by Adam Frank
But not everyone was interested in time reform. As plans like Sanford’s one-world time became public, a growing chorus of protestors began vocally challenging any form of reworked hours. For those opposed to time reform, sun-bound time had to take precedence. As the superintendent of the U.S. Naval Observatory, John Rodgers, put it, “The Sun is the national clock. . . . No other clock can supersede it, as it is the one ordained by Nature to regulate man’s life.”12
The reformers came back with a hybrid system—a compromise between the economic needs of a nation stitched together by train lines and the natural local rhythms of day and night. They divided the nation up into time zones, each 15 degrees wide. The first, eastern zone began 75 degrees of longitude west of Greenwich, England (roughly the eastern edge of the East Coast). The second began 90 degrees of longitude west of Greenwich; the third time zone began at 105 degrees west, and the last 120 degrees west of Greenwich. Everyone 7½ degrees on either side of the meridian defining a zone’s centre would use the time defined on that central meridian.13
Once the major railways began to sign on to this plan, its opponents quickly saw they were outgunned. In fact, the protestors were outdistanced. When the final vote at the General Time Convention was held, the tally was taken in miles of railway track. Reform got 79,041 miles, with only 1,714 miles against the plan.14 The major railways had made their decision, forcing the major cities to fall in step. Understanding the need to tie their clocks to the economic lifelines of the railways, New York, Boston and Chicago agreed to give up their own local time standards and hitch their official rhythms to a centralized standard. Time had become nationalized by legislation.
FIGURE 5.2. The divisions of U.S. time before and after the 1883 Standard Time Convention.
Railways reshaped the human experience of time in more ways than simply providing short travel times between cities. The economic power inherent in the rapid transport of goods meant that oranges picked Monday in Florida could appear on the tables of middle-class families in New York a few days later.15 All the raw materials of the furiously expanding industrial economy were circulating along rail-driven arteries. A new, communal pace of human culture was emerging from the human engagement with steam, coal and steel. Wires would soon be added to that arsenal.
THE TELEGRAPH AND THE POLITICS OF SPACE-TIME
While every steam train was a massive reminder of the power of industry to reshape life, a more ephemeral transformation contributed to new institutional facts changing human time. From one end to the other, the planet was being strung together with telegraph cable. If railway lines formed a circulation system for the new world order of time, telegraph lines carrying precisely metered electrical signals represented its rapidly growing nervous system.
The click-click of the telegraph provided people with their first direct experience of simultaneity at great distances. In 1867 transatlantic cables were drawn from Greenwich to the Harvard Observatory in Cambridge, Massachusetts.16 Soon all the great cities of Europe and the United States were connected. A telegraph operator watching the electromechanical snaps of his receiver in Paris was tied to his fellow operator in New York tapping out the message. Time and space collapsed into the invisible domains of electric currents racing along wires lying on the ocean floor.
The consequences of establishing a common “now” for Paris and New York (or any other location linked by telegraph) would prove more far-reaching than the ability to send urgent news from one continent to another. Simultaneity in time translated into accuracy in space. It meant accurate maps. For the great land grab of late nineteenth-century empire building, mapmaking was a politically charged business.
The accurate measurement of global position had been an issue for centuries. As we saw in the last chapter, it was the determination of longitude—the east/west location from an agreed-upon meridian—that posed the problem. The accurate maritime clocks that John Harrison developed had gone a long way towards solving the problem, but carving empires out of Africa and the rest of the world demanded even greater precision. Determining if a rich copper deposit lay in a Belgian, Portuguese or British colony was more than an academic matter of cartography. Wealth and power would flow from exact maps.
Into this breach stepped the new technology of telegraphy, with accuracies that depended only on the engineering physics of tracking electric pulses through a very long wire. From the 1870s to 1900, the world powers went through a frenzy of cable laying. The Americans were wiring their western frontier. The French drew telegraph lines from the eastern shores of South America and draped them over the Andes.17 Far ahead of everyone, the British strung lines across the entire globe, stitching India to Indonesia and Jordan to Johannesburg. By 1880 the Earth was crisscrossed by ninety thousand miles (140,000 kilometres) of cable on the ocean floor alone. It was, in the words of Peter Galison,
a ninety-million-pound [forty-million-kilogram] machine binding every inhabited continent, cutting across to Japan, New Zealand, India, the West Indies, the East Indies, and the Aegean. Competing for colonies, for news, for shipping, for prestige, inevitably the major powers clashed over telegraphic networks. For through copper circuits flowed time, and through time the partition of the worldmap in an age of empires.18
With the new world-girdling network of telegraph cables, the message “It’s 12:02 in Greenwich” or “It’s 10:29 in Paris” could be (almost) instantaneously transmitted around the planet. Every node in the telegraph network could partake in simultaneity and share the same “now”. Recall that longitude is determined through a simultaneous comparison of local time with some standard (such as Greenwich time). With an accurate measure of simultaneity, equally exact calculations of longitude could be established. Errors in the difference between local time and Greenwich time shrank to tiny fractions of a second. Prefiguring our own era of geosynchronous GPS systems, the web of telegraph cables netted the Earth together. Every location, each inch of soil, could now in principle be tallied precisely on the great and growing electric world map. Terra incognita was shrinking into a few jungles and Arctic wastes as synchronized time was transformed into precise maps.
The emerging era of electrically co-ordinated time drew the first outlines of the coming global civilization. Human life and its uses for time were transforming so rapidly that a generation could no longer recognize the one that preceded it. In the wake of this rapid reordering of the human temporal order, cosmic time would once again have to be re-imagined.
At the very moment when the world was desperate to construct networks of electromagnetic simultaneity, the young Albert Einstein was hard at work for the Swiss Patent Office. His day job was to evaluate designs for electromechanical time co-ordination devices—machines that could, for example, link a central clock in a factory office to hundreds of other satellite clocks distributed throughout a sprawling plant. His night job? To weave simultaneity into a theory of space, time, matter and energy that would change cosmology forever.
SIMULTANEITY NOW! EINSTEIN, RELATIVITY AND THE NEW REAL WORLD
A halo of grey hair standing on end as if charged at the scalp; a sage lost in thought standing before a chalkboard covered with indecipherable scribbled equations; the philosopher-saint standing before world leaders, arguing for universal peace. There are many iconic images of Albert Einstein that define the man and his legacy. His stature as one of the greatest scientists in human history, if not the greatest, makes him a central figure in our culture’s mythology. The Albert Einstein we hold dear is the one who fits our needs. This is Einstein the über-theorist, the man who saw into the fundamental structure of reality, the man living in a world of pure thought and pure abstraction. Einstein’s theory of relativity is held up as the epitome of pure science, an exploration of nature’s essence far from the clamour of day-to-day life. But in the culture of his own day, the questions framing young Einstein’s great achievement in relativity were not abstract. Instead they grew from bread-and-butter experiences that shaped his dail
y life. And within his own life, questions of time and simultaneity—manifest in the patent requests he saw every day—were explicitly paying for the young Einstein’s bread and butter.
It was during his years in the patent office from 1902 to 1909, before he could secure an academic position, that Einstein developed the ideas that would become the theory of relativity. A separate myth has grown around these years of Einstein’s life. In both popular accounts and in the stories we physicists hear in our training, Einstein’s time at the patent office was an idyll, an aside from his great effort to construct the theory of relativity. The patent office might as well have been a fast-food restaurant, a place to kill time and make money while the real training was going on at home. The truth, however, is far more complex.
Simultaneity was a central issue for Einstein in the development of relativity. What does it mean to say that two events occur at the same time (as, for example, two trains pulling into two widely separated stations)? In physics textbooks the issue of simultaneity is usually presented as part of the general, abstract formalism of relativity theory. In the crucial years at the patent office, however, when the young Einstein was working out the key features of relativity, his concern with simultaneity was anything but abstract.
FIGURE 5.3. The Zytglogge in Bern, Switzerland (c. 1905), with its fifteenth-century astronomical clock. All the clocks in this city where Einstein worked as a patent clerk were connected and synchronized via electrical signals.
For these seven years, Einstein spent his days picking over the details of electromechanical time synchronization patents. It was the mechanics of synchronizing clocks via electromagnetic pulses that filled his mind during the workday. At home in the evenings, it was the theoretical mechanics of time, electromagnetic waves and simultaneity that consumed him, driving him forward towards a revolutionary new physics of time.
THE ELECTROMAGNETIC PARADOX: RIDING THE FRAME OF REFERENCE
When Einstein first arrived at the patent office, he had a physics paradox already stuck in his mind like a burr. He could not know it then, but he would have to rebuild time itself to pull the burr free. With patent evaluation work keeping him enmeshed in the real world, Einstein struggled to see through the tangled theoretical machinery of his era’s physics and gain purchase on a new vision of time and space.
The story begins not with grand abstractions such as time in and of itself but with the nuts and bolts of electromagnetic theory. Just eighteen years before Einstein was born, the British theoretical physicist James Clerk Maxwell gave physicists a set of equations linking all electric phenomena (charge, current, etc.) with magnetic phenomena (bar magnets, magnetic fields from moving charges, etc.). Maxwell had unified the domains of electricity and magnetism into a new field called electromagnetism. Considered a masterpiece, his consolidation of seemingly disparate phenomena into an underlying whole became an archetype for physics that persists even to this day.
Out of Maxwell’s famous unifying equations came an explanation of light as an electromagnetic wave. Physicists were well versed in dealing with waves. They had studied their properties in everything from the windblown ripples of water in a pond to the periodic compressions of air molecules that form sound waves. But what Maxwell’s equations made clear was that the visible light our eyes respond to is nothing more than waves of crossed electric and magnetic fields travelling through space at the tremendous speed of 300,000 kilometres per second (670 million miles an hour).
Just as water molecules slosh back and forth, supporting passing water waves, scientists expected that some medium existed to support electromagnetic (light) waves. Since light crossed vast distances between stars, they imagined an all-pervading “luminiferous aether” that filled the space between, supporting the light waves. While there was no direct evidence of the aether, physicists were certain it existed. Entire textbooks of theory were even devoted to the luminiferous aether and its physical properties.
FIGURE 5.4. Einstein at the Swiss patent office around 1905, the year he published his paper on the special theory of relativity. Rather than being simply a day job, Einstein’s patent work dealt with core issues of time and synchronization.
Maxwell, electromagnetic waves and the aether were all relatively new science when the teenage Einstein began his hungry exploration of physics. It was in these early years that he found an unanswerable question in Maxwell’s account of light—an enigma that would follow the young man like a shadow all the way to the patent office each day.
“What would it look like”, the young Einstein asked himself, “if I could ride a light wave?” A stationary observer watching a beam of light pass would see a train of wave crests rocket by, one after the other. But Einstein recognized that an observer riding the light beam, like a surfer catching the crest of an ocean wave, would look back and see nothing more than a wave frozen in space. No such frozen light wave had ever been observed. It was not part of the vocabulary of physics. More important, Einstein convinced himself that Maxwell’s equations ruled out even the possible existence of such frozen light waves. Thus he found himself caught between a theoretical rock and mathematical hard place. He had a paradox on his hands.19
Einstein’s dilemma rested on frames of reference. A frame of reference is the perspective, or platform, that constitutes an observer’s account of the world. If you are standing in a field watching clouds pass by overhead, that is one frame of reference. If you are sitting in an aeroplane a mile in the air and moving at five hundred miles per hour as you watch the same clouds, you have a different frame of reference. Since the time of Galileo and Newton, physicists understood that the motion of a frame of reference could affect the outcome of experiments performed within that frame. Doing physics correctly meant being mindful of reference frames and their motion.
Slam your foot down on your car’s accelerator and you will feel your body pressed backwards into the seat as the car surges forward. Blacken all the windows and you would still know that the car, your frame of reference, was accelerating. You would not need to see outside to confirm this because your body would feel the effects of the car’s acceleration. Now imagine the car is moving at constant speed on a smooth road (with perfect shock absorbers—no bouncing, shimmying or road noise). Could you still tell if you were moving? If you couldn’t look out the window, how would you determine your state of motion? Thus, some kinds of motion (acceleration) lead to effects you can measure with experiments, while others (constant velocity) do not affect experiments.
Over the years physicists learned how to shift their perspective back and forth between moving and stationary frames of reference and how to reconcile the different descriptions of physics each would observe. But Einstein’s paradox hinged on the inability to shift between frames of reference. In the frame at rest relative to his light beam he “saw” a passing electromagnetic wave. In the frame riding with the light beam he “saw” a frozen wave. The two frames had two different descriptions of the light beam, and no physics could reconcile them.
While Einstein was developing his ideas on light and reference frames, other physicists were attacking the same problem for reasons of their own. By the end of the nineteenth century the all-pervasive luminiferous aether was in trouble and scientists across the world were struggling to save it.
In the late 1880s two American physicists, Albert Michelson and Edward Morley, tried to detect the aether in a new way. The idea was to use the Earth’s motion through the aether as it orbited the sun. Their careful experiment was designed to pick up differences in the speed of light as the Earth moved through the background aether.20 By bouncing light waves back and forth in directions aligned with, and perpendicular, to the Earth’s motion, differences in travel times should have been detectable. The same effect occurs for motorboats on a choppy day when the wind drives strong waves on the water. Observers in the boat see the waves travelling with a different speed if they move with the wind (and the waves), or at some angle to the wind. But the Miche
lson-Morley experiment failed to detect any difference in light’s speed no matter which way the Earth travelled.21 It was as if the aether was not there, a conclusion few physicists in 1900 could conceive of without horror.
Some of the greatest physicists of the generation just ahead of Einstein had tackled the refusal of light to show any reference-frame-dependent changes in speed. Henri Poincaré, a giant of theoretical physics at the time, had taken the problem to heart. A mathematician of the highest calibre, Poincaré was deeply concerned with utilizing real-world applications of science in the French effort to create a globe-spanning grid of electrosynchronized longitude. Poincaré was also a strong proponent of the aether.22 His efforts, along with those of other physicists such as Hendrik Lorentz of the Netherlands and George FitzGerald of Ireland, focused on saving the aether by allowing for a more flexible meaning of measurement when it came to light and its velocity.
To determine the speed of an object such as a bullet, you really need to measure two separate quantities: length and duration. Length would be the distance the bullet travels and duration would be the time it takes the bullet to cover that distance. Poincaré, Lorentz and FitzGerald developed new laws for lengths and durations between frames of reference. These laws allowed measurements for both to stretch or contract depending on the object’s motion relative to the aether. If length and duration changed in just the right way, then the measured speed of light (length divided by duration) would always be the same. With this so-called length contraction and time dilation, the Michelson-Morley results were explained and the cherished luminiferous aether preserved.
DEATH OF THE AETHER, BIRTH OF SPECIAL RELATIVITY
Einstein did not care for the aether and so he did not care about saving it.
