Autumnal Equinox 2010: Facts On The First Day of Fall

Autumnal Equinox 2010: Facts On The First Day of Fall
The autumnal equinox, or fall equinox. But do not be fooled by the idea that the autumnal equinox the length of day is exactly equal to the length of the night.
The true days of day-night level are always after the autumn equinox, before the spring, or spring, equinox, according to Geoff Chester, a public affairs specialist with the U.S. Naval Observatory in Washington, DC
The difference is a matter of geometry, atmosphere, and language.