The date a year begins and ends is not based on science – it is, in the final analysis, an ‘invented’ system.
Gifts, waves, grapes, resolutions, sympathy … The midnight of 31 December is usually a moment of hope and balance for millions of people across the planet.
One year “ends” and the other “begins” and, with it, aspirations for better days and countless objectives and new goals.
It is the last day of the Gregorian calendar, the traditional 365 days (plus in the leap year 2020), which has controlled the West since the Julian calendar was no longer used in 1582.
The turn commemorates the end of a cycle that has marked the time of many cultures for millennia: the complete return of the Earth around its star.
In astronomy and many cultures, we understand both traditionally every year, this is the time when our planet takes time to revolve around the Sun. “National Astronomical Observatory of the National Astronomical Observatory.
However, as the theoretical physicist also reports, the time a year begins and ends is not based on science – it is, in fact, a convention, namely, a system, in the final analysis, “invention.” ” is.
“Starting with the assumption that the year ends at midnight on 31 December and begins on 1 January is a social construction, a definition that was created at a moment in history,” he says.
According to Larnaga, given that the basis for measuring a year is the time it takes for the Earth to move around the Sun, when this cycle begins and ends at any time, counting occurs.
“From an astronomical point of view, nothing special happens on 31 December to say that this is where the year ends, nor is there anything special on 1 January to say when it begins ,” they tell.
“In fact, there is nothing special or unusual in all the Earth’s orbit to mark the change of one year.”
But it does not stop there.
The exact length (or 366 in terms of leaps and bounds) of 365 days of the year is another social convention.
“In fact, there are many ways to measure the duration of a year,” Larnaga says.
And, depending on the form used, the duration is not the same.
But how is this possible?
Year length
Since it was introduced by Emperor Julius Caesar in 46 BCE, the Julian calendar has served to tell the passage of years and the history of Europe until the end of the 16th century.
However, since the Middle Ages, many astronomers have realized that this method of measuring time produced an accumulated error of about 11 minutes and 14 seconds each year.
It was then that, in 1582, Pope Gregory 13 promoted the reform of the calendar we use today, and introduced leap years to correct misconciliation in the Julian calendar.
There are at least four ways to count the time it takes for the Earth to move around the Sun.
Image: Getty Image
Larnaga explains that, from the point of view of astronomy, it is the basis for defining what a year is, not a single unit of measurement, but to calculate the time it takes for the Earth to move around the Sun. Low four:
– Julian Year or Calendar: “It is a convention and is used in astronomy as a unit of measurement in which the Earth is supposed to go around the Sun in 365.25 days”.
– Siderial Year: “This is the time it takes for the Earth to move around the Sun in relation to a certain reference system. In this case, a set of stars is used as a reference, and the period of this year is 365.25636 Day. “.
– Tropic Year: “It takes into account the longitude of the Sun’s eclipse, that is, the angle of the Sun in the sky with respect to the Earth during the year, mainly in the equinox. And it remains slightly lower than the constellation year, 365.242189 day. “.
– Anomaly Year: “Earth, like other planets, moves in an ellipse. This causes the ellipse, on some occasions, to be closer and more distant than the Earth. But there is a point where both are the highest. Possible. As close, the perihelion is called “. And the anomaly year is the time between the two successive paths of the Earth through its periphery. It lasts 365.2596 days.”
Although the larynga indicates that all are on the order of 365 days, assuming that the exact duration of the one-year period is a simplification.
But it also does not take any other factors into consideration.
“There is another question. That is, although we have these calculations, not the same time remains every year, there is not the same period every time,” he says.
external influences
According to the expert, although astronomers have tried to accurately calculate the time it takes to orbit the Sun for centuries, there is a fundamental problem that prevents them from obtaining a certain number.
“You have to keep in mind that the period of years is never the same as everything in the solar system changes. Take the anomaly year: As the Earth revolves around the Sun, the perihelion changes as a result of the gravitational action of other planets. Goes, like Jupiter, ”he explains.
The gravitational effect of the planets and the speed of the Earth does not always make the length of the year the same
Image: Getty Image
Theoretical physicist recalls that something similar happens with the so-called Tropic Year, which measures the time interval between or between two successive passes of the Sun by an Aries point or spring equinox.
“The tropic year also changes, because it depends on the axis of the Earth, which is twisted. It’s like a peak that is swinging. So the date and time of the equinox are also different”, he says.
“And if we compare how long the siderile year lasts in 2020, how long it lasts in 1300, we will notice a difference. It will always be about 365 days, but it will not be exactly the same period, Because the speed of the Earth is not always the same. “
