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Posts Tagged ‘fall equinox’

Astronomical Fall

Posted in Science!, tagged , , , , , , , , on September 22, 2024| Leave a Comment »

Yesterday, we headed out into one of the many beautiful trail systems dotted around Ottawa. The day was bright and the paths were carpeted in a lovely array of gold, orange and red leaves. It felt like a perfect way to usher in fall, but it turns out we were a day early.

Today, however, we can celebrate the Autumn Equinox, when night and day are (more or less) equal, and the sun shines directly down streets set east to west, as they do in places like Chicago.

Autumnal equinox 2024 brings fall to the Northern Hemisphere today

When is the first day of fall in 2024?

A carefully worded answer is that on Sunday, Sept. 22, at 8:44 a.m. Eastern daylight time (5:44 a.m. Pacific daylight time) autumn begins astronomically in the Northern Hemisphere, and spring in the Southern. At that moment, the sun would be shining directly overhead as seen from a point in the equatorial Atlantic Ocean, 461 miles (743 km) south-southwest of Monrovia, Liberia. 

10 Things About the September Equinox

Here are 10 facts about the first day of astronomical fall (autumn) in the Northern Hemisphere.

Welcome to fall!

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Photo by John Jennings on Unsplash

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Turning to Fall

Posted in Holidays, Science!, tagged , , , , , , on September 23, 2023| Leave a Comment »

It’s that time again. If you are in the northern hemisphere on planet Earth, today is the Fall Equinox.

Autumnal Equinox 2023: First Day of Fall | Facts, Folklore & More | The Old Farmer’s Almanac

After the autumnal equinox, days become shorter than nights as the Sun continues to rise later and nightfall arrives earlier. This ends with the winter solstice, after which days start to grow longer once again. 

The word “equinox” comes from Latin aequus, meaning “equal,” and nox, ”night.” On the equinox, day and night are roughly equal in length.

Why just “roughly” equal in length?

Why day and night aren’t equal length on an equinox

Firstly, the sun has a size—it’s not just a point in the sky.… Secondly, the Earth’s atmosphere refracts (bends) sunlight.

What does the ebb and flow of axial luminescence look like from space?

NASA: Seeing Equinoxes and Solstices from Space

For more on the “why” of seasons, check out this explainer:

What Causes the Seasons? | NASA Space Place

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Photo by Alicia Petresc on Unsplash

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Welcome, Fall

Posted in Science!, tagged , , , , , , on September 22, 2022| Leave a Comment »

The winds are cooler, the rains no longer soft. Bird feeders empty faster and the flowers look defiant rather than content.

I love summer, of course, but there’s something special about a hot bowl of soup and a warm blanket and crisp blue days and brightly colored leaves.

It’s a wonderful time of year for just about anything, but especially for taking stock and making plans.

Welcome to Fall.

Autumn equinox is the first day of fall. How is that different from a solstice? : NPR

Fall starts at 9 p.m. ET Thursday, a day officially known as the autumn equinox.

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Twilight Surprise

The sky burns down,
A rim of coals glowing gold and red,
Limned with orange again
And kissed with hints of pink.
The clouds reflect tangerine and plum,
Overshadowing the silent glory.
Darkness and light,
Balanced upon this equinox,
Dance together like old lovers …
… and beget beauty.

― Elizabeth Barrette, From Nature’s Patient Hands

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Photo by Samuel Ferrara on Unsplash

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