View source for Astronomy:Winter solstice

{{Short description|Astronomical phenomenon}}

{{Infobox holiday
| holiday_name=Winter solstice
| image=Stonehege (2148722919) (cropped).jpg
| caption= Sunset at [[Unsolved:Stonehenge|Stonehenge]] in England during the winter solstice in the Northern Hemisphere
| observedby=Various cultures
| date= 21 or 22 December <br> ([[Earth:Northern Hemisphere|Northern Hemisphere]]) <br>  and 20 or 21 June <br> ([[Earth:Southern Hemisphere|Southern Hemisphere]])
| celebrations=Feasting
| type=Cultural, astronomical
| significance=Beginning of lengthening days and shortening nights
| relatedto=Winter festivals
| nickname= Midwinter; the Shortest Day; the Longest Night
| duration=1 day
}}
[[File:North season.jpg|thumb|The seasons with the transition points of the June solstice, September equinox, December solstice, and March equinox|upright=1.2]]
The '''winter solstice''', also called the '''hibernal solstice''', occurs when either of [[Astronomy:Earth|Earth]]'s [[Earth:Geographical pole|poles]] reaches its maximum [[Astronomy:Axial tilt|tilt]] away from the [[Astronomy:Sun|Sun]]. This happens twice yearly, once in each hemisphere ([[Earth:Northern Hemisphere|Northern]] and [[Earth:Southern Hemisphere|Southern]]). For that hemisphere, the winter [[Astronomy:Solstice|solstice]] is the day with the shortest [[Astronomy:Daytime|period of daylight]] and longest night of the year, and when the Sun is at its lowest [[Astronomy:Culmination|daily maximum elevation]] in the sky.<ref>{{cite book |title=An Introduction to Physical Science |edition=12th |first1=James |last1=Shipman |first2=Jerry D. |last2=Wilson |first3=Aaron |last3=Todd |chapter=Section 15.5 |page=423 |isbn=978-0-618-92696-1 |year=2007 |location=Boston|publisher=Houghton Mifflin}}</ref> Each polar region experiences [[Earth:Polar night|continuous darkness]] or [[Earth:Twilight|twilight]] around its winter solstice.

The winter solstice occurs during the hemisphere's winter. In the Northern Hemisphere, this is the [[Astronomy:December solstice|December solstice]] (21 or 22 December) and in the Southern Hemisphere, this is the [[Astronomy:June solstice|June solstice]] (20 or 21 June). Although the winter solstice itself lasts only a moment, the term also refers to the day on which it occurs.  The term midwinter is also used synonymously with the winter solstice, although it carries other meanings as well. Traditionally, in many [[Earth:Temperate climate|temperate]] regions, the winter solstice is seen as the middle of winter; although today in some countries and calendars it is seen as the beginning of winter. Other names are the "extreme of winter" (''Dongzhi''), or the "shortest day".

Since prehistory, the winter solstice has been a significant time of year in many cultures and has been marked by festivals and rites.<ref>{{cite web|url=http://www.religioustolerance.org/winter_solstice.htm|title=Winter Solstice celebrations: a.k.a. Christmas, Saturnalia, Yule, the Long Night, the start of Winter, etc.|date=August 5, 2015 |orig-year=December 3, 1999|publisher=Religious Tolerance.org}}</ref> It marked the symbolic death and rebirth of the Sun; the gradual waning of daylight hours is reversed and begins to grow again. Some ancient monuments such as [[Astronomy:Newgrange|Newgrange]], [[Unsolved:Stonehenge|Stonehenge]], and [[Astronomy:Cahokia Woodhenge|Cahokia Woodhenge]] are aligned with the sunrise or sunset on the winter solstice.

== History and cultural significance ==

There is evidence that the winter solstice was deemed an important moment of the annual cycle for some cultures as far back as the [[History:Neolithic|Neolithic]] (New Stone Age). Astronomical events were often used to guide farming activities, such as the mating of animals, the sowing of crops and the monitoring of winter reserves of food. The winter solstice was important because the people were economically dependent on monitoring the progress of the seasons. Starvation was common during the first months of the winter, January to April (northern hemisphere) or July to October (southern hemisphere). Livestock were slaughtered so they would not have to be fed during the winter, so it was almost the only time of year when a plentiful supply of fresh meat was available.<ref>{{cite web|url=http://www.history.com/topics/christmas/history-of-christmas | title=History of Christmas |publisher=History.com |access-date=January 2, 2017}}</ref>

Because the winter solstice is the reversal of the Sun's apparent ebbing in the sky, in ancient times it was seen as the symbolic death and rebirth of the Sun or of a Sun god.<ref>Krupp, E C. ''Echoes of the Ancient Skies: The Astronomy of Lost Civilizations''. Courier Corporation, 2012. pp. 119, 125, 195</ref><ref>North, John. ''Stonehenge''. The Free Press, 1996. p. 530</ref><ref>Hadingham, Evan. ''Early Man and the Cosmos''. University of Oklahoma Press, 1985. p. 50</ref> In cultures which used cyclic calendars based on the winter solstice, the "year as reborn" was celebrated with reference to life-death-rebirth deities or "new beginnings" (such as Hogmanay's ''redding'', a New Year cleaning tradition), and "reversal" (as in Saturnalia's slave and master reversals).{{Citation needed|date=February 2020}}

===Neolithic Europe===
[[File:2013 Solstice Newgrange.jpg|Sunlight entering the passage of Newgrange in Ireland on the winter solstice|thumb|upright]]
Some important [[History:Neolithic Europe|Neolithic]] and early [[History:Bronze Age|Bronze Age]] archaeological sites in Europe are associated with the winter solstice, such as [[Unsolved:Stonehenge|Stonehenge]] in England and [[Astronomy:Newgrange|Newgrange]] in Ireland. The primary axes of both of these monuments seem to have been carefully aligned on a sight-line pointing to the winter solstice sunrise (Newgrange) and the winter solstice sunset (Stonehenge). It is significant that at Stonehenge the Great [[Unsolved:Trilithon|Trilithon]] was oriented outwards from the middle of the monument, i.e. its smooth flat face was turned towards the midwinter Sun.<ref>{{cite book |last1=Johnson |first1=Anthony |title=Solving Stonehenge: The New Key to an Ancient Enigma |publisher=Thames & Hudson |year=2008 |isbn=978-0500051559 |pages=252–253}}</ref>

===Ancient Roman===
In the ancient Roman calendar, December 25 was the date of the winter solstice.<ref>{{cite book |last1=O'Neill |first1=William Matthew |title=Time and the Calendars |date=1976 |publisher=Manchester University Press |page=85}}</ref><ref name="Forsythe">{{cite book |last1=Forsythe |first1=Gary |title=Time in Roman Religion: One Thousand Years of Religious History |date=2012 |publisher=Routledge |pages=113, 123, 141}}</ref> In AD 274, the emperor Aurelian made this the date of the festival {{lang|la|Dies Natalis Solis Invicti}}, the birthday of {{lang|la|[[Religion:Sol Invictus|Sol Invictus]]}} or the 'Invincible Sun'.<ref name="Forsythe"/><ref name="Bradshaw">{{cite book |last1=Bradshaw |first1=Paul |editor1-last=Larsen |editor1-first=Timothy |title=The Oxford Handbook of Christmas |date=2020 |publisher=Oxford University Press |pages=4–10 |chapter=The Dating of Christmas}}</ref> Gary Forsythe, Professor of Ancient History, says "This celebration would have formed a welcome addition to the seven-day period of the ''Saturnalia'' (December 17–23), Rome's most joyous holiday season since Republican times, characterized by parties, banquets, and exchanges of gifts".<ref name="Forsythe"/> 

A widely-held theory is that the Church chose December 25 as Christ's birthday ({{lang|la|Dies Natalis Christi}}) to appropriate the Roman winter solstice festival marking the sun god's birthday ({{lang|la|Dies Natalis Solis Invicti}}).<ref name="Bradshaw"/><ref name="Forsythe"/><ref>{{Cite journal |last=Nothaft |first=C. P. E. |date=December 2012 |title=The Origins of the Christmas Date: Some Recent Trends in Historical Research |url=https://www.cambridge.org/core/journals/church-history/article/abs/origins-of-the-christmas-date-some-recent-trends-in-historical-research/3767138672A4C2DFBED6BD1B004FB78A |journal=Church History |language=en |volume=81 |issue=4 |pages=903–911 |doi=10.1017/S0009640712001941 |s2cid=145151430 |issn=0009-6407}}</ref>

===Germanic===
[[File:Goseck-2.jpg|Neolithic site of Goseck circle in Germany. The yellow lines indicate the directions in which sunrise and sunset are seen on the day of the winter solstice.|thumb|upright]]
In Anglo-Saxon England the winter solstice was generally deemed to be 25 December, and in [[Social:Old English|Old English]], ''midwinter'' could mean both the winter solstice and Christmas.<ref name="Menologium">{{cite book |last1=Karasawa |first1=Kazutomo |title=The Old English Metrical Calendar (Menologium) |date=2015 |publisher=Boydell & Brewer |pages=36–37}}</ref><ref>{{cite book |last1=Parker |first1=Eleanor |title=Winters in the World: A Journey through the Anglo-Saxon Year |date=2023 |publisher=Reaktion Books |pages=70–71}}</ref>

The North Germanic peoples celebrated a winter holiday called Yule. The ''Heimskringla'', written in the 13th century by the Icelander Snorri Sturluson, describes a Yule feast hosted by the Norwegian king Haakon the Good (c. 920–961). According to Snorri, the Christian Haakon had moved Yule from "midwinter" and aligned it with the Christian Christmas celebration. Historically, this has made some scholars believe that Yule originally was a sun festival on the winter solstice. Modern scholars generally do not believe this, as midwinter in medieval Iceland was a date about four weeks after the solstice.<ref>{{cite book |last=Nordberg |first=Andreas |year=2006 |url=https://www.academia.edu/1366945 |title=Jul, disting och förkyrklig tideräkning: Kalendrar och kalendariska riter i det förkristna Norden |series=Acta Academiae Regiae Gustavi Adolphi |language=sv |volume=91 |publisher=Kungl. Gustav Adolfs Akademien för svensk folkkultur |pages=120–121 |isbn=91-85352-62-4 |issn=0065-0897 }}</ref> During the Christianisation of the Germanic peoples, Yule was incorporated into the Christmas celebrations and the term and its cognates remain used to refer to Christmas in modern Northern European languages such as English and Swedish.<ref>{{cite web |title=Yule |url=https://en.wiktionary.org/wiki/Yule |website=Wiktionary |access-date=26 March 2023 |language=en |date=17 March 2023}}</ref><ref>{{cite web |title=jul |url=https://en.wiktionary.org/wiki/jul#Swedish |website=Wiktionary |access-date=26 March 2023 |language=en |date=17 March 2023}}</ref>

===East Asian===
[[File:Origin_of_Iwato_Kagura_Dance_Amaterasu_by_Toyokuni_III_(Kunisada)_1856.png|thumb|Japanese Sun goddess [[Religion:Amaterasu|Amaterasu]] emerging from a cave (by Kunisada)]]
[[File:Seventeen Arch Bridge at winter solstice sunset (20201222160213).jpg|thumb|Sunlight directed through the 17 arches of Seventeen Arch Bridge, Summer Palace, Beijing around winter solstice]]
In [[Place:East Asia|East Asia]], the winter solstice has been celebrated as one of the Twenty-four Solar Terms, called ''Dongzhi'' (冬至) in [[Social:Chinese language|Chinese]]. In {{wipe|Japan}}, in order not to catch [[Medicine:Common cold|cold]] in the winter, there is a custom to soak oneself in a [[Biology:Yuzu|yuzu]] hot bath ({{Lang-ja|柚子湯}} = Yuzuyu).<ref>[http://goinjapanesque.com/06216/ Goin’ Japanesque!: Japanese Winter Solstice Traditions; A Day for Kabocha and Yuzuyu]</ref>

===Indian===
Makara Sankranti, also known as Makara Sankrānti ([[Social:Sanskrit|Sanskrit]]: मकर संक्रांति) or Maghi, is a festival day in the Hindu calendar, in reference to deity [[Religion:Surya|Surya]] (sun). It is observed each year in January.<ref name="Tumuluru2015p30"/> It marks the first day of Sun's transit into [[Unsolved:Capricorn (astrology)|Makara (Capricorn)]], marking the end of the month with the winter solstice and the start of longer days.<ref name="Tumuluru2015p30">{{cite book|author=Kamal Kumar Tumuluru|title=Hindu Prayers, Gods and Festivals|url=https://books.google.com/books?id=b2iyCAAAQBAJ&pg=PT30 |year=2015|publisher=Partridge|isbn=978-1-4828-4707-9|page=30}}</ref><ref name="Lochtefeld2002p411">{{cite book|author=James G. Lochtefeld|title=The Illustrated Encyclopedia of Hinduism: A - M|url=https://books.google.com/books?id=VNzLMgEACAAJ|year=2002|publisher=Rosen Publishing Group|isbn=978-0-8239-2287-1|page=411}}</ref>

===Iranian===
Iranian people celebrate the night of the Northern Hemisphere's winter solstice as, "Yalda night", which is known to be the "longest and darkest night of the year". Yalda night celebration, or as some call it "Shabe Chelleh" ("the 40th night"), is one of the oldest Iranian traditions that has been present in Persian culture from ancient times. In this night all the family gather together, usually at the house of the eldest, and celebrate it by eating, drinking and reciting poetry (esp. Hafez). Nuts, pomegranates and watermelons are particularly served during this festival.

===Judaic===
An Aggadic legend found in tractate Avodah Zarah 8a puts forth the talmudic hypothesis that [[Biography:Adam#Adam and the winter solstice|Adam]] first established the tradition of fasting before the [[Astronomy:Winter solstice#Judaic|winter solstice]], and rejoicing afterward, which festival later developed into the Roman Saturnalia and Kalendae.

{{blockquote|When the [[Biography:Adam|First Man]] saw that the day was continuously shortening, he said, "Woe is me! Because I have sinned, the world darkens around me, and returns to formlessless and void. This is the death to which Heaven has sentenced me!" He decided to spend eight days in fasting and prayer. When he saw the winter solstice, and he saw that the day was continuously lengthening, he said, "It is the order of the world!" He went and feasted for eight days. The following year, he feasted for both. He established them in Heaven's name, but they established them in the name of idolatry<ref>{{Cite web|title=Avodah Zarah 8a:7|url=https://www.sefaria.org/Avodah_Zarah.8a.7}}</ref>}}

== Observation ==
{{solstice-equinox}}
Although the instant of the solstice can be calculated,<ref>{{cite book|last1=Meeus|first1=Jean|title=Astronomical Algorithms|date=2009|publisher=Willmann-Bell, Inc.|location=Richmond, Virginia|isbn=978-0-943396-61-3|edition=2nd English Edition with corrections as of August 10, 2009}}</ref> direct observation of the moment by [[Philosophy:Visual perception|visual perception]] is elusive. The Sun moves too slowly or appears to stand still (the meaning of "solstice"). However, by use of [[Astronomy:Astronomy|astronomical data tracking]], the precise timing of its occurrence is now public knowledge. The precise instant of the solstice cannot be directly detected (by definition, people cannot observe that an object has stopped moving until it is later observed that it has not moved further from the preceding spot, or that it has moved in the opposite direction). To be precise to a single day, observers must be able to view a change in [[Azimuth|azimuth]] or elevation less than or equal to about 1/60 of the angular diameter of the Sun. Observing that it occurred within a two-day period is easier, requiring an observation precision of only about 1/16 of the angular diameter of the Sun. Thus, many observations are of the day of the solstice rather than the instant. This is often done by observing sunrise and sunset or using an [[Astronomy:Archaeoastronomy|astronomically aligned instrument]] that allows a ray of light to be cast on a certain point around that time. The earliest sunset and latest sunrise dates differ from winter solstice, however, and these depend on latitude, due to the variation in the solar day throughout the year caused by the Earth's elliptical orbit (see [[Astronomy:Analemma#Earliest and latest sunrise and sunset|earliest and latest sunrise and sunset]]).

==Holidays celebrated on the winter solstice==
{{div col|colwidth=25em}}
*Alban Arthan (Welsh)
*Blue Christmas (holiday) (Western Christian)
*Brumalia ([[History:Ancient Rome|Ancient Rome]])
*Dongzhi Festival ([[Place:East Asia|East Asia]])
*Inti Raymi (Inca)
*Koliada and Korochun (Slavic)
*Midwinter Day ([[Earth:Antarctica|Antarctica]])
*Sanghamitta Day ([[Philosophy:Theravada|Theravada Buddhism]])
*Shabe Yalda ([[Religion:Iran|Iran]])
*Shalako (Zuni)
*Uttarayan ({{wipe|India}})
*We Tripantu (Mapuche)
*Willkakuti (Aymara)
*Yaldā ([[Place:Western Asia|Western]] and [[Place:Central Asia|Central Asia]])
*Yule in the Northern Hemisphere (Germanic)
*Ziemassvētki (ancient Latvia)
{{div col end}}

===Other related festivals===
* Cejna Êzî/Êzîd ([[Unsolved:Yazidis|Yazidi]]): Feast of Êzîd – Celebrated on the last Friday before winter solstice
* Saturnalia ([[History:Ancient Rome|Ancient Rome]]): Celebrated shortly before winter solstice
* Saint Lucy's Day ([[Religion:Christianity|Christian]]): Used to coincide with the winter solstice day, now celebrated on December 13
* Cold Food Festival ([[Place:Korea|Korea]], [[Place:Greater China|Greater China]]): 105 days after winter solstice
* Makar Sankranti ({{wipe|India}}): Harvest Festival – Marks the end of the cold months and start of the new month with longer days.
* Winter at Tantora Festival (Saudi Arabia): Cultural festival marking the beginning of the winter harvest season.

== See also ==
{{Div col|colwidth=20em}}
* Burning the Clocks
* Christmas in July
* [[Astronomy:Effect of Sun angle on climate|Effect of Sun angle on climate]]
* Festival of Lights (disambiguation)
* [[Earth:Festive ecology|Festive ecology]]
* Festivus
* Halcyon days
* Hanukkah
* [[Philosophy:HumanLight|HumanLight]]
* [[Biology:Joss paper|Joss paper]]
* Koliada
* Kwanzaa
* Lohri
* Midsummer
* [[Astronomy:Summer solstice|Summer solstice]]
* Thai Pongal
* [[History:Tekufah|Tekufah]] 
* Tirgan
{{Div col end}}

==References==
{{Reflist}}

==Further reading==
* {{cite web | last=Macphail | first=Cameron | title=Winter solstice 2015: Everything you need to know about the shortest day of the year | website=The Daily Telegraph | date=20 December 2015 | url=https://www.telegraph.co.uk/news/science/12058397/When-is-the-winter-solstice-2015-the-shortest-day-of-the-year.html | archive-url=https://web.archive.org/web/20151218184326/http://www.telegraph.co.uk/news/science/12058397/When-is-the-winter-solstice-2015-the-shortest-day-of-the-year.html | url-status=dead | archive-date=18 December 2015 | access-date=20 December 2015}}
* {{Cite web|url = http://news.nationalgeographic.com/2015/12/151221-winter-solstice-explained-pagans|archive-url = https://web.archive.org/web/20151223235820/http://news.nationalgeographic.com/2015/12/151221-winter-solstice-explained-pagans/|url-status = dead|archive-date = December 23, 2015|title = Everything You Need to Know About the Winter Solstice|date = 2015-12-21|access-date = 2015-12-21|work =National Geographic|last = Handwerk|first = Brian}}
* {{cite web | last= Deravian | first=Naz | title=Welcoming Brighter Days on Yalda With Pomegranates | website={{wipe|The New York Times}} | date=6 December 2021 | url=https://www.nytimes.com/2021/12/06/dining/yalda-winter-solstice-pomegranate.html | archive-url=https://archive.today/20220103170951/https://www.nytimes.com/2021/12/06/dining/yalda-winter-solstice-pomegranate.html?unlocked_article_code=AAAAAAAAAAAAAAAACEIPuonUktbfqohlSlUbBSbZXN4mqBLBlPHLzLV5mX74MCWPDC1Fy_8JAoONvl_KYKdsfdI11iiWAt9dNbtlDNpD8thiBW0_AQ-5vsnD350fPyQ-rY_0UG871MvGBup9rW67MyzkIb4lge3u4k7Da2XrWqSM2Xx2J1kxsoIlIQ_xoQEAxqnFGu5w2NN0zK1hUsg8HWFcEXHM6_r4CBx-O8GEbgXe6GQ1XeJbUTLRlb2M-u5KMVUSWR-dEiQJsStr48hcOdgXIK_8MxYlHcL7irwaAWRqR5y7GaIqSwhVVkVeS9ChMTOMFA&smid=url-share | url-status=dead | archive-date=3 January 2022 | access-date=3 January 2022}}

== External links ==
* [http://www.neoprogrammics.com/sun/Northern_Winter_Dates_and_Times.html Table of times/dates from 1600–2400]


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[[Category:Astronomical events]]

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{{Sourceattribution|Winter solstice}}