By Paul g. Wiegman
Sunday, September 30, 2007

Fall arrived officially at 4:51 a.m., Eastern Daylight Time, on the 23rd of September. Last Sunday.I highlighted that event, and especially the date, to point out that fall doesn’t always begin on the 21st of September. It can fall anywhere between the 21st and the 23rd.

The more important fact when considering the beginning of autumn is that it is when the sun is directly above the earth’s equator as the tilt of the planet is moving away from the sun. That means, for everyone on the planet, that the day will have light and darkness of equal lengths.

Well, nearly equal lengths.   full story