telescope, colour theory of light, laws of motion, law of universal gravitation, calculus (method of fluxions)
Born 25 December 1642 at Woolsthorpe Manor, Lincolnshire
Educated: Trinity College, Cambridge
Fellow of Trinity College, Cambridge, 1667–1696
Elected Fellow of the Royal Society, 1672
MP for Cambridge, 1689–1690 and 1701–1702
Warden of the Royal Mint, 1696–1699 3
Master of the Royal Mint, 1699–1725
President of the Royal Society, 1703–1727
Knighted by Queen Anne, 1705
Died 20 March 1727 at home in Kensington, London, England, aged 84
A new view of the universe
This is the story of a book that had a three-year genesis. Yet the history of the components that came together to make that book happen stretches back around 2,000 years. The first essential that led up to the production of the Principia was the developing understanding of the nature of moving objects and gravity. The second was the involvement of one remarkable man.
The physics of motion and gravitation that mostly held from ancient times through to the 17th century was built on two reasonably logical, yet incorrect beliefs. One was that an object had to be pushed if it was to be kept moving. This was apparent by observing most everyday objects. As soon as you stop pushing a cart it starts to slow down and soon it will come to a halt. An arrow that travels two hundred yards before hitting its target will arrive with noticeably less impact than one fired at point-blank range. There was, of course, one example of movement that did seem to carry on indefinitely – the motion of the planets and stars in the sky. But even this was thought to require pushing, usually as a result of divine intervention.
As far as gravity went, the accepted theory was tied into an impressively holistic picture of the universe that took in the nature of the physical elements. There were thought to be four elements that made up everything that existed below the orbit of the Moon: earth, water, air and fire. Two of these (earth and water) had a 4 natural tendency to head for the centre of the universe, the other two had a tendency to move away from the centre. This was not a case of having a force applied to them – a natural tendency was more like a dog’s natural tendency to dislike cats, an inherent part of its nature.
The tendency of earth and water towards the universal centre was described as gravity and the tendency of air and fire away from the centre was known as levity. This, incidentally, was a major underpinning of the Earth-centred view of the universe. The resistance to accepting the Sun-centred view is often portrayed as nothing more than religious obstinacy, but in fact having the Earth at the centre of everything underpinned the physics of the time, which predated Christianity and Islam. And it is anything but obvious that the heavens move because the Earth is rotating – it’s easy to be critical in hindsight, but we still talk of the Sun rising and setting as if the Earth were fixed in place.
The Ancient Greek physics that lay behind this thinking had started to be questioned in medieval times by both Arabic scholars and some of the European universities, though others remained staunch in their support of the familiar old models. However, by the mid-16th century, Copernicus had argued strongly for a Sun-centred universe. This simplified the old model, which had required the fiddly invocation of epicycles, spheres within spheres, to explain the odd movement of the planets in the sky as some reverse their apparent motion because of the interaction between their orbit and that of the Earth.
This approach had been famously supported by Galileo, whose unsubtle presentation of the Copernican view in a book that appeared to mock the Pope led to his trial. However, it should be emphasised that the Copernican model wasn’t the only game in 5 town. Adopting this system implied the need to rewrite all of physics. But in the late 16th century, the great Danish astronomer Tycho Brahe had proposed a system that did away with the problematic epicycles, but still kept the Earth at the centre of things.
In what’s known as the Tychonic model, the Sun, Moon and stars rotate around the Earth, but the other planets are centred on the Sun. In effect this is an accurate model of what really happens, given our viewpoint on the surface of the Earth. In the end it’s a matter of where we look from (frame of reference, as physicists call it) – and at the time, the only place we had was the surface of the Earth. If you take that viewpoint, Brahe was right. It all works, but does not require a change of the fundamentals of physics.
However, Galileo did more than argue for a Sun-centred universe. It’s odd in a way that we remember him for this, the work of Copernicus, and for inventing the telescope – which he didn’t do as there were several earlier telescope makers. Galileo’s great contribution was in reality a book he wrote after his trial while on house arrest. In Discorsi e Dimostrazioni Matematiche Intorno a Due Nuove Scienze (Discourses and Mathematical Demonstrations Relating to Two New Sciences) Galileo began to explore movement in the form of pendulums and balls rolled down slopes, performing experiments that ate away at the classical view of physics.
When Galileo rolled a ball down a slope, it accelerated. When he rolled it up a slope, it slowed down. It was reasonable to assume, with nothing else slowing it down, such as friction and air resistance, that a ball rolling on the flat would continue at the same speed. Just as the Copernican model required a move away from the old element-based view of gravity and levity, so this kind of exploration of the physics of motion undermined the classical idea that a push was required to keep things moving. 6
The Lincolnshire wonder
This was the scientific world – one where the old certainties were increasingly being questioned – into which Isaac Newton was born on 25 December 1642 in the Lincolnshire farmhouse known as Woolsthorpe Manor, into what could only reasonably be described as a troubled family.
Newton’s confusing dates
25 December 1642–20 March 1726 old style 4 January 1643–31 March 1727 new style
Isaac Newton has some of the most troublesome birth and death dates in the history of science. Even respectable biographical dictionaries have been known to get them wrong. The year he was born, the year he died, the well-known fact that he was born on Christmas Day and the idea that he was born the same year that Galileo died are all up for dispute, depending on the calendar that you use.
The problem arises from England’s late adoption of the Gregorian calendar, which did not take place until the 1750s. This means that when Newton was born, England was ten days behind the modern calendar, while by the time of his death, England was eleven days behind. To make things even more confusing, in the old calendar 25 March marked the start of the new year, distorting the date of Newton’s death. This odd date was based on the religious feast of the Annunciation, and is why in the UK the tax year still runs from 6 April one year to 5 April the next (which, allowing for the calendar shift, are the historical new year dates).
This confusion leads to downright errors where events on one calendar are linked to events on the other, such as the media’s tendency to note Newton’s birthday on the modern Christmas Day … but failing to note that the Christmas Day of the 17th century does not fall on 25 December in our calendar.
7 Newton’s upbringing was difficult. His father died before he was born and his mother, Hannah, remarried a local rector when Newton was three, abandoning the boy to her parents so she could live with her new husband’s family. We know that Newton suffered: in one of his notebooks, among his listed ‘transgressions’ were ‘Threatening my father and mother Smith to burn them and the house over them’ and ‘Wishing death and hoping it to some’.
Although Hannah came back to Woolsthorpe after her second husband’s death when Newton was eleven, the boy was soon parcelled off to school in Grantham, boarding with the family of Mr Clark, an apothecary in the town. Newton seems to have been initially disliked at school, but his practical skill at building mechanical models brought at least a degree of acceptance, even if he was never popular.
Trouble with Newton’s mother would continue, as she removed him from school to work on the farm. Newton regularly sought out opportunities to escape farm work and read; eventually, no doubt frustrated, his mother was persuaded to let him return to school when the headmaster excused Newton the 40-shilling fee usually charged to boys who came from outside the town. However, she would not support him when he went up to Cambridge, requiring him to take a position as a sizar where his keep was supported by acting as a servant to other students.
Cambridge and the Royal Society
Being a student at Cambridge required a profession of the Anglican faith in this period. We are used now to many scientists being atheists, but in Newton’s day, Christianity was an expected part of life in Britain and totally integrated into the thinking of European scientists. Newton was a devout Christian, but his beliefs started out 8 with a more puritanical flavour of Christianity than was common in the Church of England, and he would develop beliefs that were considered outright heresy by the standards of the day. It was also the norm that university fellows had to be single (this, at least, was not a problem for Newton) and ordained in the church – Newton obtained special dispensation from the King to avoid the latter requirement.
Over time, Newton’s beliefs strayed into Arianism. This was a doctrine originated by a 3rd-century Libyan priest named Arius, which rejected the conventional Christian concept of the Trinity and believed that Jesus was created by God, rather than existing from the beginning. Although there had been Arian churches historically, this was an unusual belief in Newton’s day, which he combined with an obsession with finding arcane meaning in ancient texts, culminating in the belief that the date of the end of the world would be no earlier than 2060, obscurely deduced from prophesies in the Bible books of Daniel and Revelation.
Newton’s non-conformist attitude to his religion was of a piece with the approach he took to science. At the time, the curriculum at Cambridge was primarily based on classical sources with little encouragement to question the wisdom of authority. Galileo’s books, for example, were too revolutionary to be found in the university’s libraries. But Newton’s approach echoed the motto of the Royal Society, which would become such a big part of his life: Nullius in verba (take no one’s word) – effectively, question everything. And there was plenty to question in a view of physics that had changed relatively little since the time of Aristotle. Newton wasn’t the first to challenge scientific authority – as we have seen, Galileo and others had done so – but he took the questioning to a new level. Newton was not a person who would go with the flow. Both in his experiments and 9 his increasing deployment of mathematics, he was prepared to go further, to stand out from the crowd.
Newton’s early scientific work was primarily on light. He was elected as a fellow of the Royal Society thanks to his construction of a reflecting telescope, but was soon at odds with the Society’s Curator of Experiments, Robert Hooke, who criticised Newton’s theories on colour. Hooke’s (mostly incorrect) negative remarks drove Newton to threaten to resign.
Of myths and personality
The battle with Hooke would develop into a lifelong feud. There seems little doubt that it was real. It seems likely, for example, that Newton was responsible for the destruction of Hooke’s portrait, leaving us without a contemporary image of a great scientist in his own right. Newton’s relationships with others were often prickly and, given the concerns of the day, sometimes difficult to be sure of in retrospect. This comes across most clearly in uncertainties about Newton’s sexuality.
This was a time when homosexual thoughts, let alone behaviour, would have been considered deeply sinful. Yet there is no evidence that Newton had any interest in the opposite sex. The only women other than his mother with whom he had any notable connection were Catherine Storer, the stepdaughter of the apothecary in Grantham, who claimed after Newton’s death that he had considered marrying her, and his half-niece Catherine Barton, who acted as his housekeeper towards the end of his life. By contrast, Newton certainly had a close relationship with John Wickins, with whom he shared accommodation for over twenty years.
Another relationship would develop with the much younger Swiss mathematician Nicolas Fatio de Duillier. For over five years 10 the pair exchanged affectionate letters and Newton not only gave the younger man gifts but gave voice to more feelings in his letters than he ever recorded elsewhere. If there was a relationship, it seems to have ended abruptly after a visit Newton made to Fatio in London in 1693 – this may have been because Newton felt Fatio was being indiscrete about their shared enthusiasm for alchemy, and almost certainly contributed to Newton’s imminent breakdown. For the next few months, Newton wrote to a number of his acquaintances telling them he wanted no more to do with them, even suggesting the philosopher John Locke had attempted to embroil Newton with women. He seems to have recovered quickly, but clearly this was a man under stress.
To modern eyes, the above-mentioned fascination with alchemy might also imply a troubled personality. Indeed, it was something of an obsession for Newton, dominating much of the period of his life when he made his achievements in physics. And it is possible that the materials he worked with, such as mercury, may have contributed to his breakdown. But the study of alchemy, though considered dubious (and if used in certain ways illegal) was not incompatible with the scientific thought of the day, and fits well with a mind that clearly straddled scientific and mystical religious thought.
A final example of the uncertainty around personal detail is in what is surely the most famous story concerning Newton: the apple. Despite some modern assertions to the contrary, Newton’s apple is not entirely mythical (though any idea of it landing on his head is). The source for the story of the apple is Newton himself, quoted by his younger contemporary, William Stukeley. In his book Memoirs of Sir Isaac Newton’s Life, Stukeley describes paying a visit to Newton in 1726 at Newton’s lodgings in Orbol’s Buildings in Kensington. Stukeley tells us that they were sitting under apple trees in the garden 11 after dinner (drinking tea) and Newton claimed that he had first thought about the nature of gravitation ‘occasion’d by the fall of an apple’.
Some suggest that this late revelation, when Newton was in his eighties, was an attempt to build up his own mythology at a time when Newton probably had no real recollection of the events: certainly, there is no earlier record of the apple incident. However, it is a perfectly reasonable assertion. To deny it seems more an attempt to be iconoclastic for the sake of it than a genuine concern for the truth. What certainly is true, though, is that Newton never had a strong urge to publish his work, often not making it public for many years. And this would be true of at least some of the contents of the Principia.
A reluctance to publish: the 1687 day
It has frequently been stated that Newton developed calculus and his theory of gravitation in a concentrated period of under two years from 1665 when dispatched home from Cambridge during an outbreak of plague. This is a wild exaggeration. He was certainly slow to publish his work on forces and gravitation, but when the Principia was eventually published it pulled together material he had been working on for over 20 years. Although Newton’s early work was sent to the Royal Society, after the criticism from Hooke, Newton refused to send in details of further theories on light, which he held back from the 1670s all the way through to the publication of his book Opticks in 1704. The factors that shaped Newton’s personality seem to have inclined him to secrecy. Although he was determined to be recognised as the first to come up with ideas, he resisted publication at every opportunity.
That the Principia was published at all was as much down to astronomer Edmund Halley as to Newton. Halley, Hooke and the 12 polymathic architect of St Paul’s Cathedral, Christopher Wren, had been talking about planetary motion in a London coffee house in 1684 when Hooke claimed to have proved that the force keeping the planets in their orbits decreased with the square of the distance between the planet and the Sun. Clearly suspecting more than a little boasting on Hooke’s part, the wealthier Wren offered a reward to Hooke if he could produce this proof in two months. When Hooke failed, Halley headed up to Cambridge to speak to Newton on the matter.
Newton also claimed to have performed the appropriate calculation showing such a force would produce elliptical planetary orbits, but couldn’t find where he had written it down. Three months later, he sent Halley nine pages on the topic, an undertaking that seems to have triggered the writing of the Principia. By the time the book was published in July 1687 it had become three volumes of Latin. The first, De Motu Corporum (On the Motion of Bodies) introduces basic concepts such as mass, gives us Newton’s three laws of motion, and provides calculations to support the elliptical, inverse square law motion of the planets.
The second volume, arguably the least significant, called – with a snappiness of titling later rivalled by Hollywood – De Motu Corporum Liber Secundus (On the Motion of Bodies, Book Two), adds resisting mediums such as air and considers pendulums, waves and vortices. And the third volume, De Mundi Systemate (On the System of the World), features Newton’s law of gravitation, describing a ‘universal’ force that is equally responsible for the fall of the famous apple as it is for the keeping the Moon in orbit around the Earth and the planets around the Sun.
As we have seen, and unlike his later book Opticks, which was written in English, the Principia was written in Latin. This had been the standard language of European academia in the early days 13 of universities, enabling scholars across Europe to move freely between universities and to share ideas. Academic books had been published in Latin for centuries. The use of Latin had indeed allowed an international readership, but it had also excluded the majority of the literate population from reading these books – something that was actively encouraged by many natural philosophers, who liked to quote remarks such as ‘It is stupid to offer lettuces to an ass, since he is content with his thistles’. There was a deliberate attempt in some quarters to keep the revelation of arcane matters from the common herd.
Title page of the Principia.
But this attitude was changing. Galileo, for example, wrote his key books in Italian, not in Latin. There was a parallel with the publication of the Bible in the modern languages of the day. One of the great moves of the Reformation of the 16th and 17th-century 14
