Happy Vernal Equinox.
The astronomical arrival of spring is a consequence of the earth’s tilt
on its axis as it orbits around the sun. Equinox from the Latin aequus (equal) and nox
(night) means the the earth’s two hemispheres are receiving the sun’s rays
equally. On this date the sun rises exactly due east and set
exactly due west with sunlight striking both hemispheres of the earth
equally. Night and day are approximately
equal in length.
As you observe the movement of the sun across the sky each day
you will note that it is shifting toward the north. Birds and butterflies begin their northward migration
as a response to this change in daylight following the path of the sun.
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| Stonehenge View West |
It
would be premature to pack-away your winter outerwear, return the snow
shovels to the shed or plant a garden. Nevertheless, this is a
harbinger of the arrival of astronomical spring for those of us in the
northern hemisphere.
The official start time will be today, March 20 at about 4.01 AM CST. Where I live at mid-northern latitude today the amount of daylight added to each day peaks at three minutes.
Astronomers
base season cycles upon the position of the earth in relation to the
sun. The beginning of Astronomical Spring or the Vernal Equinox marks
the time when the sun passes directly above the equator. Meteorological
spring is based-upon annual temperature cycles. Your weatherman will
tell you that meteorological spring begins March 1 and goes thru the
end of May.
No matter how you slice it the days will grow longer, the temperatures warmer and mud season is in full swing.
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