Page 54 - Encyclopedia Of World History Vol V

time, conceptions of 1831

And bathed every veyne in swich licour

Of which vertu engendred is the flour;
Today we know the time without ever looking at the sun;
Whan Zephyrus eek with his sweete breeth we encounter jet lag as we fly from one time zone to
another; and we know not only the time here but the
Inspired hath in every holt and heeth
time there: we know when the stock market opens in
The tendre croppes, and the yonge sonne New York or in Tokyo and the difference between clocks
in London and Paris.
Hath in the Ram his halve cours yronne,
And smale foweles make melodye, From Absolute
to Relative Time
That slepen al the nyght with open ye
Study of the relationship between time and motion
(So priketh hem nature in hir corages); extends at least as far back as Greek philosophy. For
example, to Plato time was “the moving image” of an
Thanne longen folk to goon on pilgrimages.
ideal static eternity, manifested in and even brought into
Source: Davis, J. (1988). Libyan politics: tribe and revolution: an account of the Zuwaya
and their government (pp. 65-66). Berkeley: University of California Press. being by the motion of celestial bodies. Aristotle ques-
tioned this identity, seeing time rather as a “numbering”
of motion, dependent on perception of change. Augus-
tine, drawing on this tradition, suggested that this per-
ception implies a human observer, who by memory and
in 1872, but it was not until 1883 that a proposal by expectation may circumvent the apparent fact that only
William Allen, a U.S. senator, was finally adopted the present is in any sense real.
(smaller Britain had adopted Greenwich time much ear- With the invention of the mechanical clock, the regu-
lier, in 1840). Sandford Fleming, a Scottish-Canadian lar motion of the heavens could be represented in
inventor and engineer, argued in 1876 for worldwide miniature—figuratively, but also directly, as public clocks
rationalization, setting out the key features of the system by the late fourteenth century might also elaborately dis-
we use today. Inevitably, the same battles were fought as play the phase of the moon or the movement of the plan-
fiercely between nations, culminating in the Prime Merid- ets. It is then only a short step to a view of the whole
ian Conference of 1884, which adopted an international universe as a clockwork machine, put forward for exam-
system of standard time zones, but more crucially selected ple by Kepler and Boyle and a key feature of the seven-
Greenwich as the prime or reference meridian. It is well teenth century scientific revolution. Newton, developing
documented that commerce largely dictated this choice, the views of Isaac Barrow, famously stated at the begin-
in particular the dominance of shipping charts based on ning of Principia that “absolute, true and mathematical
Greenwich, which harkened back to the seventeenth cen- time, of itself, and from its own nature, flows equably
tury, when British astronomers and clockmakers vied to without relation to anything external.” Both the stars and
solve the problem of determining longitude at sea. the clock merely count off the flow of this absolute time,
In the twentieth century, ever more precise clocks which may be represented geometrically by a straight
began to reveal that the Earth’s rotation was not com- timeline with each point a single instant.
pletely regular.The first atomic clocks were developed in Leaving aside philosophical disputes, Newton’s defi-
the 1950s, and in 1967 the international definition of the nition survived unchallenged for over two hundred
second was changed so that the cesium atom is now our years, until Einstein. Einstein’s theory of relativity begins
primary timekeeper. Coordinated Universal Time is the with two postulates: Physical laws should not depend on
modern descendant of Greenwich Mean Time, but refers any motion of the observer, and the speed of light is the
instead to an international network of atomic clocks. same for all observers. The second jars with everyday