The March 2022 equinox is close to making its triumphant entrance when the Sun hits the equator, causing both day and night to have the same duration. But also, it will mark the entrance of astronomical spring in the northern hemisphere and autumn in the southern hemisphere. To better understand this astronomical phenomenon, we have listed a series of important keys that you should know about the March 2022 equinox.
What are the equinoxes?
The equinox, like the solstice, are two astronomical phenomena that derive from the movements of the Earth, specifically from the Precession of the Equinoxes and Nutation. Both mark the entrance of the different seasons of the year and therefore bring us changes in the weather seasons.
The name equinox comes from the Latin term ‘aequinoctium’ which means ‘equal night’. The March equinox marks the beginning of spring and/or autumn, depending on the geographic pole. In this, the Sun hits the Earth exactly on the equator line, which means that both the South Pole and the North Pole are at the same distance from the Sun, causing both hemispheres to receive the same amount of light. That is why the equinoxes are of the utmost importance, because on that date the duration of the day and night will be practically the same.
Changes in the length of days
To understand how the equinoxes work, we must remember that our Earth does not rotate perfectly perpendicular to the ecliptic, but rather has an angle of inclination of 23.5º. This factor together with all the movements of the planet that are not only two, but at least five (rotation, translation, precession of the equinoxes, nutation and Chandler wobble), result in the planet rotating more or less as it is done by a spinning top or spinning top.
In this sense, there will be times when the Earth tilts towards the Sun, causing most of the light to fall on the northern hemisphere. And conversely, there will be times when it leans against the Sun, when the southern hemisphere will receive a greater amount of light. But there will also be times when the light falls squarely on the equator and precisely at these moments are known as equinoxes.
This is why they mark the beginning of the seasons of the year, because from that moment light or shadows will begin to reign depending on whether it is a spring or autumn equinox. This also explains why the equinoxes of both hemispheres are opposite, because while one of them receives the greatest amount of light, the opposite hemisphere receives shadows.
With this they also bring changes in the duration of the day and night, which does not occur abruptly, but rather gradually. For this reason, when a spring equinox occurs, day and night have the same duration, because the Sun hits the equator. However, from here on, it will begin to affect more and more the hemisphere where it marks the beginning of spring and the length of the days will begin to extend. Otherwise the opposite hemisphere, which will begin to experience shorter days and longer nights.
March equinox 2022
This year the March equinox will occur on the 20th of the month at exactly 15:24 UTC when spring begins in the northern hemisphere and autumn in the southern hemisphere. At this precise moment, darkness and light will reach equilibrium, and both in the north and in the south, day and night will have exactly the same duration.
However, from this moment on, an extraordinary phenomenon will occur where, thanks to the inclination axis of the planet, the northern hemisphere will begin to receive more light, lengthening its days. Contrary to the southern hemisphere, which little by little will receive less sunlight, shortening its days.
It might interest you