September 29, 2022

Fall equinox: Why the first day of fall isn’t as equal as you might think

7 min read


(CNN) — Twice a year, the sun doesn’t play favorites. Everyone on Earth is apparently on equal footing — at least when it comes to the amount of light and darkness they receive.

We have entered our second and final equinox of 2022. If you live in the Northern Hemisphere, you know it as Autumnal Equinox (or Fall Season). For people living south of the equator, this equinox actually signals the arrival of spring.

Your location on the globe also determines whether you celebrate the day this year on Thursday, September 22 or Friday, September 23. People in America will celebrate it on Thursday. The time zone difference means that people in Africa, Europe and Asia will mark it on their Fridays.

People near the equator have about 12 hour days and 12 hour nights all year round, so they won’t really notice anything. But hardier people near the poles, in places like Alaska and the northern parts of Canada and Scandinavia, go through wild swings in the day/night ratio every year. They have long, dark winters followed by summers where night barely intervenes.

But during the equinox, everyone enjoys a 12-hour division of day and night from pole to pole. Well, there’s just one rub — it’s not quite as “equal” as you might have thought.

There’s a good explanation (science!) for why you don’t get it. Absolutely 12 hours of daylight on the equinox. More on that below.

But first, here are the answers to your other burning equinox questions:

Where does the word ‘equinox’ come from?

From us CNN Fast Facts File: The term equinox comes from the Latin word equinoxium, meaning “the equinox between day and night”.

When exactly is the autumn solstice?

The setting sun is seen looking west over Randolph Street in Chicago a few days before the autumnal equinox in 2019.

The setting sun is seen looking west over Randolph Street in Chicago a few days before the autumnal equinox in 2019.

Terrence Antonio James/Chicago Tribune/Getty Images

For people in places like Toronto and Washington DC, that’s 9:03pm local time. It arrives in Mexico City and Chicago at 8:03 p.m. Out west in San Diego and Vancouver, that means it will arrive at 6:03 p.m.

But head in the other direction across the Atlantic, and the time change puts you on Friday. For residents of Madrid, Berlin and Cairo, it falls at 3:03 a.m. on Friday. Heading farther east, Dubai marks the exact event at 5:03 a.m.

For Bangkok residents, it’s 8:03 a.m. while Tokyo is 10:03 a.m. Click here to see more cities. (rounded by one minute and adjusted for daylight saving time)

Is Fall the Official First Day of Fall?

Yes. Fall officially begins on the autumnal equinox.

But there are actually two scales of seasons: the “astronomical seasons” (which occur after the equinoxes and solstices) and the so-called “Seasonal weather.”

Alison Chanchar, CNN meteorologist, explains the differences:

“Astronomical autumn is basically the time from the autumnal equinox to the winter solstice. Those dates can vary by a day or two each year,” she says.

“Climatic autumn is different … in that the dates never change and are based on the meteorological seasons rather than the Earth’s angle to the sun. These are probably the seasons that most people are familiar with,” says Chancher.

At higher elevations, such as Kenosha Pass, Colorado, fall foliage may be early.  This photo was taken at night on September 19, 2016, illuminated by the moonlight and the headlights of a passing car.

At higher elevations, such as Kenosha Pass, Colorado, fall foliage may be early. This photo was taken at night on September 19, 2016, illuminated by the moonlight and the headlights of a passing car.

RJ Sangosti/Denver Post/Getty Images

The climatic seasons are defined as follows: March 1 to May 31 is spring. June 1 to August 31 is summer; September 1 to November 30 is autumn. And from December 1 to February 28 is winter.

“It makes some dates difficult,” Chancher says. “For example, December 10, most people would consider winter, but if you’re using the astronomical calendar, it’s technically still considered fall because it’s before winter.”

“Meteorologists and climatologists prefer to use a ‘climate calendar’ not only because the dates don’t change — making it easier to remember — but also because they know more about the traditional seasons,” he said. lets think.”

Why does decay occur in the first place?

The rising sun tries to break through the fog near Glastonbury, southwest England, in autumn 2021.

The rising sun tries to break through the fog near Glastonbury, southwest England, in autumn 2021.

Matt Cardy/Getty Images

The Earth rotates along an imaginary line that goes from the North Pole to the South Pole. This is called the axis, and this rotation gives us day and night.

However, the axis tilts at 23.5 degrees, As NASA explains.. This positions one hemisphere of the planet to receive more sunlight than the other in half a year’s orbit around the sun. It is this difference in sunlight that sets the seasons in motion.

Its effect is maximum in late June and late December. They are the solstices, and have the greatest difference between day and night, especially near the poles. (That’s why it’s so light each day during the summer in places like Scandinavia and Alaska.)

But since the summer solstice three months ago in June, you’ve noticed that our days in the Northern Hemisphere have been gradually getting shorter and nights longer. And now here we are at the autumnal equinox!

What did our ancestors know about all this?

Long before the age of watches, satellites and modern technology, our The ancient ancestors knew a lot. about the sun’s movement across the sky — enough to build massive monuments and temples that served as giant calendars to mark the seasons, among other purposes.

Here are just a few sites associated with the equinox and the annual passage of the sun:

Megalithic Temples of Malta: These seven temples on a Mediterranean island are some of the oldest free-standing stone buildings in the world, dating back 5,000 to 6,000 years. On Hajra Qom and Najdra The temples, semi-circular chambers, are aligned so that the sun rising at the equinox is framed between the stones.
Chichen Itza

Mexico’s Chichen Itza is sacred ground during the spring and autumn equinoxes.

Getty Images/zxvisua

Chichén Itzá (Yucatán Peninsula, Mexico): El Castillo, the famous pyramid of Chichén Itzá, puts on a spectacular show on equality. Built by the Toltec-Maya people Between 1050 and 1300, the pyramid was built to cast a shadow during the equinoxes on the northern balustrade of El Castillo. It resembles the figure of a snake slithering down a flight of stairs, and the archaic special effect is heightened by sculpted beast heads at the base.
Jantar Mantar (New Delhi, India): Originally much more recent (1724 and 1730), these late Mughal buildings are astronomical observatories.

What festivals, myths and rituals are still with us?

All over the world, the autumnal equinox has made its way into our cultures and traditions.

In Greek mythology, autumn marks the return of the equinox. Goddess Persephone In the Underworld for three months, where she is reunited with her husband, Hades.
Chinese and Vietnamese people Still celebrate the Harvest Moon (also known as the Mid-Autumn Festival). Lanterns line the streets as people give thanks, watch the moon and eat. Round pastries called mooncakes are a favorite at the Mid-Autumn Festival. It is held on the 15th day of the eighth lunar month on the Chinese calendar. In 2022, It fell on September 10.

Britain’s beloved harvest festivals have their roots in autumn since pagan times.

Autumn leaves of Rikogen, Tokyo

Tokyo’s Rikogen Gardens are ablaze with autumn color. Autumn is a national holiday in Japan.

Courtesy of Camon Berlin

Are the Northern Lights really more vibrant on the equinox?

Yes – they often put on more shows this time of year.

This suggests that the autumnal equinox and spring (or vernal) equinox usually coincide with peak activity of the aurora borealis.

So why isn’t the equinox exactly equal?

It turns out that depending on where you actually are on the planet, you get a little more daylight than darkness on the equinoxes. How does this happen? The answer is a bit complicated but interesting.

As The US National Weather Service explained.the “nearly” equal hours of day and night are the complex way that sunrise is measured and the refraction of sunlight in our atmosphere.
The evening sun shines through autumn-colored foliage on the chestnut trees along the Landwehrkanal in the Kreuzberg district of Berlin.

The evening sun shines through autumn-colored foliage on the chestnut trees along the Landwehrkanal in the Kreuzberg district of Berlin.

Stephen Zeitner/dpa/picture-alliance/AP

This bending of light rays causes the sun to appear above the horizon when the sun’s actual position is below the horizon. The day is slightly longer at higher latitudes than at the equator because it takes longer for the sun to rise and set the closer you get to the poles.

So on the autumnal equinox, the length of the day will depend on where you are. Here are a few breakdowns to give you a rough idea:

At or near the equator: about 12 hours and 6 minutes (Quito, Ecuador; Nairobi, Kenya; and Singapore)

• At or near 30 degrees north latitude: approximately 12 hours and 8 minutes (New Orleans, Louisiana; Cairo, Egypt; and Shanghai, China)

• At or near 60 degrees north latitude: approximately 12 hours and 16 minutes (Helsinki, Finland, and Anchorage, Alaska)

For a truly equal day/night division, you have to wait until a few days or weeks after the official equinox. That is the day. called equiluxand when it happens depends on your latitude.



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