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Topper's Blog, Spring,Vernal Equinox

4:57 PM, Mar 18, 2013   |    comments
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Vernal Equinox

Astronomical spring arrives on today, the 20th at 7:02 AM. This is the Vernal Equinox when the sun is directly over the equator which creates equal day and night in each hemisphere. Just so you know you can stand an egg on its end any time of the year. The sun directly overhead doesn't change any gravitational pull down here on earth as far as the egg is concerned. The Vernal Equinox marks the beginning of astronomical spring.  We go into spring while the southern hemisphere heads into fall. You might ask why the sunrise and sunset times are not exactly twelve hours apart on the first day of spring. The earth's atmosphere bends the light so there is not exactly twelve hours between the sunrise and sunset today. As we move toward summer the sun's angle will continue to rise. The angle of the sun is the key to climate. Yes, the days get longer and the jet streams retreat to the north but the angle of the sun is what drives climate. The higher the angle, the more overhead, the stronger the sun's rays will be. Todays sun is the equivalent of September sun so start using the sun screen. You might also be asking yourself why it's not the same time and same day every year. The solar year is about 365 and a quarter days so the time and date of spring and of all of the seasons can vary about a day or so. March came in like a lamb let's hope it goes out like one.

 

The Cherry Blossom Festival begins today and runs through April fourteenth, more on the festival tomorrow.