Spring will start in a few days … How was the date set? At what time will the astronomical event of the equinox occur and how to explain it?
The spring equinox will officially start Thursday March 20, 2023 at 10 a.m. and 30 seconds according to theInstitute of celestial mechanics and calculation of ephemeris Located in the Paris Observatory. During the spring equinox, the sun crosses the equator from the southern hemisphere to the northern hemisphere, thus marking the beginning of spring in the northern hemisphere and autumn in the southern hemisphere. The spring equinox marks the beginning of softer temperatures, the greening of trees and longer days in the northern hemisphere and, conversely, the start of low temperatures in the southern hemisphere.
At this precise moment, the duration of the day is equal to that of the night, but it is no longer the same as the summer approach with shorter nights and longer sunshine durations. Remember that in average, during the spring, we win in France and in the temperate regions 4 minutes of sun every day! Enter behind the scenes of the equinox by sailing in our special page thanks to the summary above.
How is the date of spring set?
From an astronomical point of view, spring begins at the time of the Vernal equinox, which can take place between March 19 and 21. It lasts until summer solstice. This means that spring lasts about three months. The date of the equinox is calculated for each year by astronomers and mathematicians. It is a question of providing the exact moment when the plan of the equator and that of the trajectory of the earth coincide. A calculation made necessary by the discrepancy between our calendar, our hourly system and the movements of the stars. First, the orbit of the earth is not perfectly circular, which depend on its position on this orbit, the earth can be more or less close to the sun (between 147 million kilometers minimum and 152 million kilometers maximum). This inevitably makes the durations of each season very irregular and therefore the Variable spring date.
Other explanation: The earth does not take exactly 365 days to go around the sun. In this our Gregorian calendar, established in the 16th century, is far too simplistic. It takes 365.2422 days very exactly (365 days, 5 hours and 46 minutes) so that we have done the full tower of the star! We are therefore forced to add from time to time on February 29 (during bissextile years) to correctly correct (and partly only) this discrepancy. A punctual addition which artificially repels the date of spring of one day during the bissextile years. This explains why astronomers “advanced” on March 20 last year. And that the situation presents itself again this year.
During the establishment of the Julien calendar by César, in 45 BCE, the spring equinox had been set for March 25, according to the imprecise observations of the time. But the absence of February 29 in this ancient calendar ended up moving this date until March 11 in the 16th century … It was only during the establishment of the Gregorian calendar (the one we use today), in 1582, that an approaching date of March 21 was chosen.
The date of “common” spring should not be confused with that of meteorological springwhich begins every year on March 1, allowing meteorologists to do their seasonal calculations on a whole month. In meteorology, we consider that spring begins on March 1 to end on May 31: in this discipline, we characterize spring as a period of warming temperatures (under our latitudes) and increased duration of the day. It is also one of the most difficult seasons to analyze in this discipline. However, it is the equinox that continues to mark the advent of spring in the minds of people.
What is the definition of the spring equinox?
The word equinox comes from the Latin “æquinoctium” (“equal night”) Because the most visible phenomenon for humans is that the duration of the day becomes identical to that of the night. The reason for this phenomenon? The equinox corresponds to the time of the year when the sun crosses the equatorial plane of the earth. The star is then at the Zenith of Ecuador, which allows day and night to share time in equal parts. And this in the two hemispheres, south and north. On our side, the days extend and we are halfway between the short days in December and the long days in June. During the equinox, the axis of rotation of the earth on itself and the axis of rotation of the earth around the sun therefore correspond exactly. On our planet, during the equinox, our star appears to the east to the dawn to disappear battery to the west.
This phenomenon is also linked to geometry. The axis of rotation of the earth is naturally inclined by 23.4 ° compared to the plan of its orbit. In other words, Our planet “leans” in relation to the plan on which it revolves around the sun (see diagram below). The star therefore lights it up differently depending on the moments of the year. This phenomenon explains why the days extend or shorten between summer andwinter. This also gives birth to the seasons, due to the warming or cooling of the air masses and the oceans according to the time spent every day under the shelves of the star. The distance between the sun and the earth, on the other hand, has no direct link with the temperature. Know for example that the earth reaches the point closest to the sun (the perihelion) on January 3, that is to say in the heart of our winter.
Spring equinox: what does the image phenomenon look like?
The equinox takes place twice a year: between March 19 and March 21 (spring or vernal equinox) and between September 22 and 23 (autumn equinox). In the spring the duration of sunshine increases at the equinox to reach 4 p.m. at the end of June, during the summer solstice. Conversely, the autumn equinox begins a period of reduction of the day which descends barely more than 8 hours at winter solsticearound December 21. During the equinox on the other hand, no jealous: day and night are supposed to last 12 hours each. These data nevertheless vary slightly since the shape of the earth is not perfectly regular and the atmosphere slightly diverts the rays from the sun. Thus, in Paris, on March 20, last year the sun rose at 6:52 am to go to bed at 7:03 pm. The duration of the day was therefore very slightly greater than 12 hours. It is also at the time of equinoxes that the duration of the day increases/decreases the fastest in our latitudes.
What is the pagan party of the spring equinox?
Spring Equinoxes and pagan party are closely linked. Thus, various celebrations of the spring equinox around March 21 existed in very ancient times, some of which are still surviving today. Among them, the lights of joy that symbolize the release of the darkness of winter; or the cakes offered to a deity; When it is not a straw mannequin that you burn or put in the water, as if to “destroy” winter.