Sunday, March 21, 2010

Vernal Equinox--It's Officially Spring...

...but this is the sight that greeted me when I looked out my office window the morning of the spring equinox.  A fresh overnight snowfall that continued through the day.

Equinox translates literally to "equal night."

On March 20, 2010, at precisely 1:32pm Eastern Daylight Time the sun crossed directly over the Earth's equator. That moment is known as the vernal equinox in the Northern Hemisphere announcing the arrival of spring and the autumnal equinox in the Southern Hemisphere announcing the arrival of fall. A second equinox will occur on September 22, 2010, at 11:09pm Eastern Daylight Time.

The fact that the Earth has distinctive seasons is due to the 23.4 degree tilt of the Earth's axis. The Earth receives more sunlight (longer daylight hours) in the summer and less sunlight (fewer daylight hours) in the winter. The tilt of the axis makes the seasons opposite in the Northern and Southern Hemisphere. At the north pole summer gives six months of daylight while at the same time the south pole is experiencing six months of darkness. The closer you are to the equator, the daily hours of daylight and darkness become more equal.

The fall and spring equinoxes are the only two times during the year when the sun rises due east and sets due west. Modern astronomy aside, people have recognized the astronomical connection to the season changes for thousands of years. The ancients of various civilizations all over the world built structures that illustrate this—temples dedicated to their various gods that modern man recognize as observatories. Not only the spring and fall equinox days, but also the summer and winter solstice days.

I think it's also interesting to note a connection between the spring equinox and Groundhog Day (a holiday derived from the practices and celebrations of the ancients). If the groundhog sees his shadow on February 2, we have six more weeks of winter. And by "coincidence" that six weeks takes us to within a few days of the spring equinox.


Annette Snyder said...

after groundhog day, isn't spring always six more weeks? those men in top hats have it right! anything to celebrate especially when winter is still hanging out!

susan said...

Know what you mean about spring..we never think of a true spring until after April as we have had snow in April quite a few times in the past. Sorry you woke up to that white stuff again. We are sure to get more before we are done this year. ha susan L.

Samantha Gentry said...

Annette: You're right. Nothing like a litle bit of celebrating to help those additional six weeks go by. :)

Samantha Gentry said...

Susan: This has definitely been one strange winter. We're looking at a 20 degree drop in high temperature between today and tomorrow. But, fortunately, tomorrow's daytime will be above freezing. Night time, however, is still below freezing. I'll be glad when spring kicks in for real...leaves on the trees, green grass, and some colorful flowers.