El spring equinox or March equinox is the day that marks the starting point of the beginning of spring in the terrestrial northern hemisphere and autumn in the southern hemisphere.
The spring equinox, like other astronomical ephemeris such as the solstices, is a remarkable event. Although in different cultures this day has been used to mark the beginning of a new season, today it helps us put into perspective the way in which our civilization has dedicated itself to studying the stars.
In fact, the vernal equinox is a fraction of 4 events that mark the changes of the seasons in the northern and southern hemispheres of the planet: vernal equinox, autumnal equinox, summer solstice and winter winter solstice.
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The study of phenomena such as the equinoxes are perfect for understanding the behavior of our planet as a result of its own movement and its orbit around the Sun.
For this reason, in this interesting article we will study in detail the most important elements of the spring equinox and other similar events: What causes them? What effects do they have on our daily lives? And when is the spring equinox?
We start with the first, do you know what an equinox is?
What is an equinox?
The word equinox is used to define the day of each year that the sun is in a completely parallel position in reference to the projection of the terrestrial equatorial line.
It comes from the Latin term aequinoctium, which means "equal night". This is because, during the equinoxes, when the sun is at the zenith of the sky, night and day will have practically the same duration anywhere on the planet.
On this day, if the sun is observed from a point close to the equator, it will be positioned on the ecliptic just 90° above the observers' heads. As a curious fact, during a fraction of the day, the mass will not cast shadows on Earth.
Our planet experiences two equinoxes each damage. The first (March equinox), occurs between March 19 and 21 and the second (September equinox), occurs between September 21 and 24.
For example, him spring equinox 2019 occurred on March 20 and the spring equinox 2020 occurred on March 19.
Historically, the equinoxes have been used by different generations to mark the beginning of the seasons (spring and autumn, depending on the terrestrial hemisphere).
Now, what is the spring equinox?
As its name indicates and according to the explanation given previously, the spring equinox is the day of the year that marks the beginning of the spring season in the northern hemisphere of the Earth.
This event occurs every year during the month of March when the Sun is located in the first point of aries or first point of libra with reference to the projection of the celestial equator.
Casting light evenly across the planet, the March equinox, like the September equinox, are the only times of the year when the length of the day is similar across the planet.
Despite this, there are certain variations with the duration of sunlight, especially in regions near the Earth's poles.
As a curious fact, at the North Pole of the Earth, the spring equinox marks the moment in which a day will begin that will last for approximately 6 months, since the inclination of the terrestrial plane will show the north face to the sun during half of the translation. . In contrast, the South Pole will experience a 6 month long night.
Why do equinoxes occur?
The equinoxes, like the summer and winter solstices, they occur due to the slight tilt of the Earth's axis of rotation with reference to the plane of translation around the Sun, that is, our planet rotates slightly tilted to one side.
This means that the sun's rays do not hit all areas of the face of the planet equally during the day, causing one hemisphere to be "closer to the sun" than the other for some months of the year (this is the phenomenon that causes the seasons).
Well, during its movement through the plane of the terrestrial ecliptic, which is the imaginary line through which the sun appears to travel on our horizon, the star manages to align with the terrestrial equator only twice a year.
These two days in which the sun is located in parallel with the equatorial projection, the sun's rays hit the Earth evenly, making the days have the same length in both hemispheres of the Earth.
Why can the equinoxes occur on different dates?
As we have described, none of the equinoxes occur on the same day each year, but within a tight range of dates, but why is this?
You see, the length of the world standard calendar (the Gregorian calendar) does not accurately express the time it takes for our planet to complete one orbit around the sun (solar year).
In fact, under our calendar, a solar year takes exactly 365 days and an additional six hours. This gap is the reason why some astronomical events can occur on different dates each year.
For the same reason, leap years have been included in our calendar. Every 4 years an additional 24 hours are added (on February 29) to compensate for the time difference in the Gregorian calendar and restart the cycle.
Spring equinox for some cultures
Astronomical events such as the spring equinox were extremely important ephemeris for cultures around the world, especially for those who had developed a love for the study of the stars.
This day was calculated exactly and they took advantage of it for celebrations or rites closely linked to the identity of their culture.
Spring Equinox at Chichen Itza
It is known that the Mayans were expert cosmologists at the time and many of their constructions were designed to pay tribute to the stars and cosmic events.
In fact, the spring equinox was a sacred day for them, marked by the arrival of the God Kukulkan in the form of a serpent of light that descended from the sky to announce the beginning of spring.
One of the most impressive expressions of this Mayan tradition is found in the Temple of Kukulkan in Chichen Itza, which is designed to directly receive the solar rays of the spring equinox, projecting perfect triangles of light along its 91 steps.
Spring Equinox in Japan
Buddhist culture has celebrated the March equinox for centuries with a festival called Shunbun No Hi. For Buddhists, the influence of the sun's direct impact on our planet symbolizes the change in people's spiritual state, from suffering to enlightenment.
Today it is a public holiday throughout Japan and is traditionally used by citizens to mark the beginning of important changes in daily life: having children, changing jobs, paying tribute to deceased relatives, moving to another city, etc.
Spring Equinox for the Greeks
The Greeks were the ancient civilization that probably achieved the most outstanding advances in astronomical observation and study, so it is not surprising that these types of events have been so closely linked to their culture and religious beliefs.
The spring equinox in Greece marks the end of the winter cold and marks the beginning of spring, the time when flowers and vegetation in general are reborn, it is also the ideal time to start with the new harvests of the year.
Perhaps for this reason, in Greek mythology, this date marks the moment when Persephone (goddess of spring, flowers and fertility) escaped her kidnapping in the underworld to reunite with her mother Demeter (goddess of agriculture) .