September 22, 2006Every year in September the sun crosses
the Equator and day and night fall into
The event is known as the autumnal equinox, and it
marks the beginning of fall in the Northern Hemisphere. The crossing
happens only one other time, at the start of spring, when it is
called the vernal equinox. Around the world, day and night are roughly the same length during an equinox.
See the celestial dance that
creates this phenomenon, then step back in time to find out how ancient
cultures—from the Druids to the Inca—incorporated the astronomical
event into their beliefs.