It’s fall. It came officially at 2:50 a.m. Saturday at what is known as the Autumnal Equinox or the first day of fall, because that is when day and night at the Equator are each 12 hours long, caused by the Earth’s spin as it orbits the sun.
That spin is not exactly vertical, instead the Earth has a spin axis of 23 ½ degrees, which produces not only night and day, but the seasons as well.
When the Earth’s axis points towards the sun, it is summer for that hemisphere; and when it points away from the sun, winter is the result.
The 23½ degree spin axis means neither the North Pole or South Pole ever point exactly at the sun, or completely away from the sun. However, in the summer the poles don’t see complete darkness, which is why Norway is often referred to as “The Land of the Midnight Sun.” In the winter, the poles don’t see complete daylight either.
Midway between summer and winter, the first day of spring and fall, the spin axis of the Earth points 90 degrees away from the sun, causing day and night to each be around 12 hours long.
Day and night are not exactly 12 hours long on the first day of spring or fall here in North America. That actually occurs a few days later, due to the latitude of your location.
For example, in Frankfort, which has a latitude of 38.2 degrees north, on Saturday, Sept. 23, sunrise was at 7:28 a.m., with sunset at 7:35 p.m. Tuesday, Sept. 26, is when day and night will be equal in length, with sunrise at 7:30 a.m., and sunset at 7:30 p.m. Your sunrise and sunset times will be a few minutes earlier or later, depending on if you are east or west of Frankfort. Of course, in the Central Time zone there will be an hour difference.
One question that often pops up is whether you can stand an uncooked egg on end during the day of spring or fall equinox. The National Weather Service says yes, adding that you can do it any day of the year, if you hold the egg still long enough for the liquid contents to settle before removing your hand.
(Here’s another explanation of standing an egg on its end from Scholastic.)
Tom Latek has been the Frankfort correspondent for Kentucky Today, the online news website of the Kentucky Baptist Convention, since 2016. Previously, he covered news for radio and television stations in Frankfort, Lexington, and Louisville.
