Solstice
A solstice or equinox (Latin solstice, Greek ἡλιοστάσιον hēliostásion, standstill of the Sun ') is held twice a year. At the winter solstice - the northern hemisphere of the earth on 21 or 22 December - the sun reaches the lowest meridian altitude above the horizon during the summer solstice on 20, 21 or June 22 ( in places north of the Tropic of Cancer ) their midday peak above the horizon. In the southern hemisphere the situation is reversed, during the winter there is on the northern hemisphere summer.
In a solstice, the sun reaches over the course of a solar year the greatest distance north or south of the celestial equator. At this moment the sun reverses its caused by the obliquity of the ecliptic Deklinationsbewegung and again approaches the celestial equator.
This maximum declination reaches every year twice: once north and once south of the celestial equator; depending on the hemisphere (ie northern or southern hemisphere ) occurs in each case from the summer or winter solstice.
- 2.1 seasons
- 2.2 Festivals and Celebrations
- 2.3 Miscellaneous
Astronomical Foundations
Definition
The exact definition is: The solstices are the times in which the apparent geocentric ecliptic longitude of the Sun is 90 ° or 270 °.
- Apparently means taking account of aberration and nutation.
- Geocentric means seen by a fictitious observer at the center of the earth from. The definition is independent of the location of a real observer; Therefore, the solstices occur worldwide at the same time a ( but different depending on the local time zone times corresponds ).
The two time points fall to within a few minutes with those times together, where the sun its greatest northern or southern declination - about 23 ° 26 ' 20 " -. , And thus reaches its northernmost or southernmost position on the celestial sphere, the small time difference results from the fact that it actually is the barycenter of the earth / Moon system that evenly in the "Earth " ground plane ( ecliptic ) moves around the sun, while the earth itself revolves around this center of gravity and are generally slightly above or below this level is located. Geozentrum from viewed from the sun, therefore, does not exactly on the ecliptic (she has a non-zero ecliptic latitude ). happened to you therefore for a not exactly the northernmost or southernmost point of the ecliptic, on the other hand performs its variable ecliptic latitude to that the maximum declination is generally not accepted exactly at the solstice points.
Conclusions
The solstices mark the beginning of astronomical summer or the astronomical winter. When the sun reaches its greatest northern or southern declination of 23.4 °, it is perpendicular on the so-called turning circles of the earth ( ie the circles of latitude 23.4 ° north and south latitude ). It is therefore
- On 21 June, on the Tropic of Cancer (summer solstice in the northern hemisphere, the winter solstice in the southern hemisphere )
- On 21 or 22 December, on the Tropic of Capricorn ( winter solstice in the northern hemisphere, the summer solstice in the southern hemisphere ).
Each applies to both hemispheres: the winter solstice, the sun reaches its lowest level during the year in relation to the meridian passage. At this time, there is the shortest and the longest day night because the greater part of the daily path of the sun is below the horizon. Conversely, the sun reaches the summer solstice, its highest level to date At this time there is the longest day and the shortest night, because the greater part of the daily path of the sun is above the horizon.
Near the polar circles, there is the winter solstice, a day without sunrise and the summer solstice, a day without sun ( midnight sun, "White Nights "). Next there is poleward spend weeks or months of the polar day or the polar night at the other pole. During these periods the daily path of the sun is completely above or below the horizon.
Between the solstices the sun passes each of the celestial equator and is perpendicular to the equator of the earth. These time points are the equinoxes or equinoxes. Equinoxes and solstices represent the start of the respective astronomical seasons dar.
Although the day of the winter solstice is the shortest day, the earliest sunset for about ten days earlier and the latest sunrise occurs already only about ten days later. This is due to the equation of time. At the summer solstice makes this effect analogously from about four days.
Date
Because the solar year is almost six hours longer than the calendrical common year with exactly 365 days, the time of the solstices in years that are not leap years shifts to about six hours later times. In a leap year (eg 2012, 2016, 2020, and in the table in bold) jumps the appointment to balance again to about 18 hours back.
In the Central European Time zone, the summer solstice falls always present on June 21. In the 20th century it could also occur on June 22. In the 21st century, it will sometimes be from 2020 on June 20, because the switching rule ( 365.2425 days ) the actual length of the year can ( 365.2422 days ) represent only approximately. Without the Gregorian calendar reform her date per millennium would shift by seven to eight days. This reduction was the fact that - in contrast to the switching rule of the Julian calendar - the secular - years (ie years, whose number is divisible by 100 ) received no leap day, unless the year is divisible by 400.
The winter solstice falls in the Central European time zone is currently about the same frequency on the 21 and 22 December. By 2099 there will be more frequent 21 December, but after 2100 it evens itself out again, because 2100 is not a leap year.
For more details see the article in the season.
Winter and summer point point
At the moment of the winter solstice, the sun is compared to the background stars in the so-called winter point - the point of the ecliptic, which is exactly 90 ° from the vernal equinox ( RA = 18h). He is currently in the constellation of Sagittarius (Latin: sagittarius ); example in this direction is also the galactic center.
Similarly, the sun is at the moment of the summer solstice in the so-called summer period ( RA = 6h), between the constellations Taurus and Gemini.
Due to the precession of the Earth's axis of point winter and summer period ( cycle of precession ) migrate over the course of 25,780 years, even through the entire zodiac. So the winter point was in antiquity nor in the constellation Capricorn (hence " Tropic of Capricorn " ), and will move in about 300 years in the constellation Ophiuchus.
(Therefore also " Tropic of Cancer " ) The summer period was in the early antiquity in the constellation Cancer, his migration is represented in the following table through a whole cycle of precession. Taking the modern boundaries of the constellations to reason, then it is located in the following constellations:
At an angle of 90 ° to the summer and winter point each point of the vernal equinox are ( RA = 0h ) and the autumn period ( RA = 12h), in which the sun is at the equinox.
Solstitiallinie
The connecting line between the positions of the Earth at the time of the summer solstice and the winter solstice is called Solstitiallinie. This line is so right through the sun shining through, extending them beyond the Earth's orbit through the summer and the winter point point. It is perpendicular to the Äquinoktiallinie.
History and Culture
Seasons
The summer solstice is seen in many countries, such as in Central Europe and the USA, as the beginning of the season summer. In Ireland, however, the period from 1 May (see also Beltane ) is considered to 31 July as summer; So the summer solstice is located approximately in the middle of the season. In many countries where today the calendrical summer at 20-21. June begins the day of the summer solstice is still referred to as Midsummer, possibly going back to an old common Stone Age calendar. In Belchenhotel system is, for example, the sun on the summer solstice as seen from the Ballon d'Alsace from across the northeastern little Belchenhotel on, which allows the determination of the time of the summer solstice independent of anthropogenic objects.
Festivals and Celebrations
The worship of the sun and the recurring light goes back to traditions in prehistoric times. The sun was of crucial importance to the earthly survival. The summer solstice was an aspect of death and transience in itself. In contrast, the longer days were after the winter solstice, embodied the life and resurrection. These turning points had a correspondingly low in ritual and mythology. It is noteworthy that the sun is always assigned to the male principle in Western culture, but in this case an exception in the Germanic language area is that the mother sees the sun. Even the Tower of Jericho in the 9th millennium BC suggests the knowledge of the summer solstice, and later Stone Age cult sites such as Stonehenge recognized this time by means of the relatively easily identifiable on rising and setting points of the sun, or the beginning of winter as in the southeast. southwest lie. The Nebra Sky Disk as an important Bronze Age sites documenting the solstice.
As from 21-22. December, the days are getting longer, the winter solstice was in many ancient and early medieval cultures an important festival, celebrated often a few days before or after the date of the actual solstice. At the time of introduction of the Julian calendar, the solstice was on December 25 and June 24.
That Emperor Aurelian in the 3rd century to the 25th of December wide -ranging " dies natalis solis invicti " should have stated is controversial in the recent research. For a long time was thought the Christian Christmas (" the birth of the true sun," Jesus Christ ) for an overprinting of the pagan Roman emperor and solar cult. Today, it is from a parallel development. The day of the winter solstice was probably first occupied by the Christians, as no paganes solemnity took place at this time. For the year 354, the first certain mention of the pagan feast " Sol Invictus " in the city of Rome is detectable. Furius Dionysius Filocalus described this December 25th as the date of the birth of Jesus Christ in the Chronograph of 354 The development of the festivals in honor of their God obviously had the same Neoplatonic - solarmythologischen roots and stood in a narrow exchange. Both sides associated with the " emerging sun " at winter solstice.
It is disputed whether at least the northern Germanic tribes around the winter solstice celebrated the Yule. This would have been then practiced with fire and light symbolism of the winter solstice. Historically documented written testimonies are very few known, mainly in the form of calendar rods with runes.
The Christian Christmas, with the birth of Jesus is celebrated, will take place today shortly after the actual Winter Solstice. This coincides approximately with the St. Thomas Day of the Holy calendar on December 21. Since the Christianization of Europe, these celebrations are often connected to the Holy of June 24, St. John the Baptist, who was regarded as particularly powerful saint ( St. John's ). Some of the solstice customs that have survived to this day, as the bonfires are named after him. Again, the date is shortly after the actual summer solstice, there's the date in the Julian calendar was used.
The day of the summer solstice regarded as mystical day ever since some people; Some celebrate it with secular or religious ceremonies. Midsummer festivities had a permanent place especially in the Germanic, Nordic, Baltic, Slavic and Celtic religions.
The greater the difference between the harsh winters and hot summers, the more intense was celebrated from time immemorial this day. In the north of Europe, where in the summer season no longer the nights are dark ( it is also called the White Nights ), have solstice celebrations - known as Midsummer Festival - more important than, for example, in southern Europe.
Pagan or neo-pagan religious communities celebrate the solstice on 21, mostly with fire. Partly this festival is called Litha.
At the time of National Socialism, the supposedly ancient Germanic solstice celebrations were "revived " [note 1] and as official holidays in the symbolism of "people, blood and soil" integrated, especially by the SS
Midsummer celebrations are organized by different religious and philosophical communities as free religious and free-thinkers, clubs, parties like the SPD, volunteer fire departments, municipalities and tourism associations. In the GDR, the socialist youth organization organized Free German Youth solstice celebrations.
An important place for Midsummer celebrations are the external stones. This is followed participate under other followers neo-pagan and esoteric groups; However, the midsummer festival also attracts neo-Nazis.
A stir especially solstice celebrations of far-right groups. When a local club oriented solstice celebration Pretzien 2006 include an American flag and a copy of the diary of Anne Frank was burned without intervened others present. Since these events quite extreme solstice celebrations in Germany are increasingly dispersed by the police. In the press reported primarily on solstice celebrations politically radical right-wing and extreme right-wing groups. Also among the neo-pagan groups, there are those right-wing orientation as the Artgemeinschaft that has bonfires organized in 2010. For Ásatrú is the so-called Midsummer Festival, after the Yule, the second most important holiday of the year.
The southern summer solstice celebration takes place in the Spanish region of Alicante since 1929. The Golowan festival takes place in Cornwall, where Golowan is in the Cornish language for solstice. In India and Nepal in late December / early January Makar Sankranti takes place.
Others
Eratosthenes determined the circumference of the earth at a summer solstice ( high sun ).
William Shakespeare's comedy A Midsummer Night 's Dream (German "A Midsummer Night's Dream" ) is during a summer solstice in the classical unities of time, place and action of the closed-end drama. In addition to the other two Richard Wagner takes " the beautiful feast, St. John " ( bass aria ) as a classical unity of time in his comic opera The Mastersingers of Nuremberg: In keeping with the action on stage the world premiere in Munich June 21, 1868 took place on the solstice. " Smiles of a Summer Night " and Ingmar Bergman keeps to the three classical unities in his film of 1955 ( Sommarnattens leende ).
The typical June - summer weather and the mid-latitudes of the northern hemisphere still spring-like growth mood in nature is ideal for outdoor events of all kinds Thus, the solstice is a welcome occasion ( and in some conscious reason) for parties or celebrations to this day around.
The largest unorganized summer solstice celebration in Europe takes place at Stonehenge, the largest in Germany at the Extern Stones.