Time, The Earth’s Rotation and the Clock
Watchers.
When the year 2000 approached, the population of personal
computer owners became privy to some intriguing information:
operating systems are dependent on time. Whereas some people
predicted the end of the world, others were confident that
software gurus and computer nerds would safely deliver us into
the second millennium. The latter proved to be a reliable assumption.
While Y2K passed with not so much of a bump in most people’s
daily lives, the general population embarked on a new understanding
of computers and network systems: those plastic boxes are only
as good as their makers.
Now that fears of Y2K are long gone, another provocative force
of nature is threatening our computer world: unpredictable
day length. Time is a unit of measurement based on the earth’s
rotation and its orbit around the sun. Our daily lives are
scheduled by faith in this fact. Unfortunately, the earth’s
timing isn’t always predictable.
The Real Time
In the eighteenth century, astronomers believed the earth was
slowing down. In the nineteen thirties, the invention of
a quartz clock - the most accurate clock of that time - proved
that the earth was in fact slowing down 1.5 milliseconds
per one day per century. To deal with this problem the “leap
second” was invented and put to work in the 1970’s.
The leap second is used to coordinate international time
scales with the actual speed the earth is rotating. The first
leap second was added June 30, 1972. However, in 1999 the
earth started speeding up as mysteriously as it had started
slowing down.
According to WIRED magazine, April 2004, unpredictable day
length has catastrophic implications to our computer world.
Deep into the age of technology, most of our daily activities
are maintained by the operation of computers. If computers
are not properly programmed to handle the advent time adjustments,
information could be lost or confused. This is especially important
in cases of financial transactions, document transmissions,
and traffic control. Also without an accurate time system GPS
navigation or Global Positioning System used for could not
function. GPS is used to accurately determine the precise location
and time for a given person or place. GPS is used by anyone
from the United States Department of Defense to recreational
hikers. GPS is the most accurate way to locate a person lost
at sea.
The Time Keepers
Atomic clocks, in various places on the globe, are responsible
for measuring time. Atomic clocks, first invented in 1955,
use the electromagnetic radiation emissions to measure
time. Coordinated Universal Time or UTC is a reference
time scale based on the measurements of these atomic clocks.
UT1 is based on astronomical time or the exact time it
takes the earth to rotate. The leap second is used to coordinate
UTC with UT1.
January 1, 1999 marked the last time a leap second had
been introduced to UTC. There are many institutes and
organization at work to keep time dependable. The U.S.
Naval Observatory is responsible for the master time
in the United States. International time is maintained
by the BIH in France. The National Institute of Science
and Technology keeps frequency standards for the United
States. All organizations work in cooperation with each
other to ensure that international time is coordinated,
maintained and all functioning to the same international
standards.
Why and What For?
There are a lot of reasons why the earth is not perfectly synchronized
with our expectations. The gravitational pull of the moon,
the shifting of hot magma in earth’s core, or even
melting of ice at the earth’s poles could all influence
the speed of earth’s rotation. Even El Nino has been
attributed as causing a slower rotation. Still, the precise
reason behind why the earth is speeding up is still not known.
NASA explains how natural phenomenon can affect the earth’s
rotation:
“To understand how air currents can affect earth
rotation, you have to consider the ice skater on the ice
doing a spin.
If she changes how far she holds her hands by just a little,
it affects how rapidly she spins. Air currents change their
location on the earth, and their distance from the earth's
center by a few miles, and they also carry thousands or even
millions of tons of air in clouds. It is easy to understand
from this how, with conservation of angular momentum, the earth's
spin is constantly changing.”
What to do with Time
AWe can’t control Mother Nature. What we can do is maintain
time and data accordingly.
Currently, new and improved atomic clocks are being constructed
to surpass their already accurate predecessors. By visiting
the National Institute of Standards and Technology, website,
anyone can synchronize their personal computer with the correct
time.
For more information:
www.usno.navy.mil United
States Navy Observatory
www.worldtimeserver.com/ World
Time Facts, Australia
www.nist.gov/ National
Institute of Standards and Technology
www.ptb.de/en/org/4/43/432/index_en.html Germany’s
Time Keepers
www.obspm.fr/ The Paris
Observatory in France
www.nasa.gov National Aeronautics
and Space Administration
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