The Universe Within (4 page)

Newton's law of gravity describes with exquisite precision the invisible, inexorable tie that binds the seat of your pants to your chair, holds the Earth and the planets in orbit around the sun, holds the stars in their spherical shape and keeps them in their galaxies. At the same time, it explains how Earth's gravity affects everything from baseballs to satellites. That exactly the same laws should apply in the
un
earthly and hitherto divine realm of the stars as in the imperfect human world around us was a conceptual and indeed a spiritual break with the past. As Stephen Hawking has said, Newton unified the heavens and the Earth.

Newton's laws are as useful as ever. They are still the first rules that every engineer learns. They govern how vehicles move, on Earth or in space. They allow us to build everything from machines and bridges to planes and pipelines — not just by crafting, eyeballing, and adjusting, but by design. Although Newton discovered his laws by thinking about the motion of planets, they enabled the development of a vast number of technologies here on Earth, from bridge building to the steam engine. His notion of force was the key to all of it. It explained how we, through controlling and governing forces, could harness nature to our purposes.

More than three centuries after he published his findings in
Mathematical Principles of Natural Philosophy
,
known as the
Principia
, Newton's universal laws of motion and gravitation are still the foundation for much of engineering and architecture. His discoveries underpinned the Industrial Revolution that transformed the organization of human society.

The universe that Newton's laws describe is sometimes called the “classical” or “clockwork” universe. If you know the exact position and velocity of every object at one time, then in principle Newton's laws predict exactly where every object was or will be at any time in the past or future, no matter how remote. This classical universe is completely deterministic, and it is straightforward and intuitive. But as we shall see, in this respect it is utterly misleading. Before we get to that part of the story, we must discuss another outsider who, two hundred years later, would make a discovery even greater than Newton's.

· · ·

THE STORY OF THE
discovery of the nature of light begins, appropriately enough, with the great flowering of intellectual thought known as the Scottish Enlightenment. At the turn of the eighteenth century, after a dark and brutal period of domination by the monarchy and the Catholic Church, England was preoccupied with building the British Empire in Africa, the Americas, and Asia, giving Scotland the space to establish a unique identity. Scotland emerged with a powerful national spirit, determined to set its own course and to create a model society. Scotland's parliament founded a unique public school system with five hundred schools, which, by the end of the eighteenth century, had made their country more literate and numerate than any other in the world. Four universities were founded — in Glasgow, St. Andrews, Edinburgh, and Aberdeen — and they were far more affordable than Oxford or Cambridge, the only universities in England. The Scottish universities became centres of public education as well as academic study.

Edinburgh became the leading literary centre in Europe and home to luminaries such as David Hume and the political philosopher Adam Smith. According to Arthur Herman, author of
How the Scots Invented the Modern World
,
it “was a place where all ideas were created equal, where brains rather than social rank took pride of place, and where serious issues could be debated . . . Edinburgh was like a giant think tank or artists' colony, except that unlike most modern think tanks, this one was not cut off from everyday life. It was in the thick of it.”
21

Scottish academia likewise followed a distinct course, emphasizing foundational principles and encouraging students to think for themselves, explore, and invent. There was a lively debate, for example, over the meaning of basic concepts in
algebra
and geometry, and their relation to the real world.
22

This focus on the fundamentals was remarkably fruitful. As just one instance, English mathematician and Presbyterian minister Reverend Thomas Bayes, whose famous “Bayes theorem” was forgotten for two hundred years but now forms the basis for much of modern data analysis, attended Edinburgh University at the same time as Hume. Fast on the heels of Scotland's academic flowering came the great Scottish engineers, such as James Watt, inventor of the steam engine, and Robert Stevenson, who built the Bell Rock Lighthouse, off the coast of Angus, Scotland.

As the Western world entered the nineteenth century, the Industrial Revolution permeated and remade every aspect of life. The power of steam engines revolutionized the economy. Distances shrank with trains, steamships, and other conveyances; people moved en masse into cities to work in factories that made everything from textiles to pots and pans and that in so doing redefined notions of both work and economic value. A new breed of “natural philosophers” — mainly gentleman hobbyists — set out to understand the world in ways that had never before been possible. The effect of the Scottish Enlightenment was felt at the highest levels of science. Having spawned philosophers, writers, engineers, and inventors, Scotland now produced great mathematicians and physicists. One particular young genius would expose nature's inner workings to a degree that outshone even Newton.

Newton's physics explains a great many things, from the ebb and flow of the tides, caused by the moon's gravitational attraction, to the orbits of planets, the flow of fluids, the trajectories of cannonballs, and the stability of bridges — everything involving motion, forces, and gravity. However, Newtonian physics could never predict or explain the transmission or reception of radio waves, the telephone, electricity, motors, dynamos, or light bulbs. The understanding of all this, and a great deal more, we owe to the experimental work of Michael Faraday, born in 1791, and its theoretical elaboration by James Clerk Maxwell, born four decades later.

One can see the pair, Faraday and Maxwell, as the experimental yin and the theoretical yang of physics. Together, they typify the golden age of Victorian science. The well-born, well-educated Maxwell (he was heir to a small Scottish estate) fits a definite type: a gentleman scientist who, largely freed from the pressures of earning a living, pursued science as an ardent, passionate hobbyist.

James Clerk Maxwell was a bright and curious child, born in southern Scotland. Having the run of his family's estate in Glenlair
(click to see photo)
, he was interested in everything natural and man-made. “What's the go o' that?” he asked, again and again, picking up insects or plants or following the course of a stream or a bell-wire in the house. Joining a private school — the Edinburgh Academy — at age ten, he was known as “Dafty” and bullied, in part for his strange clothes, designed by his father who, though a lawyer by profession, was scientifically minded. By fourteen, with his father's encouragement, Maxwell had become a keen mathematician, preparing a paper describing a new way to draw ovals, which was read to the Royal Society of Edinburgh by a local professor.

The Scottish educational system was particularly strong in mathematics. Rather than learning mathematics by rote as what one professor contemptuously termed a “mechanical knack,” students worked through the fundamentals from first principles and axioms. When James Clerk Maxwell found his first great friend, Peter Guthrie Tait, as a schoolkid, they amused themselves by trading “props,” or “propositions” — questions they'd make up to try to outwit one another. It became their bond, and decades later, when they were both eminent physicists, Maxwell continued to send his old friend questions that stumped him and whose answers helped him piece together the puzzle of electromagnetism.

Maxwell, Tait, and William Thomson — later Lord Kelvin — who was educated at Glasgow University, formed a Scottish triumvirate, with all three becoming leading physicists of their time. Tait and Thomson co-authored the
Treatise on Natural Philosophy,
the most important physics textbook of the nineteenth century. Tait founded the mathematical theory of knots and Lord Kelvin made major contributions to many fields, including the theory of heat, where his name is now attached to the absolute scale of temperature. Alexander Graham Bell, another great Scottish inventor, followed Maxwell to university in Edinburgh before emigrating to Canada and developing the telephone.

After three years at Edinburgh University, Maxwell moved to Cambridge. One of his professors at Edinburgh commented in his recommendation letter, “He is not a little uncouth in manners, but withal one of the most original young men I have ever met with and with an extraordinary aptitude for physical enquiries.”
23
Whereas the education at Edinburgh had been free-thinking and broad, Cambridge was far more competitive and intense, and much of his time was spent cramming for exams. After coming second in the university in his final exams, Maxwell was appointed as a Trinity College Fellow at the age of twenty-three. This gave him time to investigate a variety of phenomena, from fish-eye lenses to the flight of falling pieces of paper, and even the ability of cats to right themselves if dropped. He also demonstrated, using coloured spinning tops, that white light is a mixture of red, green, and blue.

Just a year later, in 1856, Maxwell moved to Aberdeen
to take up a chair of natural philosophy. He spent five years there before moving to King's College, London. During this period he contributed to many different fields, applying in each case a deft combination of physical insight and mathematical skill. He showed that Saturn's rings were composed of particles, a theory confirmed by the
Voyager
flybys of the 1980s. He developed models of elasticity and discovered relations in the
theory
of heat, both of which are still used by engineers. Later on in his career, he worked out the statistical properties of molecules in a gas and he demonstrated the first-ever colour slide. But the feat that unquestionably trumps them all began in 1854, when he tried to clean up a bunch of messy equations having to do with electricity and magnetism.
24

Michael Faraday, by contrast, was the son of a South London blacksmith and left school at thirteen to become a bookbinder's apprentice. He had no formal scientific education and no mathematics, but he had a deep curiosity about the world, an alertness to it, and marvellous physical intuition.

On reading an article on electricity in an encyclopedia he was binding, Faraday was captivated. One of the bookbinder's customers, perceiving the lad's evident intelligence and thirst for knowledge, gave him tickets to lectures by Sir Humphrey Davy, one of the great scientists of the day, at the Royal Institution. Having attended the lectures, Faraday copied out his copious notes, which amounted to a virtual transcription of the lectures, and presented them, beautifully bound, to the great man. This led to a job, first as a bottle washer in Davy's lab and, soon enough, as his right-hand man. Eventually he succeeded Davy as the director of the Royal Institution. Despite its walls of inequity and injustice, the Victorian age sometimes let in chinks of light, such as its workingmen's colleges and public lectures bringing science to the general populace.

As a mature scientist, Faraday was indefatigable and responsible for a staggering range of discoveries. But what fascinated him above all was electricity and magnetism, and he was by no means alone in this. Although electricity had been observed for millennia in certain shocking fish and in lightning, by the nineteenth century its magical properties were beginning to be widely appreciated, though they were not understood. Its spark and sizzle were lifelike — it galvanized the age, you might say. Mary Shelley's
Frankenstein; or, The Modern Prometheus
was inspired by electrical experiments, often carried out in public, on living and dead creatures in early nineteenth-century London. Its title compared the modern scientist to the ancient Greek hero Prometheus, a lesser god who became a champion of mankind. He stole fire from the king of the gods, Zeus, and gave it to man. Shelley's book was a cautionary tale: for his crime, Prometheus was condemned by Zeus to be chained to a rock and have his liver eaten out by an eagle every day, only for it to grow back every night.

Faraday came to know electricity better than anyone, and his work was far ahead of its time. He showed that chemical bonds are electrical, discovering the laws of electrolysis and electrical deposition of one metal onto another. Faraday had a genius for discovering new phenomena using simple experiments. He investigated the magnetic properties of bismuth, iodine, plaster of Paris, even blood and liver. He blew soap bubbles filled with various gases — oxygen, nitrogen, hydrogen — through a magnetized region. He found that an oxygen-filled bubble got stuck in the magnetized region because oxygen is paramagnetic. (The explanation had to wait another ninety years, for the invention of quantum mechanics.)

Faraday also demonstrated the process of electromagnetic induction: how you can seemingly pull electricity out of a magnet by moving a wire past it. Faraday employed this in his invention of dynamos and transformers, now used to generate and distribute electricity all over the
world. He even discovered superionic conduction, the
basic mechanism of modern fuel cells.
25

Faraday also showed that when a metal container is electrically charged, the charge moves onto the outer surface. He sat in a square cage, twelve feet on a side, while his assistant charged it to 150,000 volts. Sparks flew wildly everywhere. His hair flared out in a halo, but he was unharmed — the charge was all on the outside. The next time you fly through a lightning storm in a plane, thank Michael Faraday for showing that it would be safe!