Thursday, March 19, 2009

The Science Of Spring


From Live Science:

The first day of spring is no guarantee of spring-like weather, but officially the season's start comes around at the same time each year nonetheless.

Well, sort of.

The first day of spring arrives on varying dates (from March 19-21) in different years for two reasons: Our year is not exactly an even number of days; and Earth's slightly noncircular orbit, plus the gravitational tug of the other planets, constantly changes our planet's orientation to the sun from year to year.

And weather-wise, Earth's seasons have shifted in the past 150 years or so, according to a study that came out last month. The hottest and coldest days of the years now are occurring almost two days earlier.

Read more ....

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