The number when day and night are equal. When day is equal to night. How long is the equinox

The night of December 21-22 will be the longest in 2018 in the entire northern hemisphere. This phenomenon occurs for the reason that it is at this time that the tilt of the Earth's axis of rotation relative to the Sun becomes greatest. In the calendar, this date is called the Winter Solstice.

The exact date and time of the winter solstice in 2018:

• GMT - December 21 22 hours 23 minutes GMT
• Kiev time - December 22 at 00 hours 23 minutes
• Moscow time - December 22 at 01 h 23 min

December 21 and 22 are the most short days year, and between them the longest night of the year. In the Southern Hemisphere, an astronomical summer will begin at the winter solstice. In astrology, the winter solstice is the moment when the Sun passes into the constellation Capricorn and the beginning of the astronomical winter, which will last right up to the vernal equinox.

• Video: Solstice and Equinox

The sun affects the earth. The fiery planet emits fluxes of light, and since our planet rotates on its axis, it turns out day and night.

• The fiery planet brings heat to the Earth, which, as a result of the movement of our planet around the celestial body, causes the change of seasons.
• Equinox and solstice days speak of astronomical seasonality.
• What days are these and when do they come? How does the day decrease and increase during these periods? You will find answers to these and other questions in this article.

What are the days of the vernal and autumnal equinox: definition

Summer solstice

Equinox is an astronomical event. During such a period, the Fiery Planet passes through the celestial equator. If you observe from the cosmic distance, then these days the line of light separation (terminator) goes clearly along the poles and it is located perpendicular to the earth's equator.

• A day like this is a unique natural manifestation.... Centre solar planet crosses the equator in the sky.
• On this day, our planet is tilted in such a way that the flow of rays goes directly towards the equator... The sun moves from the Southern Hemisphere to the Northern. Almost throughout the entire territory of the Earth, day is equal to night.
• On the day of the autumnal equinox, the Sun moves from the Northern Hemisphere to the Southern... Accordingly, in this hemisphere, March 21 is the autumn equinox, and September 23 is the spring one.
• The time period between two identical equinoxes is called a tropical year and is equal to 365.2422 days.

Due to the fact that the value is inaccurate, but approximate, the equality between day and night each year falls on a different time of day, moving 6 hours ahead. After 4 years, 1 day is added and this year is called a leap year.

The position of the sun on the days of the equinox

The days of the equinox are a kind of limit for the movement of the Fiery planet from the Northern Hemisphere to the Southern Hemisphere - in autumn, and vice versa in spring. This is typical for the territory of our planet that is located above the equatorial zone. These days, the celestial Luminary rises clearly in the east and hides behind the horizon in the west. This will be the position of the "bright" planet on days when day and night are compared in their time - in autumn and spring.

But such a phenomenon will definitely be observed on the territory in the region of 23.5 ° north or south latitude. In other areas, there may be little movement towards the north or south.

Vernal equinox day in 2018: date, day length

The vernal equinox is an important period in the annual seasonality.

• This day is considered the beginning of the astronomical spring. Our ancestors and modern people are looking forward to this period - warm days come after winter and cold weather, and daylight hours now begin to "add".
• This date is not considered to be fixed and every 365 days it can be in a different time period.
• The vernal equinox in 2018 is March 20.

At this time, the daytime is equal to the dark. Then every day it begins to increase by 1 minute, and during the summer solstice, the day will be the longest in the year.

Autumn equinox day in 2018: date, day length

In the period of the autumnal equinox, the astronomical autumn begins.

On the day of the autumnal equinox, the second time a year, when day is equal to night.

What are the days of the summer and winter solstices: definition

Solstice - translated from Latin "Solstitium" means "The sun has stopped".

June 20th or 21st the inclination of the axis of rotation of our planet from the North Pole in relation to the Sun has the smallest value.

December - 21st and 22nd, The sun in the Northern Hemisphere shines on the Southern Tropic.

• In this case, the axis of rotation of our planet from the North Pole in the direction from the Sun takes on the greatest value.
• On this day in the Northern Hemisphere, the shortest day and the longest night is the winter solstice.
• In the Southern Hemisphere, by contrast, the summer solstice.
• Due to the shift in leap years, the solstice days may be different, but this difference is no more than 1 day.

The position of the sun on the days of the solstice

The periods between two solstices are the times when the sun shifts to the side above the horizon and below this line. The movement of the celestial body is similar in trajectory to a sinusoid. In winter it sinks lower, in summer it rises higher. The angle between the sun and the horizon on our planet is:

• June - 90 degrees
• December - 270 degrees

A couple of days before and after the solstice period, the celestial Luminary “freezes” at one point at 12 noon. But you cannot observe it directly overhead. You need to go above the equator by 23.5 degrees in summer and similarly to 23.5 degrees south latitude in winter. So you will see the Sun directly vertical above you.

Summer solstice date 2018: day length, shortest night

The summer solstice date is the time when the Sun rises at its highest. In 2018, this date falls on June 21st. This period is the longest day and the shortest night of the year.

Winter solstice date 2018: day length, shortest day

The ancient Slavs called this day the Day of Renewal and the Birth of the Sun. Some nations even celebrated New Year on the day of the winter solstice. Winter solstice date in 2018: December 21. During this period, the longest night and the shortest day.

How the day decreases after the summer solstice: graph

Decrease in day after the summer solstice

As mentioned above, there is a decrease in the day after the summer solstice period by 1 minute every day. Above on the graph, you can see the longitude of the day in hours, it is indicated in green. Permanent day is shown in brown and night is white.

How the day after the winter solstice increases: graph

Analemma is a curved line in the form of a figure eight. It is written by the Sun in the sky during the calendar year. To draw such a curve, you need to fix the celestial body at the same time. Thanks to such an analemma, you can see how the Sun moves - rises and falls. After the winter solstice, the day increases by 1 minute every day.

Equinox and Solstice: Rites and Magic

Astrologers claim that the days of the solstices are the most dangerous period of the year. The energy of these days is weakened and can affect the inner state of a person. But folk signs claim the opposite. The days of the equinox are not so difficult, but they also have magical powers.

Thanks to magical rituals, you will be able to strengthen your energy and avoid the negative influence of the solar planet during these difficult periods. Meet this magical period in a good mood, so as not to enhance the already complex energy of such days. The inner state of a person should not be disturbed by anyone, even such changes in nature as the equinox and solstice.

Equinox is the time when day is equal to night. The moment the Sun crosses the equator from south to north is the vernal equinox, and from north to south it is the autumnal one. At this time, the Sun is directly above the Earth's equator. The word comes from the Latin equi, or equal, and the Greek nyx, or Latin nox, which means equal night.

Equinoxes and Solstices

Equinoxes occur at the intersection of the ecliptic and the celestial equator. On September 23, the Sun moves down from the celestial equator and crosses it - the autumn equinox, and on March 21 when it moves up - the vernal equinox... These days, the axis of the Earth is not tilted towards the Sun or far from it, and therefore the circle of illumination cuts all latitudes in half, which leads to the same duration of this day throughout the Earth.

In both cases, the solar illumination circle conventionally divides the equator in half. The Equator is an imaginary line with a latitude of 0 degrees that divides the planet into the Northern and Southern hemispheres. This is the only place on earth where day is always night, every day of the year.

The Earth is tilted, the maximum angular deviation to the Sun is 23.5 degrees. The day of June 21 with a positive deviation of the Sun from the celestial equator is called the summer solstice, and December 21 with a negative deviation is the winter solstice.

Simply put, the equinox represents the days when the day equals the night (March 21 and September 23), the solstice is the shortest (December 21) and long days (21st of June).

Equinoxes, along with solstices, are directly related to the seasons of the year.

Equinox - the name is deceiving

If the Earth's axis were perpendicular to its orbital plane, the entire Earth would have an equal length of day and night. A real sunny day has different lengths, with fluctuations up to 15 minutes.

There are three reasons for this temporary difference:

1. The movement of the Earth around the Sun is not a perfect circle, but eccentric.
2. The apparent movement of the Sun is not parallel to the celestial equator.
3. The phenomenon of the precession of the Earth's axis.

In addition, the Earth carries out two different types of motion:

• around the Sun in a fixed orbit, a journey that takes exactly 365.26 days (year);
• around its axis - forming day and night.

It takes not exactly 24 hours to complete one daily turnover, as we used to think, but 23.93 hours.

The earth is spherical, so half facing the sun is illuminated, while the other half is at night. The day / night cycle is continuous, with the exception of the earth's poles, where day and night are considered to last six months.

In fact, they are not, they are not equal. Just as the conventional wisdom regarding the equator, where day is equal to night all year round, is incorrect, then at the equator one would expect the Sun to rise at 6:00 AM and set at 6:00 PM. In fact, it rises at the equator at 6:03 am in July, 6:11 am in February, 5:53 am in May, and 5:40 am in late October.

This actual "non-equinox" phenomenon is caused by the Earth's axis being tilted at 23.4 degrees. The "inequality" of day and night is also influenced by the phenomenon of refraction. Refraction - the refraction of sunlight through the atmosphere, which visually prolongs the day. Because of this phenomenon, the top edge of the Sun can be seen even if it is just below the horizon. For example, it is usually seen in the morning a few minutes before the actual sunrise. This phenomenon is influenced by atmosphere pressure and temperature.

Therefore, the real duration of the "day" for the North Pole reaches 193 days, and nights - up to 172 days and, accordingly, for South Pole - 172 days are day and 193 days are night.

Earth precession motion

Due to the very slow movement of the firmament (in fact, the earth's axis is moving), the equinox Sun, when day is equal to night, moves from one zodiac sign to another about every 2160 years, completing the entire revolution in about 25.920 years. This very slow movement of the firmament is called the precession of the equinoxes. The precession of the equinoxes is the movement of the Earth that results in a change in the orientation of the rotation of the axis.

The first estimate of the earth's precession was made by Hipparchus in 130 BC. e.

The Earth's axis precesses due to the superposition of such factors:

• Its shape is not absolutely spherical (it is a flattened spheroid protruding at the equator).
• The gravitational forces of the Moon and the Sun acting on the equatorial ledge are trying to return it to the plane of the ecliptic.

Consequences of precession:

• displacement of the equinoxes;
• moving celestial poles;
• displacement of astrological zodiacal constellations.

The daytime and nighttime equinoxes are not the same length, their date varies depending on latitude.

The forces of nature are harmonious and consistent. The ancients were very attentive to the seasons and the position of the Sun in the sky, because their lives depended on the timely planting and harvesting.

Our ancestors have long celebrated the days of solstice and equinox as special holidays, when day is equal to night. Many great Orthodox holidays are still in the immediate vicinity of these dates: Christmas (winter solstice) and Easter (spring equinox).

Each person after a long and cold winter dreams of the imminent onset of the warm season. The vernal equinox 2018 will be the time when the Sun shifts to the northern hemisphere and the astronomical spring arrives.

When does this day come?

Equinox occurs when the length of day and night becomes the same. This moment is observed when the Sun crosses the equator of the sky. The vernal equinoxes are 365, 24 solar days apart from each other, so they come at different times. Now astronomers have learned how to accurately set the day of the equinox several years in advance. For those who are wondering what date this event will take place in 2018, we can already answer for sure. So, the sun's rays will fall vertically on the Earth's equator on 03/20/18.

A bit of history

In the history of mankind, four key dates can be noted, in accordance with which the life of ancient people was built. In 2018 they will look like this:

All these points are sacred. It is after these days that fundamental changes in nature come. The most revered date among our ancestors was the day of the vernal equinox. He was expected with the greatest impatience. He personified the victory of light and gave hope for the future. It is not surprising that many peoples perceive this day as a real holiday. The darkness begins to recede and the days increase. In ancient times, the equinox was associated with the onset of springtime. For some peoples, this day heralded the arrival of the New Year. After all, after him a new period began, when everything in nature and human life began to be renewed.

As for our people, in the Slavic world, Komoeditsa or Maslenitsa was celebrated at the equinox. On this day, it was customary to say goodbye to winter.

How they celebrate

The transition to a new life cycle was celebrated among all peoples with great enthusiasm. People tried to leave everything bad in the past and hoped that the new period would bring them victories and good luck. This, first of all, concerned the future harvest. This day was revered by almost all peoples of our planet. Europeans during this period held numerous festivals and masquerades.

AT pre-Christian Russiawhen the people worshiped pagan gods, the equinox was considered almost the most important day of the year. He was greeted with unprecedented joy and hope. The holidays lasted for several days and were called Pancake Week. Each day was dedicated to specific rituals:

• On Monday, the hostesses baked fragrant pancakes and larks, symbolizing the arrival of spring. The first pancake, according to custom, was intended for Whom - the bear God. It was believed that he protected men while hunting. On the same day, in Russian villages, a scarecrow was erected from straw and old things, they put it on a stake and drove it on a sleigh throughout the area.
• On Tuesday, the bride was arranged. In the early morning, the guys invited the girls to ride in a sleigh, and in the evening the matchmakers went to the houses of the future brides to discuss the details of the upcoming wedding.
• On Wednesday, mother-in-law invited their sons-in-law to visit for pancakes, showing them how much they respect them. On Thursday, in all Russian villages, festivities were held with noisy fascinating games and fairs, where you could taste pancakes with different fillings and enjoy old drinks. Young people danced and sang songs. The bravest ones took part in fist fights and jumped over the fire. The day ended with the capture of the "snow city". The goal of all the events of this day was to throw out the negative energy accumulated over the winter.
• On other days, older people performed all sorts of rituals aimed at obtaining a rich harvest and strengthening family ties (mother-in-law parties, sister-in-law gatherings, etc.)
• On Sunday, it was customary to ask each other for forgiveness. People also went to the bathhouse, trying to cleanse the accumulated dirt in order to put on new and clean clothes and put an end to the past. Old and dilapidated things these days had to be burned. The main event of this holiday, of course, is the burning of a straw effigy - a symbol of winter. Previously, the ashes from the scarecrow were scattered across the fields in the hope of getting a good harvest.

Currently, many traditions associated with the equinox have been lost. However, some Russian cities still hold fairs where you can taste pies, pancakes and other pastries. Performances of folk groups, master classes in various folk crafts are organized on the main squares. For this holiday, cafes and restaurants are adjusting their menu, including dishes of folk cuisine.

Signs

In the old days, when making baked goods, housewives put various household items into the products. So, if the household found in the lark, for example:

• a button, it meant a quick new thing;
• coin - wealth;
• flower - foreshadowed the owner of beauty;
• berry - was to health.

If a woman was pregnant, then on Shrove Tuesday it was easy to find out the sex of the unborn baby. If a man took the first pancake, then an heir would be born, if a woman, then a future mistress.

According to Maslenitsa, the weather for the next forty days was easily predicted. If there was a holiday warm weather, then during the next month it was possible to forget about the frosts and prepare for work on the ground.

In ancient times, people were sure that at the equinox the heavens were opened and the most secret desires were fulfilled. On this day, it was customary to ask God about the most important thing:

• about the future harvest;
• about the health and well-being of the whole family.

It was forbidden to be sad on this holiday. It was believed that on the day of the equinox everything could materialize, so crying and bad thoughts were forbidden. Joy and fun were the guarantee of a good mood for the whole year.

Equinox implies at least an elementary knowledge of astronomical terms, because the equinox itself is a phenomenon studied by this particular science.

Necessary knowledge of astronomical terms

Our star makes its movement along the ecliptic, which is, in unscientific language, the plane of the earth's orbit. And the moment when the sun, making its way along the ecliptic, crosses the celestial equator, which is a large air circle and parallel to the earth's equator (their planes coincide, and both of them are perpendicular to the axis of the world), is called equinox. also an astronomical concept that has nothing to do with Schwarzenegger) is a line that divides any celestial body into a part illuminated by the sun and into a "night" one. So, on the day of the equinox, it is this terminator that passes through the geographic poles of the Earth and divides it into two equal semi-ellipses.

The characteristic feature in the name

The name itself contains the concept that on the day of the equinox, night and day are equal. Scientifically, the night is always a little shorter, and the sun rises and sets, not exactly in the east and west, but slightly to the north. But still, from childhood, we know that June 22 is not only the day of the beginning of the war and school proms (this was soviet time), but also the day of the summer equinox. However, December 22 is also called the days of the summer and winter solstices. This happens because the sun in these periods of time is either at the highest point above the horizon, or at the lowest, and is farthest from the celestial equator. That is, on the day of the equinox, the light and dark parts of the day are practically equal to each other.

The number characteristic of the equinox and solstice

On the days of the solstices, one of them - either day or night - exceeds the other as much as possible. Equinox and solstice days are also remarkable for the fact that they serve as the beginning of the changing seasons. These dates are very remarkable, and always one of the family members says that, they say, today is the longest or shortest day, or that today is day equal to night. And this makes him stand out from the series of days following each other. Almost always, the date of these moments becomes the 22nd, but there are also leap years, and other moments and phenomena of astronomy that affect the shift of the date by 21 or 23. The months of March, June, September and December are the months of the equinox and solstice.

Holidays that came from ancient times

Of course, they have been known since ancient times. Our ancestors observed them and connected their lives with these dates, dozens of witnesses will accept this. Among the ancient Slavs, a certain holiday is associated with each of these days, and it usually lasts a week (Carols, Rusalii, Pancake week). So, on the winter solstice, Kolyada falls, a holiday later timed to coincide with Christmas. Great day, or Komoeditsa, aka Maslenitsa - these names mark the vernal equinox, the birth of a young sun. From this day, the astrological solar year begins, and our star passes into from the South. Perhaps that is why the astrology holiday falls on March 20. Kupala (other names are Ivan-day, Solstice), or summer confrontation, is a great summer holiday of the ancient Slavs, fanned with legends that glorified the brave people who went that night to look for a fern flower. Oat-Tausen, the day of the autumnal equinox, after which winter slowly begins to come into its own, and the nights are getting longer. Therefore, our ancestors in Svyatovit (another name) lit candles - the most beautiful was put in a place of honor.

Special climatic zone of the Earth

All of these dates served as starting points for the beginning of certain activities necessary for life - seasonal farming, construction, or stocking for the winter. The days of the vernal and autumnal equinox are also characterized by the fact that the sun gives off its light and heat equally to the Northern and Southern Hemispheres, and its rays reach both poles. These days it is located over the territory of such a climatic zone of the Earth as the tropics (translated from greek means turntable). In different directions from the equator to a little 23 degrees, parallel to it are the northern and southern tropics. A characteristic feature of the area enclosed between them is that above them twice a year the Sun reaches its zenith - once on June 22 over the northern tropic, or the Tropic of Cancer, the second time - over the South, or the Tropic of Capricorn. This happens on December 22. This is typical for all latitudes. North and south of the tropics at the zenith of the Sun never happens.

One of the consequences of shifting the direction of the earth's axis

On the days of the equinox and the solstice, it intersects with the celestial equator at points located in (spring) and Virgo (autumn), and on the days of the greatest and least distance from the equator, that is, on the days of the summer and winter solstices, in the constellations Taurus and Sagittarius, respectively ... From the zodiacal constellation Gemini to Taurus, the point of the summer solstice moved in 1988. Under the influence of the attraction of the Sun and the Moon, the earth's axis slowly shifts its direction (precession is another astronomical term), as a result of which the points of intersection of the star with the celestial equator also shift. Spring dates differ from autumn dates, and if September falls on the 22nd-23rd, then the question "When is the vernal equinox day?" the answer would be March 20. It should be stipulated that for the Southern Hemisphere the dates will be reversed - autumn will become spring, because the opposite is true there.

Role of the zodiac constellations

As noted above, the points of equinox are the points of intersection of the celestial equator with the ecliptic, and they have their own zodiac symbols corresponding to the constellations in which there are: spring - Aries, summer - Cancer, autumn - Libra, winter - Capricorn. It should be noted that the period of time between the two equinoxes of the same name is called a tropical year, the number of sunny days in which differs from about 6 hours. And only thanks to the leap year, which repeats once every 4 years, the running forward date of the next equinox returns to the previous number. With the Gregorian year, the difference is negligible (tropical - 365.2422 days, Gregorian - 365.2425), because this modern calendar is designed in such a way that even in the long term, the dates of the solstices and equinoxes fall on the same numbers. This happens because there is a pass for 3 days once every 400 years.

One of the most important practical tasks of astronomy is to establish the date of the equinox

Dates range from 1 to 2, no more than, days. So how to determine for the coming years when the day of the equinox? It is noticed that as a result of the presence of small fluctuations, the earliest dates, that is, the 19th, fall on leap years. Naturally, the latest (22) fall directly on the preceding leap. Earlier and later dates are very rare, the memory of them is kept for centuries. So, back in 1696, the vernal equinox fell on March 19, and in 1903 - the autumn equinox on September 24. Contemporaries will not see such deviations, because the repetition of the record of 1696 will fall on 2096, and the latest equinox (September 23) will not happen until 2103. There are nuances associated with local time - a deviation in the figure from the world time occurs only when the exact date falls on 24:00. After all, to the west of the starting point - the prime meridian - a new day has not yet arrived.

Equinox is such an astronomical period when the center of the Sun "crosses" the celestial equator, while it is completely perpendicular to the equator of the Earth. If we talk about the northern hemisphere, then on the autumn equinox, namely September 22 or 23, the Sun moves from the northern hemisphere to the southern. And at this time, the day is almost equal to the night, which is why it got its name. The Sun also rises almost strictly in the east and sets directly in the west.

Each nation celebrates this day in its own way, having its own traditions. For example, in Russia it is customary to bake cabbage or lingonberry pies, arrange festivities, insert rowan brushes between the window frames for protection. And for the Celts it is a harvest festival, a festival of autumn and wisdom. And they have their own rituals - they first demonstrate to everyone the best gifts of summer, and then eat them, which guarantees an abundance of food for the whole year.

Autumn is parting with summer
She sometimes cries, then laughs
Then suddenly it will rain
Then suddenly the sun will flood everything,
Equinox of nature
A variety of weather!
Day today is equal to night
Tomorrow it will be shorter
But this is tomorrow, and now,
With the equinox of all of you!
And although nature is fading away,
Don't let it scare you
She needs to rest too
Gain new strength, take a nap,
And I, in the autumn storms,
I wish you LOVE and HAPPINESS!

Autumn is in the yard
Brush leaves golden
And today is day and night
Identical exactly!

The equinox has arrived
An asterisk fell from the sky
May she bring you
Happiness, joy for the whole year!

The day has become equal to the night,
Autumn sends us its greetings.
On a magical day, I wish you
I am healthy for many years.

Equinox today -
The day is magical and difficult.
Let a surprise be sent to you
By willful fate.

On the autumn equinox
My congratulations,
Peace, harmony
I wish in my heart.

Let the foliage cover
From troubles and insults,
And the path to balance
Will be opened.

Autumn equinox day today
And there is no reason to be sad.
It's time to send your soul on a flight,
She should soar with joy.

I want smiles on this day to see the sea,
Let the veil of lies wear out forever.
So that your families prosper
Let their hearts be drunk with love.

Today we will celebrate the holiday.
After all, day and night are equal again!
It's close to winter
Don't borrow heat from us!

Equinox day now
Let the sun shine in the sky
To give us strength,
To live like in fabulous dreams!

The day has settled on the scales
On the second night settled down,
Happy children of the universe
Noisy son and quiet daughter.

The minutes were divided in half
The clock was divided for two,
Autumn equinox day
You gave us today.

I wish that nights and days
You filled with happiness to the brim
To live in harmony
And the minutes of love were not counted.

Autumn is playing outside the window
I brushed the leaves from the apple tree,
Equinox to visit us
On a day looked.

Day and night do not argue at all -
It's a day this fall.
The sun rose over the ground
The Quarter takes its source again!

May you achieve in life
You are the same height
Let it be like the sun at its zenith
You always shine for people!

Day and night have already converged on equal terms,
It means that we have crossed that threshold
When the summer was full
And now it's autumn evening

He reminded us that frost is near,
Cold, cold will soon be here
Autumn will take possession of a lush garden,
And shake off confident arrogance.

Give me your hand, let's sit with you
On a park bench by the stream
We are always - both in summer and in winter,
We will be together - just you and me!

Congratulations: 25 in verse.