White Nights have long been a visiting card and one of the main attractions of St. Petersburg. This unusual natural optical phenomenon is observed in the city on the Neva every year from June 11 to July 2. At this time, the center of the solar disk falls at midnight below the horizon by no more than seven degrees, which leads to a fairly high level of illumination for this time of day.
The geography of this unusual natural effect is quite extensive. White nights are observed at the beginning of the summer period in both hemispheres at latitudes exceeding sixty degrees. But in our minds, they have long become a symbol of St. Petersburg. At this time, the city does not seem to sleep, watching the magical studies of nature. Many concerts, festivals and performances are held here. It seems that the whole city is immersed in the magic of natural effects. At this time, a huge number of tourists come here, as well as music and film stars from all over the world.
Every year in northern Palmyra in June, a rock festival with a very symbolic name "White Nights in St. Petersburg" takes place. Also at this time, an international film competition is held here, where films shot during the year are shown. Days of white nights in the largest non-capital city in Europe are marked by an extremely rich and intense cultural life. This is a magical holiday, given by nature itself, which is also one of the tourist attractions of the city on the Neva. St. Isaac's Cathedral on a white night looks especially impressive.
What is this phenomenon from an astronomical point of view and what is the mechanism of its formation? The term "white nights" is used to designate a qualitative characteristic of twilight, which is characterized by a fairly high level of natural light. In fact, during the period approaching the summer solstice in the Northern Hemisphere, evening twilight merges with morning. The process of movement of our planet in its orbit is associated with a change in the angle of inclination of the earth's axis by a certain number of degrees. As a result, the North Pole moves to the point of perihelion, which is accompanied by an almost perpendicular incidence of sunlight on the surface of the planet in the polar regions. This causes such unusual optical effects that have come into use under the name "white nights".
Such a natural phenomenon in Russia is typical not only for St. Petersburg, but also for Murmansk, Norilsk, Vorkuta, Cherepovets, Vologda, Magadan,Nizhnevartovsk, Khanty-Mansiysk, Nefteyugansk, Surgut, Yakutsk, Arkhangelsk and many other cities and regions located north of the sixtieth parallel. In addition, such an effect was observed in latitudes closer to the equator, which was caused by the fall of the Tunguska meteorite. After that, various optical anomalies could be observed on the territory of many European countries and in Russia, including the so-called bright dawns and white nights, which are completely uncharacteristic for these regions.
Outside of Russia, this phenomenon is also not so rare. Finland, for example, is generally considered the land of white nights. Also, this natural optical effect is characteristic of northern Sweden, Iceland, Norway, the polar regions of Canada, Greenland and even Estonia. In the UK, white nights can be seen in the Orkney Islands.
