From Live Science:
Today is the first day of spring in the Northern Hemisphere. It 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.
Read more ....
No comments:
Post a Comment