What Is The Autumnal Equinox. The autumnal equinox is when the sun crosses the equator from north to south. What is the vernal equinox also known as?

On earth, there are two equinoxes every year: Autumnal equinox, two moments in the year when the sun is exactly above the equator and day and night are of equal length; August (small) 17 thursday end time: