A second is 1/86,400 (60 seconds * 60 minutes * 24 hours = 86,400 seconds) of a solar day. A solar day is the time it takes the sun to go between two given points. The standard unit, the second, is divided by 10 into .1 (tenths) of a second, .01 (hundredths) of a second, and .001 (thousandths )of a second (also called a milisecond.)
How Time is Measured
The earth is divided into 24 time zones, each of which
is centered on a meridian line. Meridian are sometimes called "hour lines"because the earth turns 15 degrees in one hour.
See the table below for current times around the world.
Click here to see a map of time zones around the world.
Time can be measured in three ways: rotational time, dynamic time, and atomic time. Rotational time is based on the average length of the time it takes the Earth to complete one rotation around its axis. Dynamic uses the motion of the moon and planets to determine time. This method has the advantage of not having to use the inconsistent Earth rotation. Atomic time uses an atomic clock, and is based on the regular movements of atoms. Atomic clocks are now used as the international time standards.
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