March equinox

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The March equinox [1] [2] or northward equinox [3] is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the vernal equinox (or spring equinox) in the Northern Hemisphere and as the autumnal equinox (or fall equinox) in the Southern Hemisphere. [2] [1] [4]

Contents

Illumination of Earth by the Sun on the day of an equinox Earth-lighting-equinox EN.png
Illumination of Earth by the Sun on the day of an equinox
UT date and time of
equinoxes and solstices on Earth [5] [6]
event equinox solstice equinox solstice
monthMarch [7] June [8] September [9] December [10]
yeardaytimedaytimedaytimedaytime
20202003:502021:432213:312110:03
20212009:372103:322219:212115:59
20222015:332109:142301:042121:48
20232021:252114:582306:502203:28
20242003:072020:512212:442109:20
20252009:012102:422218:202115:03
20262014:462108:252300:062120:50
20272020:252114:112306:022202:43
20282002:172020:022211:452108:20
20292008:012101:482217:372114:14
20302013:512107:312223:272120:09

On the Gregorian calendar at 0° longitude, the northward equinox usually occurs on March 20. However, it can occur as early as March 19 (which happened most recently in 1796, and will happen next in 2044), and it can occur as late as March 21 (which happened most recently in 2007, and will happen next in 2102). For a common year the computed time slippage is about 5 hours 49 minutes later than the previous year, and for a leap year about 18 hours 11 minutes earlier than the previous year. Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from March 20 each year.

The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere but marks the beginning of astronomical autumn and the end of astronomical summer in the Southern Hemisphere. [11]

In astronomy, the March equinox is the zero point of sidereal time and, consequently, the right ascension and ecliptic longitude. [12] It also serves as a reference for calendars and celebrations in many cultures and religions.

Constellation

The point where the Sun crosses the celestial equator northwards is called the First Point of Aries. However, due to the precession of the equinoxes, this point is no longer in the constellation Aries, but rather in Pisces. [13] By the year 2600 it will be in Aquarius. The Earth's axis causes the First Point of Aries to travel westwards across the sky at a rate of roughly one degree every 72 years. Based on the modern constellation boundaries, the northward equinox passed from Taurus into Aries in the year −1865 (1866 BC), passed into Pisces in the year −67 (68 BC), will pass into Aquarius in the year 2597, and will pass into Capricornus in the year 4312. It passed by (but not into) a 'corner' of Cetus at 0°10′ distance in the year 1489.[ citation needed ]

Apparent movement of the Sun

In its apparent motion on the day of an equinox, the Sun's disk crosses the Earth's horizon directly to the east at sunrise; and again, some 12 hours later, directly to the west at sunset. The March equinox, like all equinoxes, is characterized by having an almost exactly equal amount of daylight and night across most latitudes on Earth. [14]

Culture

Calendars

The Babylonian calendar began with the first new moon after the March equinox, the day after the return of the Sumerian goddess Inanna (later known as Ishtar) from the underworld, in the Akitu ceremony, with parades through the Ishtar Gate to the Eanna temple and the ritual re-enactment of the marriage to Tammuz, or Sumerian Dummuzi.[ citation needed ]

The Persian calendar begins each year at the northward equinox, observationally determined at Tehran. [15]

The Indian national calendar starts the year on the day next to the vernal equinox on March 22 (March 21 during leap years) with a 30-day month (31 days in leap years), then has 5 months of 31 days followed by 6 months of 30 days. [15]

Julian calendar

The Julian calendar reform lengthened seven months and replaced the intercalary month with an intercalary day to be added every four years to February. It was based on a length for the year of 365 days and 6 hours (365.25 d), while the mean tropical year is about 11 minutes and 15 seconds less than that. This had the effect of adding about three quarters of an hour every four years. The effect accumulated from inception in 45 BC and by the 16th century, the northern vernal equinox fell on March 10 or 11. [16] Since the date of the equinox is critical to calculation of the date of Easter, its drift from astronomical reality was of grave concern to the Catholic church. It was for this reason that the Gregorian calendar reform was introduced in 1582, to reinstate the date to about 21 March and to minimise any further drifting. Since 1900, the calendars differ by 13 days: from 1 March 2100, the difference will become 14 days.

Commemorations

Bas-relief in Persepolis, a symbol of Iranian Nowruz: a bull (symbolizing the Earth) and lion (the Sun) in eternal combat are equal in power on the equinox. Nowruz Zoroastrian.jpg
Bas-relief in Persepolis, a symbol of Iranian Nowruz: a bull (symbolizing the Earth) and lion (the Sun) in eternal combat are equal in power on the equinox.
Chichen Itza during the spring equinox--Kukulkan, the famous descent of the snake ChichenItzaEquinox.jpg
Chichen Itza during the spring equinox—Kukulkan, the famous descent of the snake

Abrahamic tradition

  • The Jewish Passover usually falls on the first full moon after the Northern Hemisphere vernal equinox, [17] although occasionally (currently three times every 19 years[ citation needed ]) it will occur on the second full moon. [18]
  • The Christian Churches calculate Easter as the first Sunday after the first full moon on or after the March equinox. The official church definition for the equinox is March 21. The Eastern Orthodox Churches use the older Julian calendar, while the western churches use the Gregorian calendar, and the western full moons currently fall four, five or 34 days before the eastern ones. The result is that the two Easters generally fall on different days but they sometimes coincide. The earliest possible western Easter date in any year is March 22 on each calendar. The latest possible western Easter date in any year is April 25. [19]

Iranian tradition

  • The northward equinox marks the first day of various calendars including the Iranian calendar. The ancient Iranian peoples' new year's festival of Nowruz can be celebrated March 20 or March 21. According to the ancient Persian mythology Jamshid, the mythological king of Persia, ascended to the throne on this day and each year this is commemorated with festivities for two weeks. Along with Iranian peoples, it is also a holiday celebrated by Turkic people, the North Caucasus and in Albania. It is also a holiday for Zoroastrians, adherents of the Baháʼí Faith and Nizari Ismaili Muslims irrespective of ethnicity. [20]

West Asia and North Africa

South and Southeast Asia

According to the sidereal solar calendar, celebrations which originally coincided with the March equinox now take place throughout South Asia and parts of Southeast Asia on the day when the Sun enters the sidereal Aries, generally around April 14.

East Asia

  • The traditional East Asian calendars divide a year into 24 solar terms (节气, literally "climatic segments"), and the vernal equinox ( Chūnfēn , Chinese and Japanese : 春分; Korean : 춘분; Vietnamese : Xuân phân) marks the middle of the spring. In this context, the Chinese character 分 means "(equal) division" (within a season).
  • In Japan, Vernal Equinox Day (春分の日 Shunbun no hi) is an official national holiday, and is spent visiting family graves and holding family reunions. [21] [22] Higan (お彼岸) is a Buddhist holiday exclusively celebrated by Japanese sects during both the Spring and Autumnal Equinox. [21]

Europe

Equinox at the site of Pizzo Vento, Fondachelli Fantina, Sicily Equinozio da Pizzo Vento,tramonto fondachelli fantina, sicilia.JPG
Equinox at the site of Pizzo Vento, Fondachelli Fantina, Sicily

The Americas

Modern culture

See also

References

  1. 1 2 Serway, Raymond; Jewett, John (January 8, 2013). Physics for Scientists and Engineers. Cengage Learning. p. 409. ISBN   978-1-285-53187-8.
  2. 1 2 United States Naval Training Command (1972). Navigation compendium. U.S. Govt. Print. Off. p. 88.
  3. ↑ "Embracing the Equinox". Night Sky Network. Jet Propulsion Laboratory. February 18, 2022. Retrieved July 19, 2022.
  4. ↑ Desonie, Dana (2008). Polar Regions: Human Impacts. Infobase Publishing. p. 6. ISBN   978-1-4381-0569-7.
  5. ↑ Astronomical Applications Department of USNO. "Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion" . Retrieved August 1, 2022.
  6. ↑ "Solstices and Equinoxes: 2001 to 2100". AstroPixels.com. February 20, 2018. Retrieved December 21, 2018.
  7. ↑ Équinoxe de printemps entre 1583 et 2999
  8. ↑ Solstice d’été de 1583 à 2999
  9. ↑ Équinoxe d’automne de 1583 à 2999
  10. ↑ Solstice d’hiver
  11. ↑ "Defining Seasons". timeanddate.com.
  12. ↑ Zeilik, M.; Gregory, S. A. (1998). Introductory Astronomy & Astrophysics (4th ed.). Saunders College Publishing. p. 36. ISBN   0030062284.
  13. ↑ Spherical Astronomy. Krishna Prakashan Media. pp. 233ff. GGKEY:RDRHQ35FBX7.
  14. ↑ Resnick, Brian (March 19, 2020). "The spring equinox is Thursday: 8 things to know about the first day of spring". Vox. Retrieved March 20, 2020.
  15. 1 2 Bromberg, Irv. "The Lengths of the Seasons". University of Toronto, Canada. Retrieved July 6, 2013.
  16. ↑ Blackburn, Bonnie; Holford-Strevens, Leofranc (2003). The Oxford companion to the Year: An exploration of calendar customs and time-reckoning . Oxford University Press. p.  683. ISBN   0-19-214231-3. Corrected reprinting of original 1999 edition.
  17. ↑ Burnaby, Sherrard Beaumont (1901). "Elements of the Jewish and Muhammedan calendars with rules and tables and explanatory notes on the Julian and Gregorian calendars". London. pp. 13–14.
  18. ↑ Burnaby, Sherrard Beaumont (1901). "Elements of the Jewish and Muhammedan calendars with rules and tables and explanatory notes on the Julian and Gregorian calendars". London. pp. 9–10.
  19. ↑ Cooley, Keith (2001). "Keith's Moon Facts". Hiwaay.net personal pages. Archived from the original on December 3, 2010. Retrieved April 7, 2012.[ self-published source ]
  20. ↑ "Navroz". The Ismaili. Islamic Publications Limited. Retrieved July 4, 2011.
  21. 1 2 Milton Walter Meyer (1993). Japan: A Concise History . Rowman & Littlefield. pp.  246. ISBN   978-0-8226-3018-0.
  22. ↑ Yoneyuki Sugita (August 18, 2016). Social Commentary on State and Society in Modern Japan. Springer. p. 23. ISBN   978-981-10-2395-8.
  23. ↑ "Disablót". Nationalencyklopedin (in Swedish).
  24. ↑ "Visitors Guide to the Woodhenge". January 8, 2019. Retrieved December 21, 2019.
  25. ↑ Iseminger, William. "Welcome the Fall Equinox at Cahokia Mounds". Illinois Department of Natural Resources. Archived from the original on December 22, 2017. Retrieved December 20, 2017.
  26. ↑ "Winter Solstice Sunrise Observance at Cahokia Mounds". Collinsville Chamber of Commerce. Retrieved December 20, 2017.
  27. ↑ "Cahokia Mounds Mark Spring Equinox : The keepers of Cahokia Mounds will host a spring gathering to celebrate the vernal equinox". Indian Country Today. Indian Country Media Network. Archived from the original on December 22, 2017. Retrieved December 20, 2017.
  28. ↑ "World Citizens Day—World Unity Day". Consultative Assembly of the Peoples Congress. 2007.
  29. ↑ "With Spring comes the Baháʼí New Year". National Spiritual Assembly of the Baháʼís of the United States. Archived from the original on September 28, 2011. Retrieved July 4, 2011.
  30. ↑ Wyatt, Kristen. "Annapolis Welcomes Spring by Burning Socks". Associated Press . Annapolis, Maryland. Retrieved February 15, 2022.
  31. ↑ Rey, Diane. "Hillsmere Joins in Sock Burning Tradition". The Capital . Annapolis, Maryland. Retrieved April 25, 2011.
  32. ↑ Gander, Kashmira (March 20, 2014). "Spring equinox 2014: First day of spring marked by Google Doodle". The Independent. London. Retrieved March 20, 2014.
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