The equinox sun rises due east and units due west
The March 2023 equinox occurs on March 20, 2023, at 21:24 UTC (4:24 p.m. CDT).
The March equinox heralds the arrival of spring within the Northern Hemisphere and autumn within the Southern Hemisphere. As a matter of reality, on this day, the sun rises due east and units due west.
Even when that appears counterintuitive, it’s true regardless of the place you reside on Earth (besides on the North and South Poles, the place there is no such thing as a east or west).
The equinox sun and its place in space
To know the almost due-east and due-west rising and setting of an equinox sun, you need to consider the truth of Earth in space. First take into consideration why the sun’s path throughout our sky shifts from season to season. That’s as a result of our world is tilted on its axis with respect to its orbit across the sun.
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Now take into consideration what is an equinox. It’s an occasion that occurs on the imaginary dome of Earth’s sky. And it marks that particular second when the sun crosses the celestial equator going from one hemisphere to the opposite. In fact, it additionally represents a degree in Earth’s orbit.
The celestial equator
The celestial equator is a superb circle dividing the imaginary celestial sphere into its northern and southern hemispheres. Moreover, the celestial equator wraps the sky straight above Earth’s equator. Following the March equinox, the sun crosses the celestial equator to enter the sky’s northern hemisphere.
All these elements are imaginary, but what occurs at each equinox could be very actual. Actually, it’s as actual because the sun’s passage throughout the sky every day and as actual because the change of seasons.
It’s the identical all around the globe
So regardless of the place you’re on Earth (aside from the North and South Poles), you will have a due east and due west level in your horizon. That time marks the intersection of your horizon with the celestial equator, the imaginary nice circle above the true equator of Earth.
And that’s why the sun rises near due east and units near due west, for all of us, on the equinox. The actual fact is, the equinox sun is on the celestial equator. Which implies, regardless of the place you’re on Earth, the celestial equator intersects your horizon at due east and due west.
This reality makes the day of an equinox a great day for locating east and west out of your yard or favourite website for watching the sky. Simply go exterior round sundown or dawn and see the situation of the sun on the horizon with respect to acquainted landmarks.
Should you do that, you’ll have the ability to use these landmarks to search out these cardinal instructions within the weeks and months forward. Plus, you’ll know these instructions lengthy after Earth has moved on in its orbit across the sun.
The historical past of the seasons
Our ancestors could not have understood the equinoxes and solstices as occasions that happen throughout Earth’s yearly orbit across the sun. But when they had been observant – and a few had been very observant certainly – they absolutely marked the day of the equinox as being halfway between the sun’s lowest path throughout the sky in winter and highest path throughout the sky in summer time.
Now we are able to say with moderately excessive accuracy that the sun rises due east and units due west on the day of the equinox. And this is similar for everybody across the globe.
In case you are looking for extra precision for the dawn/sundown course in your a part of the world, take a look at the altitude/azimuth for the sun by way of timeanddate.com.
Backside line: The 2023 March equinox happens on March 20 at 21:24 UTC (4:24 p.m. CDT). On the equinox, the sun rises and units due east and due west.
A Chinese perspective on the spring equinox
