In the northern hemisphere, the longest day - it is called the summer solstice - falls on June 21. 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 for almost 19 hours out of 24.
The solar system is quite complicated. The Earth’s orbit relative to the Sun is not an ideal circle, it has an elliptical shape, so at different times the Sun is a little further or a little closer to it from the Earth. The difference is insignificant - 5 million kilometers, but it is she, as well as the inclination of the earth's axis, that determine the daily and annual cycles. On the longest day - the summer solstice - Earth is 152 million kilometers from its star. On this day, the Sun is located at the highest point of the earth's non-blocking horizon - the ecliptic. Starting from June 21, daylight hours will begin to decrease slightly, until December 21 reaches its minimum, and then everything will start again.
In the culture of many nations, the longest day is still a holiday that has come from the depths of centuries. The ancient Slavs, Finns, Swedes, Balts, 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 night walks, the girls are supposed to collect 7 different colors and put them under the pillow so that the narrowed one dreams. 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 7. The Slavs also considered this day mystical and thought that it was on the night of July 7-8 that a fern blooms, which may indicate the place where the treasure is hidden. In China, there is also a similar holiday - Shyaji. In Latvia, this holiday is called Ligo and, in general, is a day off. In cities, processions and
festivities that end only with the first rays of the sun.
One of the most famous buildings, with which the longest day of the year is still associated, is Stonehenge, which ascended about 5, 000 years ago. Every year, thousands of British and tourists gather there and celebrate the beginning of summer, because from the point of view of astronomy this is precisely its beginning.
Besides the solstices, there is the equinox. These days, daylight and night 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 polar, while the rest of the six months behind the polar circle night reigns. This phenomenon can be observed in both hemispheres.
It would seem how important is 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 trifles 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 just turn on a table lamp or a chandelier. But still, people like summer and sunny days more than winter and cloudy skies.
