This afternoon, December 21, at about 6 p.m. Cyprus time, the Sun will be at the winter solstice, so this winter will typically begin.
Tonight (21/12) will be the longest of the year, lasting about 14.5 hours, according to Dionysis Simopoulos, honorary director of the Eugenideion Planetarium. In fact, it will coincide with the peak of the last rain of the year, the Arctic.
Etymologically, according to the National Observatory of Athens, “solstice” comes from the words “sun” and “I stand” or “stop”. Near the winter solstice (a few days before or after), the Sun seems to be slowing down its apparent movement to the south. On the day of the solstice, this motion is zeroed and then reversed.
During the winter solstice the Sun reaches its lowest point at sunrise and then we spend the longest night of the year. The equinoxes are the days of the year where the length of the day is equal to the length of the night. Two equinoxes occur each year.
The phenomena of the equinoxes and solstices occur on all the planets of each solar system, whose axis of rotation is inclined with respect to the plane of rotation around their star. Solstices and equinoxes occur because not all days of the year are equal in length.
In summer, the days are longer and the nights shorter, while the opposite happens in winter, when the days are shorter and the nights longer. This is because, as our Earth orbits the Sun, its axis of rotation is inclined to the plane of orbit, about 23-26 ° degrees, and this plane is called the ecliptic.
As a result of the inclination of the axis of rotation in half a year (from the spring to the autumnal equinox – March 20 to September 22), the northern hemisphere “tilts” towards the Sun, with the maximum being observed around June 21, at the summer solstice. , while in the other half of the year the southern hemisphere is the one that “leans” more towards the Sun, with the maximum around December 21, at the winter solstice. The solstices and the equinoxes essentially determine the length of the seasons of the year.
According to Mr. Simopoulos, the winter solstice today is between the 20th and the 23rd of December, although the last time it happened on the 23rd of December. was 1903 and the next will be 2303. Even rarer is December 20th, with the next occurring in 2080. These variations are due to the Gregorian Calendar, which each year has 365 days, except for the leap years which have 366.
The ancient peoples especially celebrated the days of the winter solstice. This tradition was continued by the Greeks with Saturns and the Romans with Saturnalia from December 18 to 24 and the central celebration of December 25, the “Day of the Birth of the Invincible Sun”, when the fact was celebrated that the Sun was beginning to rise again. in heaven and let the days grow.
The first Christians, who were outlawed in Rome and could not meet or attend church together, held meetings secretly in their catacombs. They thus decided to celebrate Christmas on December 25, when the Romans were busy with their own feasts of Saturnalia.
But why does the winter solstice not occur today on December 25, as in the time of Christ, but on December 21? The problem, according to Mr. Simopoulos, begins with the Julian Calendar introduced by Julius Caesar in 44 BC, which had its own imperfections, because it lost one day every 128 years. The Julian calendar had established the winter solstice on December 25, but over the years, the added small error had shifted the actual date of the winter solstice.
Thus, 325 AD, the year that The Council of Nicaea took place, the winter solstice was postponed and it happened on December 22nd. However, the transfer of the winter solstice continued without correction until the year 1582, when the winter solstice occurred on December 12. Then, Pope Gregory XIII introduced a new reform, which is why the new calendar, the one we use today, is called Gregorian, and loses only one day in 4,000 years.
The Gregorian reform shook its place calendar forward based on the year of the Council of Nicaea and not the year of introduction of the Julian calendar, 44 BC. That's why the winter solstice happens today, on December 21.