The longest night is coming…

The night from December 21 to 22 will be the longest in 2022. It is during this time that the winter solstice will take place, the moment when the center of the sun’s disk will move farthest south from the celestial equator. It will happen shortly before midnight, to be more precise — at 23:48 Kyiv time.

Actually, the duration of the previous and the following nights will differ from the longest one by less than a minute, and the inclination of the center of the Sun — by 5 arcseconds. This is not such a small value, easily measured with modern devices. It was more difficult for our ancestors, who observed the celestial phenomena with the naked eye and built huge megalithic observatories for more accurate registration of the moment of the solstice. Although in fact this moment can be most accurately determined by measuring the direct ascent of our luminary. According to modern ideas, the winter solstice occurs when it reaches exactly 18 hours and marks the beginning of astronomical winter.
On the day of the winter solstice, the maximum height of the Sun above the horizon is the smallest, and its visible path from sunrise to sunset is the shortest

On this day, at noon in the northernmost point of Ukraine, the Sun culminates at an altitude of 14°11′, and atmospheric refraction “adds” another four minutes to this value. At the southernmost point — on the Crimean Cape Sarych — the maximum height of our luminary’s ascent will be 20°10′ (plus another 3′ of “refraction”). The higher the Sun rises above the horizon, the longer its visible path, and the longer the daylight will be. For the two specified points, it will last 7 hours 44 minutes and 8 hours 50 minutes, respectively. The difference is more than an hour. In our case, this is very important, for it is one of principal reasons why the south of our country is almost in the subtropical zone, and the north has a distinct temperate-continental climate.

Having passed the southernmost point of the ecliptic, the Sun will gradually begin to approach the celestial equator and will rise ever higher every day above the horizon in the Northern Hemisphere. In order for it to culminate in the north of Ukraine at the same height at which it culminates on the day of the winter solstice at its southernmost point, it must rise 6° along an inclination. It will happen as soon as on January 31 next year, that is, more than in a month — and only a month before the start of the calendar spring. December 21, 2022 also marked the end of the three hundredth day since the beginning of the invasion of Ukraine by the occupational army of the Russian Federation. So in the longest night, let us make a wish that now the occupier retreats from our lands as relentlessly as the darkness retreats before the light after the winter solstice.