The equinoxes are the time of year when. Day of spring equinox. Earth's Precession Movement

Solstice(also solstice) - an astronomical event, the moment of passage of the center of the Sun through the points of the ecliptic, most distant from the equator of the celestial sphere and called solstice points.

Equinox- an astronomical phenomenon when the center of the Sun, in its apparent movement along the ecliptic, crosses the celestial equator. When observing the Earth from space at the equinox, the terminator passes along the geographic poles of the Earth and is perpendicular to the Earth's equator.

These dates were among the most revered in the pre-Christian period. Solstice, rotation, equinox, solstice are the names of solar holidays, which are also called the four hypostases of the Slavic Dazhdbog, which is the Sun itself - the son of Svarog.

• Kolyada– winter solstice (December 21-22)
• Maslenitsa or Komoeditsy- day spring equinox(March 21-22)
• Kupailo (Kupala)– summer solstice (June 21-22)
• Radogoshch (Svetovit, Veresen, Tausen)– autumnal equinox (September 22-23)

Kolyada– winter solstice or most long night per year. During this period, the young sun Kolyada replaces the old sun Svetovit in his post. That is why the daylight hours begin to increase from this day on. Replaced by the church on Christmas Day.

Maslenitsa or Komoeditsy– the day of the vernal equinox (day and night are equal in time), farewell to winter, burning of the effigy of Madder, welcoming spring and the Slavic New Year. The date March 21-22 is also the beginning of astronomical spring. From this day on, the day becomes longer than the night. Yarilo-Sun replaces Kolyada and drives away Winter-Madder. Traditionally, this bracelet was celebrated for two whole weeks.

Kupaylo- day of the summer solstice. The longest day and shortest night of the year. The last day of Rusal Week or Rusalia. Kupala is one of the oldest holidays, which has kept many traditions and customs unchanged to this day, for example: the funeral of Yarila, who is replaced by God summer sun Bathed, collected medicinal herbs, searched for fern flowers, etc. Kupailo is also a great holiday, which is now replaced by the church on the birthday of John the Baptist.

Radogoshch(Svetovit, Veresen, Tausen) - the day of the autumnal equinox (day and night are equal in time). On this day, the Sun-Old Man Svetovit comes into his own. The night becomes longer than the day. It is both a solar holiday and a celebration of the end of the harvest. Replaced by the church for the Nativity of the Blessed Virgin Mary.

Position of the sun on solstice days

The periods between solstices are the times when the sun moves either higher above the horizon or lower.

Astronomers note that the movement of the hot star is similar to a sine wave:

• after the winter solstice it rises higher every day
• after the summer - on the contrary, it drops lower

The angle created by the sun and the earth's horizon, in other words, the astronomical longitude of the hot star, is:

• 90° in June
• 270° in December

In astronomy, from the moment the Sun enters the zodiac sign of Taurus in June, summer begins, and winter begins in the sign of Sagittarius in December. A few days before and after the solstice, the hot celestial body “freezes” at one point at noon.

However, you won't see the sun directly overhead on the solstices.

If you are a resident of the northern hemisphere of the Earth, then:

• go 23.5° above the equator before the summer solstice to see the hot planet vertically above you,
• visit 23.5°S to see a similar phenomenon during the winter solstice.

Position of the sun at the equinoxes

The equinoxes represent a certain milestone when the sun moves from the northern to the southern hemisphere in the fall and vice versa in the spring. This is for the part of our planet that is located above the equator. These days the sun directs its rays in such a way that they evenly heat the entire part of the Earth facing it.

Another feature of these calendar dates– the day before and after, as well as during the equinox, the sun rises clearly in the east and sets in the west. Is it true, this phenomenon typical only for 23.5° north or south latitude. In other areas there is a slight shift to the north or south.

Equinoxes and solstices: magic

These 4 days of the year have maximum energy not only because of the change of times. The Slavs knew this very well and harmoniously structured their lives in such a way as to streamline and develop their relationships with nature.

A common feature during the celebrations of all solstices and equinoxes among our ancestors were mass celebrations.

The whole village gathered together:

• were carried out different games and fun
• there were round dances
• everyone ate
• praised the gods
• commemorated ancestors

Everything happened fun, easily and naturally.

• We still celebrate the summer solstice as Kupala. We are looking for the treasured fern flower in the hope of good luck and the fulfillment of our cherished dreams.
• On the autumn equinox, the ancestors held a harvest festival. Adults cleaned the house, yard, and fields. Children decorated their homes with bunches of rowan berries. It was believed that she would protect the house and its inhabitants from evil all year long.

The winter solstice, or the birth of Kolyada - the young sun, was celebrated on a special scale. There was a place here:

• fortune telling about the betrothed, marriage, weather next year, harvest
• caroling and dressing up as animals to scare away dark forces
• jumping over a fire to burn all resentment, envy and similar sins

Three days before and the same number after Kolyada had special power. Housewives put things in order in their heads and homes, and brought health and well-being into the life of the family. They watched the events of 12 days after Kolyada in order to understand what the coming year would bring for the family.

• The day of the spring equinox had special power. Nature was awakening from its winter sleep, New Year for work on the ground.
• At this time pancakes were being baked and it was Maslenitsa. But it lasted 2 weeks - one before, the second after the equinox.
• Housewives baked larks - small birds made from sweet dough.
• In the evening, everyone jumped over the fires to renew themselves for a new round of life. For example, if an unmarried girl jumped, then she will definitely become the mother of a hero.

Hello, dear readers of the Sprint-Response website. In this article we will find out the answer to the question about the place on globe where is the day equal to night throughout the year. The question was asked in the game "Who want to be a millionaire?" dated October 28, 2017, a review of which can be read by following the link above. This question also often appears in numerous quizzes.

Where on the globe is day equal to night throughout the year?

The correct answer is highlighted in blue and in bold, the list of answer options can be seen below. And here's what Wikipedia tells us about this.

The length of the day depends on geographical latitude place and from the declination of the Sun. At the earth's equator it is approximately constant and amounts to 12 hours 7 minutes; deviations from half a day are due to the very definition of sunrise and sunset, since sunrise and sunset are traditionally considered the moment the upper edge of the solar disk intersects the visible horizon, and not the moment the center of the Sun intersects the true horizon. In addition, the refraction of sunlight also affects the length of the day. The inclination of the earth's axis to the ecliptic plane determines fluctuations in the length of the day. In the Northern Hemisphere of the Earth, the length of the day is more than 12 hours from mid-March to the end of September, and with increasing latitude it increases to the polar day. From the end of September to mid-March it is less than 12 hours and with increasing latitude the length of the day decreases to the polar night. In the Southern Hemisphere it is the other way around: from mid-March to the end of September it is less than 12 hours.

8. Where on the globe is day equal to night throughout the year?

• at the poles
• on the Arctic Circle
• on the prime meridian
• at the equator

There are four moments in the annual cycle that play a significant role in life on Earth.

People have long known about the existence of these transition points, but the physical essence of these phenomena became clear only with the development. It's about about two solstices (winter and summer) and two equinoxes (spring and autumn).

What is solstice?

At the everyday level, we understand that the solstice is the day with the longest (summer solstice) or shortest (winter solstice) daylight hours. Our distant ancestors knew well that before the winter solstice the day shortens, and after it begins to increase. In summer, the opposite happens. It was also noticed that on the day of the winter solstice the sun occupies its lowest position above the horizon, and at the moment of the summer solstice it passes the highest point for the entire year.

What is happening to our planet and the Sun from a scientific point of view? Let's remember some astronomical concepts.

Celestial sphere- an imaginary surface that we look at when we are on Earth and looking around the sky. For us, earthly observers, it is along the celestial sphere that all celestial objects, including the Sun, move.

Ecliptic- a circle located on the celestial sphere along which the Sun moves relative to the Earth.

celestial sphere– a circle located perpendicular to the celestial sphere coincides with the Earth’s equator.

Due to the fact that the Earth's axis is inclined to the planet's orbit around our star, the equator of the celestial sphere and the ecliptic do not coincide. Due to this, the seasons change with moments of transition - solstices.

On the day of the solstice, the Sun passes through the points of the ecliptic that are furthest from the celestial equator. Otherwise, this can be expressed this way: solstices are the moments of the greatest (in winter) or smallest (in summer) deviation of the earth’s axis from the Sun.

Winter and summer solstice

The winter solstice occurs on December 21 or 22 (the date may vary in different time zones). This day marks the shortest daylight hours and longest night in the northern hemisphere. The summer solstice falls on June 21 and is distinguished by the fact that this date has the longest daylight hours and the shortest night.


In the southern hemisphere, exactly the opposite processes occur: there is a summer solstice in December, and a winter solstice in June.

What is an equinox?

There are two more important points in the annual cycle - the days of the spring and autumn equinoxes. These days the Sun passes the intersection points of the celestial equator and the ecliptic. The days of the equinoxes fall in the middle of the period from one solstice to the next (although due to the fact that the earth moves around the Sun not in a circle, but in an ellipse, the dates shift slightly).

The spring equinox falls on March 20 or 21, the autumn equinox on September 22 or 23. As the name suggests, equinoxes are the times when day is equal in length to night.

How do the solstices and equinoxes affect life on Earth?

People have always known that critical points in the movement of our star across the celestial sphere affect nature. This is especially true for residents of northern latitudes, where the change of seasons is more pronounced. For example, from the day of the March equinox, real spring comes to us: it becomes warmer, the soil warms up, and plants come to life. This is of great importance for agriculture.

It is no coincidence that the agricultural calendar has always been associated with the days of the solstices and equinoxes. Important pagan holidays fell on these dates, some of which were adopted by Christianity. These holidays are:

Winter solstice - Catholic Christmas and Kolyada;

Spring equinox - Maslenitsa;

Summer solstice - the holiday of Ivan Kupala;

The autumn equinox is a harvest festival.


As you can see, even in the technocratic 21st century we celebrate these events without even thinking that they are related to the annual solar cycle and how dependent our ancestors were on natural phenomena.

The equinox is the time when day is equal to night. At the moment when the Sun crosses the equator from south to north - this is the day of the spring equinox, and from north to south - the autumn equinox. 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, meaning equal night.

Equinoxes and solstices

The 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 autumnal equinox, and on March 21, when it moves upward, it is the spring equinox. On these days, the Earth's axis is not inclined towards the Sun or far from it, and therefore the circle of illumination cuts all latitudes in half, which leads to the same length of this day throughout the Earth.

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

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

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

The equinoxes, together with the solstices, are directly related to the seasons of the year.

Equinox - the name is deceptive

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

There are three reasons for this timing difference:

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

In addition, the Earth undergoes 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.

To complete one daily revolution, it takes not exactly 24 hours, as we used to think, but 23.93 hours.

The Earth is spherical, so the half facing the Sun is illuminated, while the other half is at night. The day/night cycle is continuous, except at the Earth's poles, where day and night are thought to last for half a year.

In fact, this is not true, they are not equal. Just as the generally accepted opinion regarding the equator, where day is equal to night, is wrong all year round, 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 phenomenon of actual "non-equinox" is caused by the fact that the Earth's axis is tilted at an angle of 23.4 degrees. The “inequality” of day and night is also influenced by the phenomenon of refraction. Refraction - refraction sunlight through the atmosphere, thereby visually prolonging the day. Because of this phenomenon, the top edge of the Sun can be visible even if it is just below the horizon. For example, it is usually visible in the morning a few minutes before the actual sunrise. This phenomenon is influenced Atmosphere pressure and temperature.

Therefore, the real duration of the “day” for the North Pole reaches 193 days, and the night - up to 172 days and, accordingly, for the South Pole - day lasts 172 days and night lasts 193 days.

Earth's Precession Movement

Due to the very slow movement of the firmament (actually the earth's axis moves), the equinoctial Sun, when day is equal to night, moves from one zodiac sign to another approximately every 2160 years, completing its entire revolution in approximately 25,920 years. This very slow movement of the sky is called the precession of the equinoxes. The precession of the equinoxes is the movement of the Earth, which results in a change in the orientation of the rotation axis.

The first estimate of 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 completely spherical (it is an oblate spheroid protruding at the equator).
• The gravitational forces of the Moon and the Sun acting on the equatorial protrusion try to return it to the ecliptic plane.

Consequences of precession:

• shift of the equinoxes;
• movement of the celestial poles;
• displacement of astrological zodiac constellations.

The daytime and nighttime equinoxes are not the same length; their dates vary depending on latitude.

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

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

Equinoxes imply at least basic knowledge of astronomical terms, because the equinox itself is a phenomenon studied by this particular science.

Required knowledge of astronomical terms

Our star moves along the ecliptic, which is, in non-scientific 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 circle of air and parallel to the earth’s equator (their planes coincide, and both of them are perpendicular to the axis of the world), is called the equinox. also an astronomical concept that has nothing to do with Schwarzenegger) is a line that divides any celestial body into the sunlit part and the “night part”. 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 half-ellipses.

Characteristic feature contained in the name

The name itself contains the concept that on the day of the equinox, night and day are equal. From a scientific point of view, 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 the war began and school proms(this was the case in Soviet time), but also the day of the summer equinox. However, December 22 is also called the summer and winter solstice. This happens because the sun during these periods of time is either at the highest point above the horizon, or at the lowest, and farthest from the celestial equator. That is, on the day of the equinox, the light and dark parts of the day are almost 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 - maximally exceeds the other. The equinoxes and solstices are also notable for the fact that they mark the beginning of the changing seasons. These dates are very remarkable, and one of the family members always says that today is the longest or shortest day, or that today is day equal to night. And this sets him apart from the series of consecutive days. 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 date shift to the 21st or 23rd. The months of March, June, September and December are those in which the equinoxes and solstices fall.

Holidays that come 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 signs bear witness to this. The ancient Slavs have a specific holiday associated with each of these days, and it usually lasts a week (Carols, Rusalia, Maslenitsa Week). So, on the winter solstice there is Kolyada, a holiday later dedicated to Christmas. Great Day, or Komoeditsa, also known as Maslenitsa - these names mark the spring equinox, the birth of the young sun. From this day the astrological solar year begins, and our luminary moves to from the South. Maybe that’s why March 20 is an astrological holiday. Kupala (other names Midsummer Day, Solstice), or summer confrontation, is a great summer holiday of the ancient Slavs, covered in legends that glorified brave people who went out that night to look for a fern flower. Ovsen-Tausen, the day of the autumn equinox, after which winter slowly begins to take over, and the nights become longer. Therefore, our ancestors lit candles in Svyatovit (another name) - the most beautiful one was placed in a place of honor.

Special climate zone of the Earth

All these dates served as starting points for the beginning of certain activities necessary for life - seasonal types of agriculture, construction or winter supplies. The days of the spring and autumn equinox are also characterized by the fact that the sun gives off its light and heat equally to both the Northern and Southern Hemispheres, and its rays reach both poles. These days it is located above the territory of such a climatic zone of the Earth as the tropics (translated from Greek it means a turning circle). In different directions from the equator to a little over 23 degrees, parallel to it are the northern and southern tropics. Characteristic feature 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 Tropic of Cancer, the second time - over the southern, or Tropic of Capricorn. This happens on December 22. This is typical for all latitudes. The Sun is never at its zenith north or south of the tropics.

One of the consequences of a shift in the direction of the earth's axis

On the days of the equinox and solstices, it intersects with the celestial equator at points located in (spring) and Virgo (autumn), and on the days of 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 . The summer solstice point moved from the zodiac constellation Gemini to Taurus in 1988. Under the influence of the attraction of the Sun and Moon, the earth's axis slowly shifts its direction (precession is another astronomical term), as a result of which the intersection points of the star with the celestial equator also shift. Spring dates differ from autumn dates, and if September falls on the 22nd-23rd, then to the question “When is the vernal equinox?” the answer will be March 20th. It must be stated that for Southern Hemisphere the dates will switch places - autumn ones will become spring ones, because everything is the other way around.

The role of the zodiac constellations

As noted above, the equinox points are the intersection points of the celestial equator with the ecliptic, and they have their own zodiac symbols corresponding to the constellations in which they are located: spring - Aries, summer - Cancer, autumn - Libra, winter - Capricorn. It should be noted that the period of time between two equinoxes of the same name is called a tropical year, the number of solar days in which differs by approximately 6 hours. And only thanks to the leap year, which repeats itself once every 4 years, does the date of the next equinox, which runs ahead, return to its previous date. The difference with the Gregorian year 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 dates. This happens because it provides for a 3-day pass once every 400 years.

One of the most important practical tasks of astronomy is establishing the date of the equinox.

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