An equinox is not the shortest day. It has the same amount of daylight and darkness. The solstices have the longest and shortest days. The winter solstice is the shortest day of the year in terms of the amount of daylight.
Autumnal equinox
Although equinox means equal night, it doesn't mean that the day and night exactly the same. They are close. After the autumnal equinox the days are shorter though.
In 2011, the Autumnal Equinox begins on September 23rd.
September 22
In the Northern hemisphere, daylight hours decrease after the autumnal equinox.
The longest day and shortest night occurs on the summer solstice. The shortest day and longest night occurs on the winter solstice. Midway between these points (2x a year) are the equinox, where the day and night are of equal length.
Autumnal Equinox was 23. September in 1978
Google it. Or read what I have wrote: An Autumnal equinox occurs on September 2. It is a day when the day time approximately equals night time.
Both.
The autumnal equinox is also known as the fall equinox and the September equinox. An example of a sentence using "autumnal equinox" is "This year's autumnal equinox falls on a full moon. "
Autumn
12 hours
Autumnal equinox
the autumnal equinox
The autumnal equinox.
The equinox happens on Sept. 22. It marks the first day of autumn.
Although equinox means equal night, it doesn't mean that the day and night exactly the same. They are close. After the autumnal equinox the days are shorter though.