The weather outside may not yet be frightful, but the slight chill in the air is indicative that summer is coming to an end. Indeed, the first day of autumn is not only just around the corner, but it is tomorrow, September 22.
The seasons change on the day of the autumnal equinox, the second of two equinoxes each year.
What exactly is an equinox and what does it signify? Each year, the planet Earth goes through two equinoxes and two solstices. The equinoxes occur in September and March, marking the start of fall and spring, respectively. The soltices occur in June and December, marking the start of summer and winter.
Confused? So were we, until we consulted the National Aeronautics and Space Administration, known more popularly as NASA.
“An equinox occurs midway between the two solstices when the days and nights are the least equal,” NASA said in a statement.
The autumnal equinox also marks the point at which darkness will start to be more prevalent than daylight. Since the summer solstice in June, the hours of daylight have been growing shorter and, on the day of the autumnal equinox, day and night are approximately equal in duration.
Indeed, the term “equinox” is a portmanteau combining the Latin word “aequus,” which means “equal,” and “nox,” which means “night.”
The days will continue to grow shorter and the nights will continue to grow longer until the winter solstice, which will take place on December 21. The winter solstice occurs when one of the Earth’s poles has its maximum tilt away from the Sun.
(Photo: Accura Media Group)