First Day Of Spring 2010 USA Date & Time?

Springtime is upon us with some nice sunny weather, pretty flowers, and lots of birds chirping and animals coming out of hibernation.

The first day of spring 2010 is much awaited after the long and cold winter season. The past winter has witnessed some huge blizzards and snow storms, and it is very refreshing to see the snow melt away and see the trees bloom.

While today is the first day of spring, the vernal equinox is when the earth tilt is perpendicular to its orbit around the sun.

Call it what you like – the vernal equinox, the Spring equinox, or merely Saturday – March 20 marks the first day of Spring for folks in the northern hemisphere.

I'm interested in the first day of spring date and time, I want to know when is exactly the first day of spring in the USA.

Can you guys let me know the date and time?

The official start to the first day of the new season is technically at 1:32pm EST

Astronomically, of course, the Spring equinox (and its Fall counterpart) marks the moment when the center of the sun's disk appears directly overhead at the Equator.

The first day of Spring is marked by the Vernal Equinox, which means the sun is supposed to sit exactly vertical above the equator.

The Vernal equinox is a natural phenomenon that takes place twice a year – once in March and the other in September – which signals the beginning of Spring and Autumn respectively.

Technically, the vernal equinox happens when the center of the sun is directly above the equator. Hence, night and day will be of almost equal duration.

Since the sun is above the equator, the length of the day and the night is the same. Equinox is Latin and means "equal night". For us in the northern hemisphere, that means each day will have more light and less dark! The exact time of the vernal equinox 2010 is 12:32 PM EST on March 20th.

If the sun were just a tiny point of light and Earth had no atmosphere, then day and night would each be exactly 12 hours long on a spring equinox day.The vernal equinox, however, occurs when the center of the sun crosses the Equator.Therefore, on the vernal equinox day, the daylight hours are actually longer than the length of time between when the sun crosses the horizon at dawn and when the sun crosses the horizon at sunset.

We know that the earth rotates about itself and it is tilted at an angle of approximately 23.44 degrees. It also revolves around the sun in an elliptical orbit. Because of the tilt of the earth, for the whole year, the sun shines at different altitudes above the horizon as viewed from earth.