How do you think about time? How
do you define time? Answering these
questions becomes a humiliating, humbling, and at the same time, an astonishing ethereal
experience. In the process you find yourself
nearly paralyzed by being forced to simultaneously face ancient history and eternity. Clearly it is an infinite project. But by limiting ourselves to major
historical developments in mans time keeping, with a few obscure fascinations added,
there is an unfolding understanding of everyday terms we seldom question such as
the calendar, the year, the month, the week, the day, the hour, the minute and the second. Fundamental historical changes of time focus and
definition have taken place with earthshaking violence, and at other times with barely
perceptible comprehension. The future is
currently being molded by mind disturbing heated arguments about time, which will result
in quantum dislocations as significant as the Copernican and Galilean discoveries.
What is time? This is a subject we all have pondered. Time is a queer phenomenon. We all seem to experience it, use it liberally to
coordinate and organize activities and arrange nature in advantageous manners, yet we
cannot describe its essence with any sense of absolute certainty. Because of its nebulous nature, time is quite
pliable as a construct. We use symbolic
constructs to enculture and incorporate useful attributes of the time-thing in
our individual and collective consciousness. 1. So what is time? Websters New Unabridged Dictionary, seemed a logical place to search
for answers. But alas it contains no
less than 50 lineal inches of definitions! We
could hardly make a dent if we had a full fortnight of solid time. Solid time? Some how we know what solid time is or do we? If we think of making time solid in a generic
sense we immediately run into problems. The
more one tangles with defining time, the more ethereal and unfathomable it becomes. With the plethora of definitions, it is no wonder
St. Augustine of Hippo (350-430AD) had this to say: What is time? If nobody asks me I know, but if someone asks me,
clearly I do not know. 2.
Clearly or unclearly, we will discuss some
interesting aspects of time. To start with,
it appears that the way we measure time is illogical. Considering how old time is, you would think that we could have done a much
better job of choosing our units. I can
hardly think of a more illogical system. Why
must we have 12 months in a year? Ten or
twenty would make more sense. It not only
seems we are stuck with a 12-month year but also with a seven-day week! What strange fate of fortune came up with a number
like that? I think that a five-day week
would be much better. (Particularly if we could still have two days off for each weekend) Then in the dim and distant past insult was added
to injury by someone coming up with the crazy idea of subdividing the day into 24 hours! Twenty hours for each day would be much better.
We could then have 10 hours for the day and 10 for the night. Units of measure to the base 10 are much easer. Think of how much quicker children could tell
time. (Tell time now that is an
interesting thought. We all do it without a
single tinge of confusion). But what is it that we are telling? We tell something about something that we cannot
taste, hear, see, touch or weigh. We cant
speed it up, slow it down or stop it. Yet somehow we can tell it. Ah yes, I can year you say what we do in telling
time is to measure it. Measure something we
cant taste, hear, see, touch or weigh -- slow down, speed up or stop? How strange!
Yet we do it without a second thought.
The word second brings me back to the original train of thought. We were mentioning our crazy 24-hour day. When it became necessary to measure time in
smaller quantities, the least that could have been done was to use the decimal system in
dividing the hour into 100 parts. But no,
someone thought that sixty would be nice. Irrationality
continued with dividing the minute into sixty seconds.
To be logical the second needs to be divided into sixty parts. But it appears that reason finally won (most of
the time) by the division of the second into tenths, hundredths, thousands etc.
We also have this incongruous idea of saving time by
the use of Daylight Saving Time. We can thank
Benjamin Franklin with that idea. Actually we
dont save time at all as if we could -- considering its ephemeral nature. It took a long time for the idea to catch on. Daylight Saving Time was taken up seriously
during World War 1 to conserve fuel for electrical power.
During the Second World War, it was reinstated for similar reasons and
then it stuck. Dr. Arthur Young, professor
Emeritus of Astronomy at San Diego State University, writing in the Griffith Observer,
recalls a radio interview he gave. At its
close a lady called in complaining that Daylight Saving Time wasnt right because it
wasnt Gods time.3. We have all heard of Universal Time, Standard Time, Sidereal Time, and
Daylight Saving Time now we have Gods Time! In a cosmic perspective there is a major
snarl in trying to sort out Gods Time
In the context of Daylight Saving Time, it would be much easier
to assume that by this she was speaking of Sun Time. i.e., using the sun as a time
keeper. The uniform motion of the sun would
appear to be a perfect way to keep time. The
sun dial comes immediately to mind. But even
the ancient astronomers such as Hipparchus, knew there lurked problems with the idea of
uniform sun time. They knew that the number
of days between the vernal equinox and the autumnal equinox was 186 days and the number of
days between the autumnal equinox and the vernal equinox was 179 days. This was referred to as the anomaly. It told them that the motion of the sun somehow
was not uniform as everyone has assumed it to be. It
took many centuries before the explanation for this anomaly to be understood. The Aristotelian
Perfection of the Spheres was so instilled in scientific
and philosophical thought, that it was years after the great scientific convulsion of
Copernicus and Galileo before it was discovered that the earths orbit around the sun
was not a perfect circle, but rather an ellipse! This
means that there is a time when the earth is close to the sun called perihelion and
a time when it is away from the sun aphelion. Because of the laws of gravity, the earths speed through space
is fastest at perihelion (nearest to the sun) and slowest at aphelion (greatest distance
from the sun). This results in the number of
days from the beginning of spring to the beginning of autumn to shrink seven days between
the beginning of autumn to the beginning of spring. Thus, even a perfectly constructed sun
dial is not going to run at the same rate from one day to the next. In yesteryear this was not a significant problem,
but as more and more precise means of time keeping were available, this became a problem
of major significance. 4.
So another definition of time comes into history
called mean time. Sundials
had to be converted to mean time. This
was done by application of an equation called the equation of time. This takes into consideration not only the varying
speed of the earth around the sun, but also its rotation on its own axis, and the fact
that the axis of the earths rotation is tilted in reference to its orbital plane
around the sun.5.
Without getting further into the consequences of
these verities of celestial mechanics, there are some curious effects this has on times of
sunset and sunrise. A dramatic example of
this effect is the winter solstice on Dec 21 the shortest day of the year. Over half of my life slipped by before I realized
that the shortest day was not because the sun came up the latest on that day and set the
earliest on the same day. Actually the
earliest sun set is on Dec 7 and the latest sunrise is on Jan 4! It is the combination of these two effects
that overlap, resulting in the shortest day falling on Dec 21.6.
There is another way of defining time -- through
Einsteins famous E=MC2 equation. I
am surprised there is not more discussion on this curious subject. Rearranging the formula using fundamental algebra
one can state that C2=E/M. Since C
is speed we can define it as D/T, so our equation becomes D2/T2 =
E/M. Making another algebraic transform we
find that T = DvM/E. So there we have it, the
ethereal thing called time, which has qualities we cant taste, see, hear, feel,
touch or weight defined in terms with which we are comfortable -- distance, mass, and
energy, which are all everyday well understood entities. All this is possible provided we understand that we have done a little
slight of hand. It is true that C is speed
which is defined as D/T, but this is a very special kind of speed. It is the speed of light. So at this unique speed, the tangible replaces the
intangible. So perhaps we inadvertently found
Gods time defined at this somewhat mystical velocity.
So what time is it? Is it sundial time, mean solar time,
sidereal time, local solar time, Daylight Saving Time or Gods time? But leaving this aside for now you will recall
that this discussion began with objections to the way time intervals are measured. All of this is the result of embedded historical
inertia -- currently so encrusted, that even though scientifically we would be better off
to discard our present system it is too late. So we have 12 months to a year, approximately 30 days to a month, 7
days to a week, 24 hours to a day, 60 minutes to an hour and 60 seconds to a minute. Where did all this come from?
About 3000 B.C., the ancient Sumerians developed
official calendars based on the 29 ½ day moon cycle. This was adopted by the Babylonians and Egyptians. The lunar month as a unit of time keeping is
actually the origin of many interesting words we commonly use without understanding their
historical background. Since primeval times
there has been a connection of the moon with measurement.
It turns out that the word moon in English and its cognate
in other languages is rooted in the word me conveying the idea of measurement. The Greek word is metron from which we
get our English word meter and the word measure. It is also the root of the late Greek word menolgion,
which is the contracture of two words meno meaning month and logy meaning account. It is directly from this we have our English word
menology referring to a calendar and is included in the title of this paper. The word calendar derives from the Latin calendarium meaning account book since it was used to keep track of the dates when accounts were due. Interestingly enough, the word menstrual is the
same cognate me which curiously has a cycle close to the moons cycle. Not to belabor the base 10 decimal system, I
cannot help pointing out that the human gestation period is 10 lunar months. So the moon figures importantly in the historical
measurement of time, but unfortunately it is not useful for farmers and hunters that need
a calendar for the seasons --
to predict hot and cold. This is because moon cycles do not match up with solar cycles,
which has resulted in a lot of thinking and tinkering trying to get things to come out
So long as man marked his life only by the cycles of
nature the changing seasons, the waxing or waning moon he remained a
prisoner of nature. So he devised his own
bunching of time. These bunches were markedly
varied but were generally cyclic. From
this the Week originated. This
is no western invention and it has not always been seven days. At least 15 different ways of bunching time into
weeks have been used. These have
varied from 1 to 20 days in length. The shorter week periods have been found in Africa and
the longest in Mesoamerica. The
Kedangese of eastern Indonesia are the creative record setters when it comes to
fabricating week cycles. They have ten kinds
ranging in length from 1- 10 days, each with its own set of names, all running at the same
time. Furthermore, they seem to be able to
calculate in their heads when every conceivable combination will recur in the maze of
cycles that eternally preoccupies them.8.
How then did we come to have a seven day week? Apparently the Greeks had no week. Romans lived by an 8-day week. Farmers worked the fields for 7 days and came into
the city on the eighth day the market day. When
and why they fixed on 8 days is not entirely clear and when and why they changed to a
7-days week is not clear. The number 7 has
had a magical charm in many cultures. The
Japanese had seven gods of happiness, Rome was set on seven hills, there were Seven
Wonders of the World, medieval Christians enumerated seven deadly sins, we have the seven
ages of man and Islam has their seventh heaven. And that is not the end. There are the seven deacons, the Greek legend of
the Seven Against Tebes, the Seven Champions of Christendom, the Seven Churches in the
book of Revelation, Seven Sages of Rome, the Seven Seas, and The Seven Sisters in the
constellation Pleiades. There is the early
Christian legend of the Seven Sleepers, and the Seven Virtues. And there is the popular
superstition of the Seventh son. He is
supposed to be lucky with occult powers. From
this comes the seventh son of the seventh son a potent magician. So it should come as no surprise that we have a
seven day week. No known edict, however, is
known for the Roman transfer to 7 days. It apparently happened about the early third
century A.D.; about the time Christianity was accepted into the Roman Empire by
Constantine in 325 A.D. The Christians
had brought the Jewish week with them including the naming of the 7th day
Sabbath. This seems to have survived from the
years when the Jews were in Babylonian captivity. The
Babylonians observed certain enumerated days the seventh, fourteenth, nineteenth,
twenty-first and the twenty-eight day when certain activities were forbidden.9.
Then there is another bunching of time which is near
and dear to this group -- our fortnight. The
oldest reference to this term I could find is in the Oxford English Dictionary that
references its Germanic use in Laws of Ina page 55 where the word
feowertyne niht occurs in the year 1000AD. We
now use it as a contracture of fourteen and night two weeks of nights. In 1530 it was still spelled with a u
but by 1639 the u was dropped in an article appearing in the Hamilton
Papers. It is altogether fitting then,
that we meet in the twilight hours to measure our passage of time, in terms of nights
rather than days.
So much for weeks and fortnights the month
most certainly relates to lunar cycles. If
there were exactly 12 lunar cycles in a solar year things would have been much easier, but
as we have mentioned the lunar cycles dont fit the solar cycle. We know the Egyptians divided the solar year into
12 months. Their 12 lunar cycles that
made up their lunar year come to 354 days roughly eleven days short of the seasonal
year. This was solved by adding an extra
month about every third year or so.10. For a while they came up with an interesting variation to have just
three weeks for their month, but each week containing 10 days giving them a 30 day month. But of course this didnt come out right at
the end of the year either, so they added some extra days at the end for having parties.
The Persians who had commerce and exchange of ideas with Egyptians also had 12 months of
30 days each. But they differed from the
Egyptians by having their months divided up into two seven day weeks and two 8 day weeks. This arrangement gave them 5 intercalary days at
years end like the Egyptians.11. The ancient Jewish astronomers while in
Babylonian captivity based their year on the movement of the sun, their months on phases
of the moon and gave Babylonian names to their months.
They departed drastically, however, from the Babylonians and Egyptians
by making some of their months full with 30 days, and some of their months
defective with 29 days. To get
the lunar cycles to keep pace with the solar cycle they threw in a thirteenth month every
third, sixth, eight, eleventh, fourteenth, seventeenth, and nineteenth years. This gave them an underlying 19 year cycle
which did a good job of keeping things in order.12.
The formation and history of calendars in different
civilizations is a fascinating subject but before leaving this subject, mention now is
made of the unique Mayan calendar. The
Mayans of Central America used not only the sun and moon, but also the planet Venus to
establish a 260 day and a 365 day calendar.13.
These cyclic systems were intermeshed like interlocking gear trains. By
turning these two cyclic systems backward they left a celestial-cycle record indicating
their belief that the creation of the world began in 3113 B.C. because that is when both
cycles simultaneously reach zero. This is of
interest, as it is not too different from Ushers chronology of the earths age.
The hour glass was developed as a relatively accurate
means of recording time. It was independent
of weather and very useful when at sea on a rocking boat. It was this instrument that lead to determining a ships speed at sea. To calculate the speed one would throw a piece of
wood overboard with a knotted rope attached. The
knots were seven fathoms apart and one just counted the number of knots that passed
through their fingers in a minute. This then,
is the derivation of the ships speed being measured in knots. 14.
Our present calendar dates back to 1582 when there
was a convergence of political and religious tension over the problem that came up in
regard to the date of Easter as it was determined by the calendar used in the western
world up until this time, called the Julian Calendar. This old calendar was replaced by Pope Gregory XIII and is known
as the new calendar or the Gregorian calendar. This was worked out by a large number of mathematicians and
astronomers. The Julian calendar by this time was 10 days out of synchronization with
astronomical time and required some radical changes. Actually three changes were made: the
calculation of leap years was changed by eliminating three leap years every four
Centuries, taking 10 days from the month of October, and beginning the New Year on January
1 instead of March the first, as it had been in the Julian calendar. What Pope Gregory thought was going to be a
relatively easy task turned out to be much different. The Eastern Orthodox Church refused to accept it and if it hadnt been
for the Bolshevik revolution the Russians probably would still be using the Julian
calendar. Their revolution of 1918 changed
all that, ushering in the new Gregorian calendar. It is ironic that the revolution with all its
secular overtones would abandon the secular Julian calendar for a calendar initiated by a
religious system. Spain and Italy as it
turned out accepted the new calendar within 2 years.
France came on board sometime later as there was a lot of trouble with
the University of Paris where the theologians resisted the idea. Their belief system held that the church was
perfect and correct in all things, including the old calendar, always supported by the
church. To them it was an admission that the
church had been wrong. It would be
interesting indeed to know in detail the debates that ensued, and how resolution of their
faith system finally occurred. The group for
which perhaps we should feel the most sympathy, however, was the Spanish army of Flanders. They had ten days of their pay stopped to
compensate for the time lost in the new calendar. Amazingly
the transfer took place almost immediately in China, where the Jesuit missionaries won
approval of the new calendar from the imperial observatory in Beijing.
As one might expect things did not go as well in
Protestant Europe. It was not until 1699 that
Germany took up the new calendar. This was
not without considerable difficulty as many of the population observed religious holidays
in accordance with the old calendar. As
Elector Maximillian I gained more power in support of the Pope, many Germans were sent to
prison for non-observance of the new calendar. The
Anglican Church in England, the Calvinists in Switzerland and the Netherlands, the
Lutherans in Scandinavia and Germany considered the new calendar to be diabolical. Imagine, if you can, how it could have been, that
something as inert as time became demonic! England
didnt accept the new calendar until 1752, 169 years after its introduction. The world looks back on the resistance of the
Copernican and Galilean scientific insight by the church institution as an example of
unacceptable intolerance. But when the same
church introduces something as neutral as calendrical reform, it is met with unmitigated
hostility. Robert Mandrow comments that the
introduction of the modern calendrical system was a fine example of the
subordination of scientific work to the dogmatic requirement of institutional systems. 15.
We turn now from the broad calendrical measurement of
time to the shorter divisions of the day. The
division of the day into 24 hours is possibly related to ancient people measuring the
height of the sun in the sky by holding their hand outstretched in front of their faces
and marking off the number of spans. It turns
out that there are 24 spans in a complete day.
There is conflicting information as to how 60 divided the hours and
minutes. The division by 60 dates from the
Babylonians who attributed mystical significance to this number. They used the sexsgisimal system of numbers, based
on multiples of sixty. But at this point the
scent of origin becomes weak as their use of the number sixty seems to have nothing to do
with astronomy or the movement of heavenly bodies.
The detail of development of time keeping, in the
shorter segments, is colorful and fascinating. We
will dip briefly into a few of the major developments. Candles were used throughout history but had serious problems with
non-uniform burning rates. An improvement was
the water clock. These were basically a
container filled with water with a small opening in the bottom. The oldest one so far, was found in the Egyptian
tomb of Amenhotep I, from about 1500 BC. These
had great inaccuracies as well as you can imagine because of deposits occluding or
narrowing the opening.
Undoubtedly the most magnificent and accurate water
clock ever made was by Su Sung in China. Magnificent
because of its size and accurate because it incorporated a water driven escapement
mechanism. He built this device in 1088 AD
based on water driven escapements invented about 725 AD long before anything approaching
an escapement came out in the western world. It
was housed in a pagoda-like tower, measuring 30-40 feet in height. The now published details show it was very
complicated, with many revolving parts and a succession of gear trains. The escapement mechanism, hitherto regarded as an
exclusive European invention, rotated 100 times every 24 hours. This water driven clock had a highly sophisticated
ingenious arrangement for tripping the scoops into which the water flowed ensuring a
uniform pressure in the water system itself. The
mechanism included a bronze power-driven armillary sphere, an automatically rotating
celestial globe, and five panels with doors that opened permitting a look at the changing
manikins which rang bells or gongs, and held tablets indicting the hour or other special
times of the day.
This elaborate clock was not the whim of an inventive
genius, but rather to take care of an especially intimate need for the Emperor himself. Every night as the Emperor consorted in his
bedchamber he had to know the movements and positions of the constellations at every hour
in precisely the way Su Sungs Heavenly Clockwork made possible. In China the ages of individuals and their
astrological destinies were calculated not form the hour of birth but from the hour of
When Su Sung constructed his imperial clock,
the emperor had as attendants a large number of wives and concubines of various ranks. These women totaled 121 (one-third of 365, to the
nearest round number), including one empress, three consorts, nine spouses, twenty-seven
concubines, and eighty-one assistant concubines.
Their rotation of duty, as described in the Record of Rites
of the Chou dynasty, was as follows: The
lower ranking women came first, the higher-ranking came last. The assistant concubines, eighty-one in number,
share the imperial couch nine nights in groups of nine.
The concubines, twenty-seven in number, are allotted three nights in
groups of nine. The nine spouses and the
three consorts are allotted one night to each group and empress also alone one night. On the fifteenth day of every month the sequence
is complete, after which it repeats it reverse order.
By this arrangement, the women of highest rank would lie with the
Emperor on the nights nearest to the full moon, when the Yin, or female, influence would
be most potent, and so best able to match to potent Yang, or male force of the Son Heaven. So timely a combination, it was believed, would
assure the strongest virtues in the children when conceived. The main function of the women of lower ranks was
to nourish the Emperors Yang with their Yin.
But that was not all. A corps of secretarial ladies kept the records of the Emperors cohabitation with their brush dipped in imperial vermilion. The proper order of these proceedings in the imperial bedchamber was
believed essential to the larger order and well-being of the empire. During Su Sungs time it was lamented that in
earlier years, particularly during the disorderly days of the ninth century, that the
ancient tradition of nine ordinary companions every night, and empress for two night
at the time of the full moon was no longer respected, with the result that all the three
thousand palace women were in complete confusion.
The need for an accurate clock, to show the position
of the heavenly bodies at each moment of the day or night, was then obvious, to ensure the
best-qualified succession of emperors. The
ruling houses of China did not follow the rule of primogeniture. In theory, only the sons of the empress could
become emperor, but this usually left the emperor with a number of young princes from whom
to choose his heir. A prudent emperor was
bound to give close attention to the astrological omens at the precise moment when each
prince was conceived. To record these facts
accurately was the duty of the secretarial ladies with their vermilion brushes. The astronomical observations and mechanical
calculations of Su Sungs Heavenly Clockwork provided that data for these records and
prognostications, and so were of great political significance.16. 17. 18. 19.
Although Su Sungs gear driven water clock is
probably the oldest large escapement clock, the oldest gear driven clock work goes to the
Greeks about 1000 year earlier. This
is known as the Antikythera mechanism found in 200 feet of water in a shipwreck off the
Greek island Antikythera. The positions of
the stopped gears and dating of the associated artifacts in the ship, date the ships
sinking to 80 BC. Its mechanism is like a
modern analogue computer which uses mechanical parts to save tedious calculations dealing
with astronomical events truly a monument to Greek science. There are inscriptions recording 76 years,
19 years This refers to the well-known Calippic cycle of 76 years, which is four
times the Metonic cycle of 19 years, or 235 synodic (lunar) months. (These cycles deal
with the problem of synchronizing the lunar cycles with the solar cycle as mentioned
earlier.) The next line includes the number
223 which refers to the eclipse cycle of 223 lunar months.20..
Turning our attention now to Western
Europe, we find sketchy references to Monk Gerbert who became Pope Sylvester II, inventing
the first mechanical clock in 996. There
is good documentation of large mechanical clocks beginning to appear in the early 14th century in several Italian cities. Unfortunately
no models or records of earlier clocks exist. They
were subject to inaccuracies similar to water clocks as the rate of speed was dependent on
the driving weight and amount of friction in the drive. Only two clocks of that century remain in working order to this day. One is
the great clock in Strasbourg France built in 1352 and the other in Salisbury England
built in 1386.
The next advance was spring driven clocks invented
between 1503 and 1510 by Peter Henlein. They
only had an hour hand. It wasnt until
1577 that the first minute hand was put in place for the great astronomer, Tycho Brahe, in
order to track the stars more accurately. Minute
hands did not commonly appear until the 1670. There
was no glass in front of the hands until the 17th century. Reasonably accurate clocks had to await the
pendulum. It was Galileo who conceptually
invented the pendulum clock in 1592, but it was not actually put into a clock until 1656
by Christian Huygens. Huygens clocks
eventually achieved an accuracy of less than 10 seconds/day. In 1721 George Graham improved pendulum accuracy
to 1 sec/day by devising a pendulum that was insensitive to an increase in length by
temperature. He then financed John Harrisons
development of a marine chronometer to an accuracy of 1/5 of one second per day capable of
determining longitude to within ½ of a degree after a voyage to the West Indies. He collected the British governments prize
for this invention -- a reward equivalent to over $2,000,000 dollars in todays
At this point I would like you to recall
my previous Fortnightly paper on Nathaniel Bowditch. One of his major contributions was a means of determining longitude at sea
by use of lunar observations.23. Actually
by the time he died, John Harrisons chronometer was invented. There was a major
problem, however, with these clocks. Very few
shipping companies could afford them, as their cost exceeded the cost of several ships. So shooting the moon overlapped the
chronometer for several decades in the determination of longitude.
During this period, the compulsion of accurate time
keeping became more and more acute. By
the late eighteenth century the word punctuality appears in our language to
describe the habit of being in good time. Clocks became master of daily life. By 1760 when Laurence Sterne wrote his
mock-heroic Life and Opinions of Tristram Shandy, he
opened his saga with the most modern possible interruption of his conception. At the crucial moment, when Tristrams mother
and father were in bed and Tristram was about to be conceived this is recorded: Pray, my dear, quoth my mother, have
you not forgot to wind up the clock? Good God! cried my father. Did ever woman, since the creation of the
world, interrupt a man with such a silly question?24.
By 1889 pendulum clocks achieved an accuracy of 1/100
sec/day and became the standard time keepers in observatories. One of the most famous was the W. H. Sort clock
developed in 1921 that had two pendulums. one was a slave and the other the master. The quartz clock came next, between 1930 and
1940. These clocks were more accurate than
the pendulum clocks and could be worn as a watch on the wrist, but there was a drawback. The oscillation frequency of the quartz crystal
depends critically on the shape and size of the crystal, which is technically difficult to
control. Thus it is not possible to have
consistency from one clock to another.
Tuning forks need to be mentioned for historical
completeness, but received only a short period of popularity.
The next major breakthrough came with the invention
of the atomic clock of which the cesium clock is the most popular. It has gone through 7 levels of improvement
reaching, in 1999, the ability of neither gaining nor loosing a second in 20 million
years! But even before this accuracy was
achieved the cesium atomic clock had redefined the second.
This was in 1968 when the second, previously defined in terms of the
earths rotation was redefined as 9,192,631,770 cycles/second of the cesium atom. Before this change in 1968 our time was referred
to earth time beginning at the Greenwich meridian in England, known as Greenwich Mean Time
(GMT). This was used as the means of
determining longitude through out the world. But
with the precision of atomic clocks the problem of coordinating earth time with the new
definition of the second became highly unsatisfactory.
This was because the rotation motion of the earth fluctuates by a few
thousandth of a second per day. A compromise
time scale was eventually devised, and on January 1, 1972 the new Coordinated Universal
Time (UTC) became effective. This time runs
at the rate of cesium clocks. The earths
rotation, however, is not only erratic but has a mean rotational difference. When the difference between atomic time and earths
rotational time approaches one second, a one-second adjustment (a leap second) is made in UTC,
thereby maintaining synchronization. So the
compromise is that earth retains its primacy for date-time, while actual elapsed time
(laboratory time) is demarcated by the cesium atomic clock.
As miraculous as this accuracy is, the Jet Propulsion
Laboratory, right next to us in Pasadena, is working on a mercury atomic clock which when
operated in an orbiting satellite in 2005 will have only one second variation in 300
million years. Hard on the heals of this
advance, follows the rubidium clock that promises to provide an unimaginable accuracy of
one-second in three billion years! 25.
With accuracies of this magnitude you would think
that additional precision would come to an end, but dont count on it. While time itself remains a poorly
understood phenomenon, the measure of techno-scientific sophistication of various
civilizations can be seen to correlate with their achievement in time measuring
technologies. How a society measures time
reflects a juncture of its needs, goals, and the current level of technical achievement. Time measurement technology is a cluster
technology that sits toward the center of other techno-scientific activity. It permits the building of complex activity
interactions between people, their environment, and Nature.
Consequently, measuring time with increasing accuracy, in smaller
increment, and in varying contexts has been the predominating theme for innovation.26.
During the days of the quartz clock, scientists found
variations of rate of spin of the earth. This
is attributed to such things as wind friction against the earths surface, the
deposition of water as ice and snow at higher latitudes and altitudes in winter, and the
tidal pull of the moon. Not only do these factors vary the rate of the earths spin,
but also cause the spin to be slowly slowing down. The rate of slowing is 1 second in 500
years. It has also been found that the
distance between the moon and the earth increases by 4 cm each year. This combination of features will eventually lead
to synchronous rotation. At that time the
moon will constantly remain over a fixed point on the earths surface. This situation already exists in our solar system
between the planet Pluto and its satellite Charon. 27.
We are all familiar with the four time zones that
divide the United States. There are 24 around
the entire circumference of the world. These
are based on 15 degree segments measured at the equator. The historical explanation of time zones lies with the railroads in the
United States. Until a train could travel
hundreds of miles in a single day there was no real problem. But time changes about one minute for every 12 ½ miles traveled east or west. Each major city
had its own local time. This created major
problems with the railroad trying to coordinate over 300 local times. A partial solution came with the establishment of
100 time zones by 1883. This was still too
complex for people and goods moving at increasing speeds.
So in the year 1883 the United States divided itself into 4 time zones
centered on the 75th, 90th, 105th, and the 120th
meridians. Then at noon on Nov 18,
1883, telegraph lines transmitted GMT to the cities within each zone. The authorities of the cities within each zone
adjusted all their clocks to the same time. The
next year on November 1, 1884, the International Meridian Conference met in Washington DC
and applied the same procedure all around the world.28.
After all the trouble humans have had with this
time-thing it is incongruous that serious modern physicists and astrophysicists have come
up with sound reasons why there is no such thing as time.29. So it seems we have come full circle. The ancients intense study of the heavens to
come up with ways to measure time and develop various calendars, is abandoned by use of
cesium, mercury and rubidium. Then, of all
things, we find ourselves in 2003, told there is no such thing as time! I dont know where all this is taking us, but
I for one am concerned about the 50 inches of time definitions that Webster has giving us.
Duke Ellington, Jazz pianist, composer and conductor
who died in 1974 was in agreement with this modern thought when he told us he didnt
need time. I think he had it right when he
said, I dont need time. What
I need is a dead line.
: The author is a full time Pathologist and medical
director of the Department of Pathology at Redlands Community Hospital. He has been with the hospital and lived in
Redlands for the past 38 years. His hobbies
are Astronomy, Amateur Radio, Sailing, Travel, Reading, and Grandchildren.
- Clocks, A
Symbolic Construct. Internet.
Observer. Vol. 67, No 2, p.2 Feb, 2003.
Observer. Vol. 67, No.2, p.2, Feb, 2003.
Observer. Vol.67, No.2, p.5, Feb, 2003.
Observer. Vol.67, No.2, p.9, Feb,2003
Observer. Vol.67, No.2, pp.15-17. Feb, 2003.
- The Discoverers.
p.4, Daniel Boorstin. Random House, 1985
- Empires of Time.
p.101, Anthony Aveni. Harper Collins, 1989.
- The Discoverers.
pp.13,14. Daniel J. Boorstin. Random House, 1985.
- Griffith Observer.
Vol.67, No.5, p.7, Feb 2003.
- The Story of Civilization. Durant. Vol. IV, p.138.
- The Story of Civilization. Durant. Vol. IV,
- Empires of Time. pp. 185-252, Anthony Avini.
Harper Collins, 1989.
- The Discoverers. p.34, Daniel J. Boorstin. Random
- Ten Days
that Shook the World by Trevor Johnson on the Gregorian Calendar and Europes wars of
religion. Internet: Wavelength 12 ten days that shook to world.
- Escapement Clock. NATURE, Mar 31, 1956. p.601.
- A Working Model of the Mechanical Escapement in Su
Sungs Astronomical Clock Tower. NATURE,
Sept 28, 1963. pp. 1241-1244.
- The Chinese Water Balance Escapement. NATURE, Dec
19, 1964. pp1175f.
- The Discoverers. pp. 66-63, 76-77. Daniel J. Boorstin. Random House, 1985.
- An Ancient Greek Computer. SCIENTIFIC AMERICAN June 1959, pp.60-67.
from the Greeks. The Antikythera Mechanism
A Calendar Computer from 80 BC. Derek
De Solla Price. Amer Philosophic Society.
- The Discoverers.
p.398, Daniel J. Boorstin. Random House, 1985.
- Longitude -- The True Story of a Lone Genius Who Solved the Greatest Scientific Problem
of His Time. Dava Sobel. Walker Publishing Co. 1995.
- Americas First Mathematician, Astronomer and Philosopher: Nathaniel Bowditch. W.
Leonard Taylor M.D. The Fortnightly Club. Meeting Number 1649, March 29, 2001.
- The Discoverers. p.72, Daniel J. Boorstin. Random House. 1985.
- Griffith Observer. Vol. 67, No.5, pp.17-18., May 2003.
- Space and Time A Human Condition Internet.
- Astronomy. p.73, March 2002.
- Griffith Observer. Vol. 67, No.5, p.15, May 2003.
- The End of Time. The Next Revolution in Physics, Julian Barbour. Oxford University