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Autumn Equinox 2019: 9 Things You Should Know About the First Day of Autumn



Autumn Equinox Comes: On Monday, September 23, both the Northern and Southern Hemispheres will experience the same amount of daylight.

For those of us in the Northern Hemisphere, it marks the beginning of astronomical decline, with daylight continuing to decline until the winter solstice in December. For those south of the equator is the beginning of spring.

Technically speaking, equinox occurs when the sun is straight in line with the equator. It will be at 3:50 AM Eastern on Monday.

The following is a brief scientific guide to the most even night of the season.

1) Why do we have equilibria?

The autumn and spring equinoxes, the seasons, and the changing daylight hours throughout the year are all due to one fact: Earth rotates on an inclined axis.

The slope – possibly caused by a massive object that struck Earth billions of years ago – means that for half a year, the North Pole is focused on the sun (as pictured below). For the other half of the year, the South Pole receives more light. That is why we have seasons.


NASA

Here's a demonstration of the time that has been set throughout the year from space. In the video you can see how the line separating the day from the night (called the terminator) swings back and forth from the poles throughout the year.


NASA / Meteosat / Robert Simon

Fun Terminator Fun: It's not like it divides the Earth into even halves of light and dark. This is because our atmosphere bends the sunlight a little, essentially stretching it over a slightly larger area than land. This "causes the earth covered by sunlight to have a larger area than the earth covered by darkness," NOAA explains. So stick to this simple, sweet thought: There is generally a little more daylight on Earth than darkness in general.

And here's another cool way to visualize the seasons. In 2013, a resident of Alberta, Canada, took this camera on a photo of the sun trajectory throughout the year and shared it with the EarthSky astronomy website. You can see the dramatic change in the rainbow from December to June.

This is a 6-month photo of the conclusions drawn from solstice to solstice, in Medical Hat, Alberta, Canada. We are one of the sunniest cities in Canada and it shows it beautifully.

Posted by Ian Hennes on Saturday, December 21, 2013.

(You can easily make a similar image at home. All you need is a can, photo paper, some tape and a pin. Instructions here.)

2) Is the equinox really the first day of autumn?

Well, it depends: are you asking a meteorologist or an astronomer?

Meteorologically speaking, summer is defined as the hottest three months of the year, winter is the coldest three months, and in between the months are spring and autumn.

Here's how NOAA breaks it down:

The meteorological spring includes March, April and May; meteorological summer includes June, July and August; meteorological fall includes September, October and November; and the meteorological winter includes December, January and February.

Astronomically speaking, yes, the fall begins when the Southern Hemisphere begins to receive more sunlight than the Northern Hemisphere. And that starts with the autumn equinox.

3) How many hours of daylight will I get on Monday?

Equinox literally means "equal night." And during the equinox, most places on Earth will see approximately 12 hours of daylight and 12 hours of darkness.

But not every place will experience exactly the same amount of daylight. For example, on Monday, Fairbanks, Alaska, will see 12 hours and 11 minutes of daylight. Key West, Florida, will see 12 hours and six minutes. The differences are due to how the sunlight breaks (bends) as it enters the Earth's atmosphere at different latitudes.

You may also notice that in both places the daylight is longer than 12 hours. Shouldn't day and night be equal? The daylight is slightly longer than the nighttime equinox due to the way we measure the length of the day: from the first hint of the sun peering over the horizon in the morning to the last glimpse of it before falling below the horizon in the evening. As the sun takes some time to rise and set, it adds a few minutes of daylight.

Check out TimeAndDate.com to see how many hours of sunlight you'll get during the equinox.

4) Can I balance only one egg on top of it during equinox?


This man balances eggs very well. AFP / Getty Images

You may have been told as a child that during equinox it is easier to balance an egg on a vertical surface than on other days of the year.

The practice originated in China as a tradition on the first day of spring in the Chinese lunar calendar in early February. According to the South China Morning Post, "The theory is that at this time of year, the moon and the earth are in the right alignment, the celestial bodies are generating the perfect balance of the forces needed for this."

This is a myth. The amount of sunlight we get during the day has no power over the gravitational pull of the Earth, nor does it have the ability to balance things on it. You can balance an egg at the end of it at any time of the year (if you're good at balancing things).

5) When do the leaves begin to change colors?


  Autumn foliage in the mountains.

Karen Bleier / AFP / Getty Images

As the days start to get shorter, the deciduous trees begin to signal on their leaves to stop producing chlorophyll, the green pigment responsible for color and photosynthesis. on the leaves.

Because the color change is more dependent on light than on temperature, this occurs essentially at the same time year after year, according to the US National Arboretum.

Temperature and meteorological conditions, though, can influence the intensity of falling colors and how long they linger. They can also slightly affect the time when the leaves begin to change. And drought can change the speed at which the leaves turn.

Because of all the variables in reproduction, it can be difficult to predict exactly when autumn colors will reach their maximum and how long they will last in a given area. But here's an exhilarating effort: The SmokyMountains.com website (a site promoting Smoky Mountains tourism) has created this interactive map (click on the link to play with it) to determine the colors of peak autumn sizes in the United States by county.

6) What is a pumpkin spice?

Pumpkin spice is not a single spice, but a mixture of them. And it does not contain pumpkin.

This Epicurious recipe includes cinnamon, ginger, spice, nutmeg and cloves. It's autumn – go ahead and sprinkle it with whatever you want.

7) Is there an ancient monument that does something cool during the equinox?

During the winter and summer solstices, the crowds flock to Stonehenge in the United Kingdom. During the solstice, the sun either rises or sets according to the layout of the monument of 5000 years. And while some flock to Stonehenge for the fall equinox, the real place is Mexico.

This is because the equinox pyramid in Chichen Itza on the Yucatan Peninsula makes a great show. Built by the Mayans about 1000 years ago, the pyramid is designed to cast a shadow over the equinox that outlines the body of Kukulkan, the feathered serpent god. The statue with the head of the snake is located at the bottom of the pyramid, and as the sun goes down on the day of the equinox, sunlight and shade show the body of the snake joining the head.

It's easier to see in a video. See below.

8) Are there equinoxes on other planets?

Yes! All the planets in our solar system rotate on an inclined axis and therefore have seasons. Some of these slopes are insignificant (such as Mercury, which slopes at 2.11 degrees). But others look more like Earth (23.5 degrees) or even more extreme (Uranus slopes 98 degrees!).

Below, see a beautiful composite image of Saturn on its equinox, taken by the Cassini spacecraft (RIP) in 2009. The gas giant slopes 27 degrees to the sun, and the planet's equilibria are rarer than on Earth . Saturn sees the equinox only once every 15 years (because it takes Saturn 29 years to complete an orbit around the sun)


Cassini / NASA Imaging Team

During the equinox of Saturn its rings become unusually dark . This is because these rings are only about 30 feet thick and when the light hits them with the head, there is not much surface to reflect.

9) I clicked on this article by accident and I really just want a mind-blowing picture of the sun


The sun threw a coronal mass ejection along with part of a solar filament for a three-hour period on February 24, 2015. Some of the filaments fell back into the sun.
Observatory for Solar Dynamics / NASA

The image above was taken by NASA's Solar Dynamics Observatory, a spaceship launched in 2010 for better understanding of the sun.

Last year, NASA released the Parker Solar Solar Probe, a spacecraft that will come 4 million miles from the Sun's surface (much closer than any spacecraft so far). The purpose is to study the atmosphere, weather and magnetism of the sun and to understand the mystery of why the sun's crown (its atmosphere) is much hotter than the surface. However, even at a few million miles, the probe will have to withstand temperatures of 2,500 degrees Fahrenheit.

It's important to understand the sun: there's nothing to mess with. Brad Plummer writes about Vox about what happens when the sun erupts and sends space time our way of destroying the Earth.


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