If there is one aspect that characterizes life on Earth, it is that we are full of rhythms. We are governed by the constant to-and-fro of cycles that culminate and begin again in an everlasting loop. From the smallest cycle that is day and night, to the Chandler wobble that takes more than 25 thousand years to complete a cycle. We have another period that also governs us, which we call a year, it goes through different transitions thanks to the speed at which the planet moves and other characteristics such as the axis of inclination. In the whole year, there is a day that differs from the others for having the greatest darkness since it is the shortest of all, and that of 2021 is close to arriving.
When will be the shortest day of the year 2021?
The shortest day of the year 2021 in the northern hemisphere will occur on December 21 during the winter solstice. On this date we will have the least amount of sunlight, which will only shine for a few 9 hours and 17 minutes in the center of America. Consequently, the rest of the hours will be governed by the darkness of the longest night of the whole year.
In the case of southern hemispherethis already had its shortest day that occurred on June 21 during the entry of winter for that region. But on the contrary, they will have the greatest amount of light during December, which marks the arrival of winter.
Why is there a shortest day of the year?
To understand what happens inside our biological bubble, we must first look beyond the obvious. That is to say, if you want to understand the origin of the phenomena that are projected on the planet, you must first broaden the panorama towards how the Earth is placed in the Solar System. In this way, we will find clues that guide us towards a strong explanation.
We know that over the course of a year the weather conditions change according to geolocation, but also to the seasons of the year. Spring, summer, autumn and winter govern us with their qualities and if you are an observant lover of your surroundings, you will have noticed that the length of days is not the same at all times. While the days of spring and summer tend to be brighter and longer, those of autumn and winter are distinguished by their darkness.
Precisely at the beginning of winter the shortest day of the whole year occurs, sunlight only lasts a few hours and then the longest night falls over the horizon. This is due to the movement of the Earth that is responsible for giving us the seasons of the year, called Precession of the Equinoxes.
Precession of the Equinoxes
The Earth does not rotate completely perpendicular to the imaginary horizontal plane of the Solar System, called the Ecliptic. Rather, it has a tilt angle of 23.5°. Consequently, Sunlight does not reach the entire land surface on the day side of the Earth in the same way.. There are times when the northern hemisphere is closer to the Sun and receives more heat and light. But there are also times when the southern hemisphere is inclined towards the Major Astro and the rays fall more in that region.
Thanks to this phenomenon, we have equinoxes and solstices that mark the beginning of the seasons. But it is also the explanation of why when winter enters the northern hemisphere, the southern hemisphere, on the contrary, receives summer. And it is precisely during the winter solstice when the shortest day of the whole year occurs. In December for the northern hemisphere and in June for the southern hemisphere.
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