In the northern hemisphere, the longest day - it's called the summer solstice - falls on June 21st. On this day, the sun is in the sky for 17.5 hours, if we take the Moscow latitude. In St. Petersburg, daylight hours last almost 19 hours out of 24.
The solar system is quite complex. The orbit of the Earth relative to the Sun is not a perfect circle, it has an elliptical shape, so at different times the Sun is a little further or a little closer to the Earth. The difference is insignificant - 5 million kilometers, but it is she, as well as the tilt of the earth's axis, that determine the daily and annual cycle. On the longest day, the summer solstice, the Earth is 152 million kilometers from its star. On this day, the Sun is located at the highest point of the earth's sky - the ecliptic. Beginning on June 21st, the daylight hours will begin to gradually decrease until December 21st reaches its minimum, at which point everything starts all over again.
In the culture of many nations, the longest day is still a holiday that came from ancient times. ancientSlavs, Finns, Swedes, B alts, Germans and Portuguese celebrated, and in some places still continue to celebrate this day as the beginning or middle of summer. For example, in Sweden on the summer solstice
after a night of festivities, girls are supposed to collect 7 different flowers and put them under the pillow so that they dream of their betrothed. The Celts on this day celebrated Lita - the middle of summer. This holiday was directly related to the pagan cult of the sun.
In Russia, the analogue of these holidays was the day of Ivan Kupala, which is celebrated a little later - July 7th. The Slavs also considered this day mystical and thought that it was on the night of July 7-8 that the fern blooms, which may indicate the place where the treasure is hidden. In China, there is also a similar holiday - Xiazhi. In Latvia, this holiday is called Ligo and, in general, is a day off. Processions are held in the cities and
folk festivals that end only with the first rays of the sun.
One of the most famous buildings, which is still associated with the longest day of the year, is Stonehenge, starred about 5000 years ago. Every year, thousands of Britons and tourists gather there and celebrate the beginning of summer, because in terms of astronomy, this is precisely its beginning.
Besides the solstices, there is also the equinox. On these days, daylight hours and nights take an equal amount of time, and such moments occur 2 times a year: March 21-22 and September 22-23.
If you set out to find out how long the longest day really lasts, then the answer will be simple - six months. And this day is called the polar day, while the rest of the six months beyond the Arctic Circle reigns night. This phenomenon can be observed in both hemispheres.
It would seem, what is the importance - the longest day in the northern hemisphere. Why celebrate such a day, and indeed, with the invention of electricity, a person almost ceased to depend on such a trifle as the presence of the sun in the sky. However, in reality, everything is much more complicated. Of course, now after sunset it is not necessary to go to bed, but you can simply turn on a table lamp or chandelier. But still, people love summer and sunny days more than winter and cloudy skies.
