Declining day in summer. Daylight hours have increased by a "chicken's pace"

Instructions

The length of the day depends on the daily rotation of the Earth around its axis and the orbital rotation around the Sun. Due to the Earth's orbit, the solar disk makes an annual visible circuit celestial sphere, moving along the ecliptic. In this regard, it changes and affects the length of the day differently at different geographic latitudes.

At the earth's equator daylight hours approximately constant and lasts about 12 hours. In the northern hemisphere of the Earth, from March to September there are more than 12 hours of daylight, and from the end of September to the end of March - less. IN Southern Hemisphere everything is exactly the opposite. In the Arctic Circle in summer, daylight hours can be longer than 24 hours. This phenomenon is called polar day. At the poles, the day length is six months.

The shortest and longest daylight hours occur during winter and summer solstice. In the northern hemisphere, the winter solstice falls on December 21 or 22 (depending on), and the summer solstice falls on June 21 or 22 (in a leap year it can occur on June 20). On the other side of the equator - in the Southern Hemisphere - the December solstice occurs in summer, and the June solstice in winter.

During winter solstice The length of daylight hours is only 5 hours 53 minutes. - This is the shortest day of the year and, accordingly, the longest night. The summer solstice makes it possible to live the longest day - 17 hours 33 minutes. Having reached its maximum duration, from that moment the daylight hours begin to decrease until the winter solstice arrives again, and it begins to increase again.

For a long time, the traditions of many peoples have preserved the custom of celebrating the winter and summer solstice. So, in Russia, for example, short day Every year there is a holiday called “Kolyada”.

Historians claim that the ancient Egyptians knew about the solstice. There is a version that they built the majestic pyramids in such a way that on the day of the summer solstice the sun would set between them. You can verify this phenomenon by looking at the pyramids from the Sphinx.

The famous British Stonehenge, located 130 km from London, also conceals many mysteries and secrets. Some scientists call it an ancient observatory and also associate it with the summer solstice. Because it is on this day that the Sun rises above the Hillstone stone, located somewhat separately from the main structure.

Sources:

What number is missing 9,6,3, in order of decreasing to 10

There are places on Earth where the length of daylight is the same all year round- These are the areas lying on the equator. In all other areas of the planet, day length varies from a maximum of day summer solstice (June 22) to a minimum at day winter solstice (December 22). The closer the area is to the equator, the weaker these fluctuations are, and vice versa.

The Earth's axis is inclined to the ecliptic, that is, to the plane in which the Sun-Earth system is located, at an angle of approximately 66.6 degrees. If it were not for this tilt, the length of daylight at any point on Earth would be the same all year round, determined only by the geographic latitude of the area. But it is precisely because of this axis tilt that the Northern Hemisphere faces the Sun for most of the day during the period between the spring and autumn equinox (from March 21 to September 22). The southern hemisphere, accordingly, faces the Sun for less of the day. Therefore, during the period when it is summer in the North, it is winter in the South. Well, when the Earth, having described a semicircle around the Sun, moves to the opposite point of its orbit, everything changes. Now the Southern Hemisphere faces the Sun most of the day, so it is summer there, and winter in the Northern Hemisphere. Accordingly, the length of the day in the Northern Hemisphere is sharply reduced. On the territory of Russia, as well as in the entire Northern Hemisphere, the shortest winter season day– 22. There are vast areas where polar nights occur, meaning the sun does not rise above the horizon at all. This is observed in places located north of the so-called Arctic Circle, that is, geographical, approximately equal to 66.5 degrees. The duration of the polar night ranges from several days to several months (in areas close to North Pole). After the winter day, the duration of daylight hours steadily increases. At first, this increase is almost imperceptible, since it is only a few minutes per day. But gradually the light day becomes significant. And in day spring equinox(March 21), considered the beginning of astronomical spring, its duration is compared to the length of the night.

Video on the topic

The signs are based on real observations of people. Signs are conclusions from observations of events that occur every year. In the same way, signs regarding the leap year were born.

What caused the signs?

From the point of view of astrology, these signs are quite justified, because a leap year is the beginning of a four-year cycle, and if you approach an undertaking without due responsibility, then the undertaking is likely to fail, bringing with it serious troubles.

The signs are also justified from a religious point of view. Leap year is the only year when there is, and this number is associated with Kasyan, who serves evil spirits and harms people.

What signs are there

It is not recommended to change anything in your life during a leap year, since all changes will be futile. You should not change your place of residence, place of work, type of activity, partner, etc. Some superstitious people do not even recommend changing your wardrobe and hairstyle.

According to signs, if you happen to experience a divorce during a leap year, you should buy a towel, take it to the church and give it to the women who clean there.

It is also not a good idea to get married during a leap year. There are a lot of superstitions associated with weddings that fall on a leap year. It is believed that a marriage entered into in a leap year will fall apart very quickly for one reason or another - conflicts, infidelity or the death of one of the spouses.

Planting at the beginning of the four-year cycle will not produce a large harvest. And according to another sign, if you plant something in the garden during a leap year, you can “bury” yourself or one of your relatives, i.e. to the death of a family member. Therefore, when planting something in the ground, you need to say: “I plant it in a leap year, so it will die.”

Explanation will accept

Signs are a good thing. However, you shouldn't be so superstitious. If you were offered worthwhile work, which you know you can handle, then why not accept this offer? And if you don’t calculate your strength, you can lose your job at any time.

Divorce is generally the last thing to happen in any year. If there is an opportunity to save a family, especially if there are children in it, then you need to use it. And it is not at all necessary that you will not be able to improve your personal life later. Of course, if in your new marriage you behave the same way as in your first, then there can be no talk of any happiness.

Well, the earth generally loves respect. If you plant something, then you need to talk to the earth, ask it for a good harvest. Saying a few words to the earth while planting something is not difficult, but the harvest can be bountiful.

Old people will not talk in vain. All signs are observations of more than one generation, so you should not brush them aside. But you shouldn’t believe blindly and thoughtlessly. Think logically about each sign and decide for yourself whether to believe in it or not.

Video on the topic

At the end of December 2017, namely on the 21st, exactly at 17:28 Moscow time, it was the winter solstice. This day marks the beginning of the winter solstice period, and also indicates the beginning of “astronomical winter” and a change in the zodiac constellation, that is, the Sun begins to turn towards spring. The solar disk seems to freeze in place for about three days, so the night from December 21 to 22 is the longest of the year.

After the solstice period, our luminary begins to consistently rise above the horizon, adding minutes to the daylight hours. On December 21, 2017, daylight lasted almost 7 hours, but by the end of the year 6 minutes had been added to it. Such astronomical changes are typical for northern hemisphere our planet, while in the southern hemisphere, the period of the summer solstice begins.

Astronomical science explains this phenomenon by the fact that during the winter solstice in the northern hemisphere of our planet, the sun appears above the horizon for less time. And at the moment when the sun passes through the very Southern point ecliptic - there will be an exact time of the winter solstice. The rate at which daylight increases solely depends on the angle of the Sun and the speed of rotation of the celestial body.

You can find out how much the day has increased since December 22, 2017 by ancient signs

For thousands of years, for all the peoples of our planet, the period of winter solstice has been great value. Our ancestors lived in harmony with nature and tried to organize their lives in accordance with natural cycles. Ancient people worshiped the Sun, because they understood that its light and warmth would not exist on Earth.

In Russian folk art there are many proverbs and signs associated with this day:

if you start a new business on the day of the solstice, it will be successful;
if the weather on the day of the winter solstice is good, then New Year she will be the same;
if frost is observed on this day, then the grain harvest this year will be rich;
if the weather is windy, then fruit trees will produce a good harvest;
If the weather is rainy, there will be a lot of floods at the beginning of spring.

On the day of the winter solstice, the ancient Slavs celebrated the pagan New Year, which was associated with the ancient God - Kolyada. European residents associated this day with the beginning of a new life and the renewal of nature. And the inhabitants of ancient Scotland had a tradition of throwing an unusual solar wheel, which they called “solstice.”

How many days have been added since December 22, 2017, the first mention of the winter solstice in the calendar

The inhabitants of the Celestial Empire were the first to define the winter solstice in their calendar. Totally old Chinese calendar There were 24 seasons a year.

In ancient China they believed that from this moment the male power nature and a new life cycle begins. The winter solstice was considered happy, so on this day the ancients organized various celebrations. The tradition of celebrating the winter solstice among Chinese residents has survived to this day.

IN Ancient India This day was celebrated in the Hindu and Sikh communities, and it was called Sankranti. At night, on the eve of the celebration, locals lit many bonfires. They symbolized the warmth of the heavenly body, which began to warm the earth after the end of winter frosts.

How much has the day increased since December 22, 2017, why are the clocks moved?

Nowadays, changes in daylight hours are associated with economic feasibility. Many countries move the clock hands forward or backward one hour, in certain phases of daylight hours to save electrical energy. But practice recent years shows that such external interference in natural astronomical processes leads to sad consequences.

Countries that experiment with changing clocks save only 1% of electricity, while increasing the number of injuries among the population, suicides, chronic diseases, as well as massive conflict situations. The human body constantly reacts to natural and astronomical changes and tries to adapt to them. When the clock hands are constantly moving, the usual daily routine changes and this causes disturbances in the functioning of all body systems.

Today, many states have listened to statistical data and expert opinions. They categorically refused to conduct experiments with changing clocks, which do not save energy resources in any way, but only bring harm to the health of the entire population.

Reduction in autumn-winter period the duration of daylight hours affects the deterioration of well-being and weakening of a person’s immunity, the change from the rising phase to the falling phase in all life cycles, an increase in the expenditure side of countries' budgets, the suspension of seasonal work in a number of sectors of the economy ( agriculture, construction and others).

The winter solstice marks the minimum daylight hours. On this day, the Sun crosses the farthest point of the ellipse along which the Earth rotates. This day for residents of the northern hemisphere of our planet occurs on December 21-22, while at the same time, for residents of the southern hemisphere, the summer solstice day of maximum duration begins.

Sunlight promotes the production of the hormone serotonin in the human body, evoking emotions joy and happiness. With short daylight hours, the production of serotonin is reduced, which depresses the emotional sphere of the body and leads to a deterioration in its condition. The equality of the length of day and night on the days of the autumn and spring equinoxes creates ideal conditions for daily biorhythms. The period of the cycle, beginning on the day of the autumn equinox and ending on the day of the winter solstice, represents the stage of reduction of daylight hours in the phase of its lag from the duration of the night. This stage is the most unfavorable; during it, all life on Earth is increasingly oppressed. The second stage, beginning on the day of the winter solstice and ending on the day of the spring equinox, is also in the phase of the lag between daylight and night, but this lag is gradually decreasing, negative influence lack sunlight gradually weakens. The less a person receives per day sun rays, the more he is susceptible to nervous breakdowns, even depressive states and mental disorders. Technical civilization is trying to compensate for the lack of sunlight with artificial lighting, to which the human body is not adapted; it perceives artificially illuminated night hours as daylight hours, falling into the so-called state of desynchronosis, which aggravates chronic diseases.

At the same time, the population of the northern hemisphere is less affected by the changing seasons than the population of the southern hemisphere, because In winter, the northern hemisphere is closer to the Sun. The period from sunrise to sunset is called the length of the day. This value depends on geographical latitude. At the equator, the length of the day is a constant of 12 hours. In the northern hemisphere, in the autumn-winter period, the length of the day is less than 12 hours, and in the spring-summer period, it is more than 12 hours. At the Earth's poles, polar day and night last six months. Given the importance of day length, daily and monthly average day length tables have been compiled for each latitude.

For example, the minimum average monthly day length at the latitude of Moscow is 7 hours 16 minutes in December and 7 hours 51 minutes in January.

December 21 (date indicated for 2016) is the winter solstice. Solstice is one of two days a year when the height of the sun above the horizon at noon is minimum or maximum. There are two solstices in the year - winter and summer. Solstice is one of two days a year when the height of the sun above the horizon at noon is minimum or maximum. There are two solstices in the year - winter and summer. On the day of the winter solstice, the sun rises to its lowest height above the horizon.

In the northern hemisphere, the winter solstice occurs on December 21 or 22, when the shortest day and longest night occur. The moment of the solstice shifts every year, since the length of the solar year does not coincide with calendar time.

In 2016, the winter solstice will occur on December 21 at 13.45 Moscow time

After the longest night of the year, which will last about 17 hours, real astronomical winter will begin. The Sun will descend to its maximum in the southern hemisphere of the sky, that is, moving along the ecliptic, it will reach its lowest declination. The length of the day at the latitude of Moscow will be 7 hours. The sun crosses the 18 o'clock meridian and begins to rise up the ecliptic. This means that after crossing the celestial equator, the luminary will begin its path to the spring equinox.

During the winter solstice, the sun does not rise above a latitude of 66.5 degrees at all - only twilight at these latitudes indicates that it is somewhere below the horizon. At the North Pole of the Earth, not only the Sun is not visible, but also twilight, and the location of the star can only be determined by the constellations. On December 21, the sun crosses the 18 o'clock meridian and begins to rise up the ecliptic, beginning its journey towards the spring equinox, when it crosses the celestial equator.

Winter Solstice Day among the Ancient Slavs

The winter solstice has been observed since ancient times. Thus, in Russian folklore there is a proverb dedicated to this day: the sun is for summer, winter is for frost. Now the day will gradually increase, and the night will decrease. The winter solstice was used to judge the future harvest: frost on the trees meant a rich grain harvest.

In the 16th century in Rus', the day of the winter solstice was associated interesting ritual. The bell ringer of the Moscow Cathedral, who was responsible for striking the clock, came to bow to the Tsar. He reported that from now on the sun has turned to summer, the day is increasing, and the night is shortening. For this good news, the king rewarded the headman with money.

The ancient Slavs celebrated the pagan New Year on the winter solstice; it was associated with the deity Kolyada. The main attribute of the festival was a bonfire, depicting and invoking the light of the sun, which, after the longest night of the year, was supposed to rise higher and higher. The ritual New Year's pie - loaf - was also shaped like the sun.

The day of pagan veneration of Karachun (the second name of Chernobog) falls on the day of the winter solstice (celebrated depending on the year from December 19 to 22) - the shortest day of the year and one of the coldest days of winter. It was believed that on this day the formidable Karachun, the deity of death, the underground god who rules frosts, takes his power. evil spirit. The ancient Slavs believed that he commands winter and frost and shortens the daylight hours.

The servants of the formidable Karachun are connecting rod bears in which snowstorms turn, and blizzard wolves. It was believed that, due to the bear's will, the cold winter continues: if the bear turns on the other side in its den, it means that winter has exactly half the way to go until spring. Hence the saying: “At Solstice, the bear in its den turns from one side to the other.” The people still use the concept of “karachun” in the sense of death. They say, for example: “karachun has come for him”, “wait for karachun”, “ask karachun”, “enough karachun”. On the other hand, the word “karachit” can have the following meanings - backing away, crawling, “hunched” - writhed, cramped. Perhaps Karachun was called that precisely because he seemed to force the daytime to go to reverse side, backing away, crawling, yielding to the night.

Gradually, in the popular consciousness, Karachun became close to Frost, who binds the earth with cold, as if plunging it into a mortal sleep. This is a more harmless image than the stern Karachun. Frost is simply the lord of winter cold.

Winter Solstice Day among Other Nations

In Europe, these days began a 12-day cycle of pagan festivals dedicated to the winter solstice, which marked the beginning of a new life and renewal of nature.

On the day of the winter solstice in Scotland there was a custom to launch the sun wheel - “solstice”. The barrel was coated with burning resin and sent down the street. The wheel is a symbol of the sun, the spokes of the wheel resembled rays, the rotation of the spokes during movement made the wheel alive and similar to a luminary.

The winter solstice was determined earlier than all other seasons in China (there are 24 seasons in the Chinese calendar). IN ancient China It was believed that from this time the male force of nature rises and a new cycle begins. The winter solstice was considered a happy day worthy of celebration. On this day, everyone - from the emperor to the commoner - went on vacation.

The army was put into a state of waiting for orders, border fortresses and trading shops were closed, people went to visit each other, gave each other gifts.

The Chinese made sacrifices to the God of Heaven and their ancestors, and also ate porridge of beans and glutinous rice to protect themselves from evil spirits and diseases. To this day, the winter solstice is considered one of the traditional Chinese holidays.

In India, the day of the winter solstice - Sankranti - is celebrated in Hindu and Sikh communities, where on the night before the celebration bonfires are lit, the heat of which symbolizes the warmth of the sun, which begins to warm the earth after the winter cold.

Russian folk calendar for December 21 (December 8, old style) - Anfisa Needlewoman

On this day they commemorate Saint Anfisa of Rome, who suffered for the Christian faith in the 5th century. Anfisa was the wife of a Roman dignitary and professed Christianity (according to legend, she was baptized by Saint Ambrose of Milan, whose memory is celebrated the day before). One day, the mayor's wife invited her to accept Arian baptism (Arian teaching denied the unity of God the Father and Jesus Christ). Anfisa refused and, following the woman’s slander, was burned at the stake.

After Anfisa, all girls in Rus' were supposed to do handicrafts: spinning, weaving, sewing, embroidering. It was advisable to do this alone, and if it was not possible or you did not want to be alone, special rituals against damage were performed.

A girl sews for Anfisa, but an extra eye while sewing is an evil eye, our ancestors said and advised young needlewomen to wrap a silk thread around their wrist so as not to prick their fingers with a needle. The same ritual protected against yawning and hiccups.

The embroidery itself, in which various kinds of symbols were often encrypted, also had magical powers. Thus, diamonds on towels signified fertility; round rosettes and cross-shaped figures on clothing protected its owner from misfortune. In traditional embroidery patterns there are also images of the sun, trees, and birds, personifying the vital forces of nature. Our ancestors believed in their power, believing that they would bring prosperity and prosperity to the house.

The Russian folk calendar will accept December 22 (December 9, old style) - Anna Zimnyaya. Anna Dark. Conception of Saint Anne.

The Church celebrates not only birth, but also conception. With the Feast of the Conception of Anna, winter begins: autumn ends, winter begins. The beginning of the present harsh winter. In the meantime (lace) on the trees for the Conception of Anna for the harvest. If the snow rolls right up to the fence - bad summer, and if there is a gap, it’s productive. December 22 is the shortest day of the year, the solstice day.

On the Conception of Anna, pregnant women must strictly fast (on other days, pregnant women are exempt from fasting), avoid any quarrels and troubles, and avoid being seen by the crippled and disabled; You must not light a fire, knit, embroider or take on any work, so as not to accidentally harm the unborn child. People knowledgeable in these matters claim that the fire kindled on this day can leave a red mark on the child’s body, tangled threads twist his umbilical cord, and the poor, ugly, seen by his mother, can pass on their injuries to the child. The wolves come together at Conception, and after Epiphany they scatter.

The memory of St. Anna, the parent of Mary, the future Mother of God, is celebrated twice a year: on August 7, a service is held in churches for the dormition of Anna, her death. December 22 is the day of the winter equinox, in the south of Russia it is considered the beginning of winter. A change in the weather is also noticeable: “Sun for summer, winter for frost.” On this morning, services in churches are held more solemnly than in ordinary days, for December 22 is the day “when the Blessed Virgin Mary was conceived.”

Equinox and solstice days 2017

vernal equinox - March 2010:29
summer solstice - June 21 04:24
autumnal equinox - September 22 20:02
winter solstice - December 21 16:28

Equinox and solstice days 2018

vernal equinox - March 20 16:15
summer solstice - June 21 10:07
autumnal equinox - September 23 01:54
winter solstice - December 21 22:23

Equinox and solstice days 2019

autumnal equinox - September 23 07:50
winter solstice - December 22 04:19
vernal equinox - March 20 21:58
summer solstice - June 21 15:54

Equinox and solstice days 2020

vernal equinox - March 20 03:50
summer solstice - June 20 21:44
autumn equinox - September 22 13:31

The benefits and necessity of sunlight for the human body are not in doubt. Any of us knows that without it it is impossible to exist. In winter, we all experience a more or less severe deficiency of it, which negatively affects our well-being and undermines our already unstable immunity.

What happens to daylight hours?

With the onset of the cold season, daylight hours, the duration of which is rapidly decreasing, are increasingly losing ground. The nights become longer and longer, and the days, on the contrary, become shorter. After the winter equinox, the situation begins to change in the opposite direction, which most of us are looking forward to. Many people want to accurately navigate the length of daylight hours now and in the near future.

As you know, the number of daylight hours in a day begins to increase after the end of the so-called winter solstice. At its peak, daylight hours are recorded annually, the duration of which is the shortest. From a scientific point of view, the explanation lies in the location of the sun at precisely this time at the most distant point in the orbit of our planet. This is influenced by the elliptical (i.e. elongated) shape of the orbit.

In the northern hemisphere it happens in December and falls on the 21st-22nd. A slight shift in this date depends on the dynamics of the Moon and shifts in leap years. At the same time, the southern hemisphere is experiencing the reverse of the summer solstice.

Daylight hours: duration, timing

A few days before and after the date of each solstice, the daylight does not change its position. Only two or three days after the end of the darkest day does the light period begin to gradually increase. Moreover, at first this process is practically invisible, since the increase occurs only for a few minutes a day. In the future, it begins to brighten faster, this is explained by an increase in the speed of solar rotation.

In fact, the increase in the length of daylight hours in the northern hemisphere of the Earth begins no earlier than December 24-25, and it occurs until the date of the summer solstice. This day alternately falls on one of three: from June 20 to June 22. Increasing daylight hours has a noticeable positive effect on people's health.

According to astronomers, the winter solstice is considered the moment the sun reaches its lowest angular height above the horizon. After it, within a few minutes the sunrise may begin even a little later (by a few minutes). An increase in the length of daylight hours is observed in the evenings and occurs due to an increasingly later sunset.

Why does this happen

This effect is also explained by the increase in the speed of the Earth's movement. You can verify this by looking at the table showing sunrises and sunsets. As astronomers say, the day increases in the evening, but unevenly on both sides. The graph of daylight hours gives a clear idea of the dynamics of this process.

Every day the sunset shifts by a few minutes. Accurate data can be easily tracked using the appropriate tables and calendars. As scientists explain, this effect is caused by a combination of the daily and annual movements of the sun across the sky, which is slightly faster in winter than in summer. In turn, this is caused by the fact that, rotating at a constant speed around its own axis, the Earth winter time is located closer to the Sun and moves in orbit around it a little faster.

The elliptical orbit along which our planet moves has a pronounced eccentricity. This term denotes the amount of elongation of an ellipse. The point of this eccentricity that is closest to the Sun is called perihelion, and the most distant point is called aphelion.

It is argued that a body moving in an elliptical orbit is characterized by maximum speed at those points that are as close as possible to the center. That is why the movement of the sun across the sky in winter is slightly faster than in summer.

How does the Earth's orbit affect climate?

According to astronomers, the Earth passes the perhelion point on approximately January 3, and aphelion on July 3. It is possible that these dates may change by 1-2 days, due to the additional influence of the Moon's movement.

The elliptical shape of the Earth's orbit also affects climate. During winter in the Northern Hemisphere, our planet is located closer to the Sun, while in summer it is further away. This factor makes the difference between climatic seasons our northern hemisphere.

At the same time, in the Southern Hemisphere this difference is more noticeable. As scientists have established, one revolution of the perhelion point occurs in approximately 200,000 years. That is, in about 100,000 years the situation will change to the exact opposite. Well, we'll wait and see!

Give me sunshine!

If we return to current problems, the most important thing for us is the fact that the emotional, mental and physical condition of the inhabitants of the Earth improves in direct proportion to the increase in the duration of daylight hours. Even a slight (several minutes) lengthening of the day immediately after the winter solstice has a serious moral effect on those tired of the dark winter evenings people.

Medically, positive influence sunlight on the body is explained by an increase in the production of the hormone serotonin, which controls the emotions of happiness and joy. Unfortunately, it is produced extremely poorly in the dark. That is why increasing the duration of the light interval by influencing the emotional sphere leads to a general improvement in well-being and strengthening of human immunity.

A significant role in the sensations of each of us is played by daily internal biorhythms, which are energetically tied to the alternation of day and night that has continued since the creation of the world. Scientists are confident that our nervous system can work adequately and cope with external overloads only by regularly receiving a very specific dose of sunlight.

When the light is not enough

If there are not enough sun rays, the consequences can be the saddest: from regular nervous breakdowns to serious mental disorders. With an acute lack of light, real depressive state. And seasonal affective disorders, which are expressed in depression, bad mood, a general decrease in the emotional background is observed quite often.

In addition, modern city dwellers are subject to another misfortune. Daylight hours, which are too short for modern city life, require adjustment. It's about about the huge, often excessive amount of artificial lighting that almost every resident of the metropolis receives. Our body, unadapted to such amounts of artificial light, is capable of getting confused in time and falling into a state of desynchronosis. This leads not only to weakening nervous system, but also to the exacerbation of any existing chronic diseases.

What is the length of the day

Let us now consider the concept of day length, which is relevant for each of us in the first days after the winter solstice. This term refers to the period of time that lasts from sunrise to sunset, that is, the time during which our star is visible above the horizon.

This value is directly dependent on the solar declination and the geographic latitude of the point where it needs to be determined. Near the equator, the length of the day does not change and is exactly 12 hours. This figure is borderline. For the northern hemisphere, in spring and summer the day lasts longer than 12 hours, in winter and autumn - less.

Autumn and spring equinox

Days when the length of the night coincides with the length of the day are called the days of the vernal or autumn equinox. This also happens on September 23rd, respectively. It is clear that the length of the day reaches its highest figure at the moment of the summer solstice, and the lowest - on the day of the winter.

Beyond the polar circles of each hemisphere, the length of the day goes off scale in 24 hours. We are talking about the well-known concept of polar day. At the poles it lasts as much as six months.

The length of the day at any point in the hemisphere can be determined quite accurately using special tables containing calculations of the length of daylight hours. Of course, this figure changes daily. Sometimes for a rough estimate he uses such a concept as average duration daylight hours by month. For clarity, let's consider these numbers for that geographical point, where the capital of our country is located.

Daylight hours in Moscow

In January, daylight hours at the latitude of our capital average 7 hours 51 minutes. In February - 9 hours 38 minutes. In March its duration reaches 11 hours 51 minutes, in April - 14 hours 11 minutes, in May - 16 hours 14 minutes.

For three summer months: June, July and August - these figures are 17 hours 19 minutes, 16 hours 47 minutes and 14 hours 59 minutes. We see that it is June, which corresponds to the summer solstice.

In autumn, daylight hours continue to decrease. In September and October, its duration is 12 hours 45 minutes and 10 hours 27 minutes, respectively. Record short on bright days The last cold, dark months of the year are famous - November and December, the average day length of which does not exceed 8 hours 22 minutes and 7 hours 16 minutes, respectively.