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| Oh remember how short my time is:
For what vanity hast thou created all the children of men! Ps 89:47 |
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TIME fact 1:TIME: part 1
of 9
What is time (besides a weekly news magazine)? That is too difficult a question to
be answered effectively. Over the next several days we will look at man's varying attempts
to measure time. This is somewhat important to the Daily Miscellany so that we can decide
when a new day occurs and to record the occurrence of birthdays and events. The
measurement of time has led to a number of problems. Significant changes have been made in
the calendar over the ages. The years of 45 BC, 1582 AD, and 1752 were among the many
years of calendar changes.
Different cultures measure time differently. The dates of birthdays and events listed on
the Daily Miscellany may differ from those that appear elsewhere. On October 24, 1996, I
was lambasted in a letter for failing to list the remembrance of the assassination of
Prime Minister Yitzhak Rabin a year earlier. At first I did not understand the complaint.
My sources had the date for the assassination as November 4, 1995. With a closer look into
the situation I discovered the mistake. This person was remembering the date as it
occurred on the Jewish calendar (11th of Cheshva). Indeed the horrible event did occur on
the 11th of Cheshva, and one year later on the Jewish calendar corresponded to October 24,
1996 on the Gregorian calendar.
This event was not forgotten, but was listed 11 days later on the Daily Miscellany
(November 4, 1996). One can see how easily the dates of events and birthdays can be said
to be listed incorrectly. One year made a difference of 11 days - depending on what
calendar was used.
Scientifically, time can be measured in three ways.
Rotational time is based on the unit of the mean solar day. A solar day for the earth is
the length of time it takes the earth to complete one rotation around its axis.
Dynamic time uses the motion of the moon and planets to measure time. This measurement of
time avoids the problems associated with the Earth's varying rotation. The first dynamic
time-scale was proposed in 1896. This scale was know as Ephemeris Time. It was modified in
1960.
Atomic time is a third way to measure the passage of time. This method is based on the
regular oscillations that occur within atoms. In 1967 a basic unit of atomic time was
established. An atomic second is the length of time in which 9,192,631,770 vibrations are
emitted by a hot cesium atom. Atomic clocks are now used as international time standards.
Sources: The Handy Science Answer Book - Visible Ink |
