Pre-1895
The Dawn of Time

To run any race you must know the course. To build a time machine you need to know what time is, just as you cannot fly without knowing the nature of air and aerodynamics. But understanding time is easier said than done.

A celebrated Zen riddle asks, when a tree falls in the forest and nobody is around, does it make a sound? This riddle can probably be applied to time. Would there be such a thing as minutes or years if no human beings could experience their passage?

This seems to be a very odd suggestion, but the nature of time is very strange. Indeed, it is a real puzzle for science. It forms an inescapable part of our lives yet cannot easily be defined. It has fascinated mankind since we first learned to communicate, but there have been no clear answers about its nature. Indeed, some great minds have argued that its measurement is purely a human invention.

Greek philosopher Zeno showed the problem when he tried to define a small unit of distance. To catch a tardy tortoise you can easily run twice as fast and halve the distance between you and the animal in a set period of time. But if you keep on halving the distance that gap will never equal zero, because half of something is always going to be a finite number, however small. But if there is always a gap between you and the tortoise it is impossible to ever catch up with it—a conclusion that we know to be absurd by practical experience, even if we have never actually chased a tortoise. A faster runner will always catch a slower one, sooner or later.

Time is intimately involved in this discussion—since speed is a measure of distance traveled in a set time. So we can apply Zeno's thinking and divide a second into smaller and smaller pieces. If we keep breaking down this gap, making the units half as long as the previous one, then there will always be a finite length for any moment that we can measure. But if that moment has any size at all, then part of it must be in what we think of as the past and part of it in the future because it will take time to pass any mark or point. We call this tiniest measurable moment "now" and say that it separates past from future. Yet how can it separate anything if parts of it lie simultaneously in both past and future?

Arguments still rage over the meaning of this curious riddle. Is it a fallacious argument—like the one concerning the tortoise? After all, it may look impossible to catch up with the animal but clearly we know that it is not, so the riddle is flawed in its execution. Others suggest that there may be something even more profound in this realization about time first made 2,500 years ago. Is the reason that we cannot clearly identify a moment that is neither past nor future a hint that past and future are a product of human imagination? Is the universe fundamentally timeless and is the distinction between past and future just an illusion brought about by our limited capacity to visualize the cosmos?

Virtually every human society that developed a culture has speculated in similarly bemused ways about the nature of time. The Greeks defined it as a measurement of intervals, which could be of long or short duration. As far back as 350 BC Aristotle had realized the implications of the Zeno paradox. But he had no better answer, and this choice to divide time into basic units, mirroring many mundane things that form a sequence, such as the human heartbeat, allowed for the creation of sundials, water clocks, and eventually mechanical clocks. We gained a feeling of mastery over time by recording it with increasing skill and so it came to be a powerful element in our lives.

St. Augustine, many centuries later, was a little bolder and dared to ask the question—what was God doing before He created the universe? If time was born along with the matter in the universe, as the Bible suggests, then was there any time before that instant, or is God somehow also to be considered timeless? Intriguingly, this question largely foresees modern scientific concerns about how the cosmos was first created—the subject of intense debate between physicists and astronomers.

There are two basic theories. One is the so-called Steady State idea that the universe has always existed in its present form, perhaps even made by God. British astrophysicist Fred Hoyle championed this theory though he also invented the name given to the rival theory—the Big Bang. He hoped that such a daft name would ridicule this alternative concept that says that everything in the universe emerged long ago from one single, tiny point that exploded outward and has gone on expanding across billions of years. But the Big Bang theory has gathered strong evidential support from modern science and is the widely accepted view today. Hoyle was proved wrong, but ironically, his name is attached to the theory that he so detested—the ultimate insult. Physics has had to conclude that time somehow began when the universe started to expand and before that instant there was neither matter nor time.

However, it was by no means clear to Renaissance thinkers that time emerged from the birth of the universe. Nor did they even accept that it was an essential requirement to make the laws of nature work. Indeed, the more that science began to comprehend these rules, the more it became aware that time, in our experience moving from the past into the future on a perpetual one-way journey, is not a prerequisite. In fact, virtually every law of physics seemed to work just as well if time flows backwards, moving from the future into the past. This realization enhanced suspicions that time might be a convenience of mind that made us see things as we do rather than a necessity of nature.

Different societies have other concepts of time and it is a mistake to imagine that our modern Western perspective, dominated by timetables and cell phones, is the only way to see things. We have grown up with this one version of reality but there are other, equally valid interpretations. The dreamtime, for instance, is an aboriginal concept still widespread in native Australian culture. It could not be further removed from twenty-first-century thinking and is extremely difficult to even translate. But, in essence, it regards past, present, and future as coexisting in a timeless void or hidden dimension beyond the range of our normal perception. For that reason, in dreams and other states of consciousness where we lose touch with the normal sense of awareness, we enter what is in effect another reality where things that once were, still are, and where things that will someday be, have already become.

Time spans the infinity of the cosmos and the tiniest moment that we can record. But it may not even exist. No wonder it is such a riddle. But it is important to follow the manner with which science has attempted to come to terms with time, piecing together its nature through a series of grand theories and experiments. For these are the stepping-stones upon which today's plans to build a time machine are all based.

Throughout the Renaissance, as scientists began to understand the nature of the physical world, there was an uneasy truce between what mattered to most human beings and the things that interested physicists. Galileo and Newton showed that all the planets of the solar system, including the Earth, rotate around the sun in a wonderful cosmic ballet. Their paths could be mathematically defined, to the point that Newton even argued that God created the universe as a vast clockwork machine that allowed everything that would ever happen to be mapped out into perpetuity. God had wound up the machinations of the cosmos and let it loose for mankind to discover its properties. By doing so we could make stunning calculations far into the future, because the speeds and times of the orbits of these planets could all be precisely delineated effectively forever.

It was these calculations that allowed NASA to work out how to send Apollo spacecraft to the moon, using sums that Newton could have easily done for them. The same rules allowed the rescue of fated mission, Apollo 13, sending it like a slingshot around the lunar surface and heading back to Earth thanks to the mathematics of the universe and its timeless precision.

However, as these findings seem to prove that ticking clocks were defined by the distant motion of bodies in space, science also found itself in open warfare. It battled religion, fearing that the mathematics of nature might replace the edicts of God. And it battled ordinary people who had always gauged time in simple ways—from observing the seasons, the growth of crops, and the calendars decreed by the church. Now scientists were saying that the only true way to measure time was to accurately describe how the Earth revolved around the sun and the exact time it took for our planet to rotate on its own axis. We had only ever been able to make guesses about such matters before and had inevitably miscalculated to some degree. Scientists wanted to put right those centuries-old mistakes and rearrange the timetable of our lives so that it was in balance with the motions of the universe.

In the 200 years leading up to the nineteenth century, ordinary folk were asked to rethink how they should now judge time. For centuries the year had been calculated as having 365 days plus one quarter of a day, hence the extra "leap year" day every four years, but this estimate based on the Earth's orbit was only approximate. As time had passed the year had slipped out of phase with the way our planet truly moves around the sun, and did so a little bit more each year. So by papal edict in 1582 the error was corrected and 11 days were dropped from the calendar. Such was the opposition to meddling with time that this "Gregorian" Calendar found favor only after a long period and with some decidedly odd consequences.

For instance, the area surrounding the city of Strasbourg accepted the decree immediately and changed over in November 1583. But the city itself stuck to the old calendar for another ninety-nine years—meaning that when it was New Year's Day in Strasbourg it was already the middle of January just a few miles away. The chaos that resulted is obvious, not to mention the apparent time traveling—by crossing the city line, you could walk "into the past."

In Britain workers protested that eleven days would be stolen from their earnings if they agreed to the plan imposed by Rome. Such "time riots," as this clash between science and the masses was dubbed, shows just how much concern was being expressed by the ordinary, then generally uneducated, person about any attempt to play with our long accepted way of viewing time. They delayed the introduction of the correctly aligned calendar in the United Kingdom until 1752, almost two centuries after much of Europe.

The old ways of thinking about time have not entirely gone away. For instance, on the Isle of Man in the Irish Sea (the world's oldest continuously operating parliamentary democracy) a ceremonial reading of laws to the public is still held at Tynwald Hill each year. It occurs on what would have been midsummer had those 11 days not been expunged two and a half centuries ago.

A crucial moment in the understanding of time came with the ability to measure the speed of light—although, when this happened it was not apparent that there was even a speed to be measured.

Copyright © 2005 by Jenny Randles