Every Day Is Special: September 23 - Autumn Begins with the Equinox in Eastern Asia

September 23 - Autumn Begins with the Equinox in Eastern Asia

Posted on September 23, 2021

This post is an updated version of my post published on September 23, 2010:

Equinox means “equal night,” and this is the date when day and night are equal lengths. (Depending on where you live, the day and night aren't quite equal.) In the Northern Hemisphere, fall begins on the September Equinox, and in the Southern Hemisphere, spring begins on that day.

This year the Equinox occurs at 19:21 UTC (Coordinated Universal Time) - on September 22! (That translates to 7:21 p.m. UTC.) Coordinated Universal Time is a time standard that can be referred to worldwide. It is based on International Atomic Time and is roughly the same time as Greenwich Mean Time, which is the time kept at the Royal Observatory, Greenwich, England.

Notice: today is September 23. And I just said that this year the September Equinox is September 22. What - what - what?

Well, any part of the world that has a time zone far enough ahead of UTC will have its Equinox early in the morning on the 23rd instead of in the afternoon or evening of the 22nd. So we say that the September Equinox occurs a day later in such locations as Eastern Russia, Japan, Korea, etc.

Fall falls...

Again speaking from the perspective of the Northern Hemisphere, the days have been getting shorter, and the nights longer, ever since the first day of summer. The days will continue to get shorter and shorter until mid-December. Today is the mid-point in the process.

The shorter days are the main reason that winter is colder than summer. This seasonal change is caused by the Earth's tilt.

Balance an egg on its end...

...or not...

Even though it has been disproved over and over (and over!), there persists a myth that you can balance an egg on its end only during an equinox, when everything is balanced and equal.

Some people might say that it's impossible to balance an egg - but it's not. It's really hard to do it—it takes a lot of practice—and it takes a lot of patience—AND you have to have the right egg, one that has a yolk centered in its shell—but you most definitely can balance an egg on its end.

However, with the right egg, with all that practice and patience, you can stand an egg on its end any day of the year! The idea that it is only possible on an equinox is pure myth!