March equinox

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The March equinox^[7][8] or northward equinox^[9] 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 (spring equinox) in the Northern Hemisphere and as the autumnal equinox (autumn equinox or fall equinox) in the Southern Hemisphere.^[8][7][10]

On the Gregorian calendar, the northward equinox can occur as early as 19 March or as late as 21 March at 0° longitude. 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 20 March each year.

The March equinox may be taken to mark the beginning of

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

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

The Indian national calendar starts the year on the day next to the vernal equinox on 22 March (21 March in 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 until the 16th century, when the northern vernal equinox fell on 10 or 11 March.^[16]

The date in 1452 was 11 March, 11:52 (Julian).^[17] In 2547 it will be 20 March, 21:18 (Gregorian) and 3 March, 21:18 (Julian).^[18]

Commemorations

Abrahamic tradition

• The Jewish Passover usually falls on the first full moon after the Northern Hemisphere vernal equinox,^[19] although occasionally (currently three times every 19 years^{[citation needed]}) it will occur on the second full moon.^[20]
• The
  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 21 March. 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 22 March on each calendar. The latest possible western Easter date in any year is 25 April.^[21]

• The northward equinox marks the first day of various calendars including the
  Nizari Ismaili Muslims irrespective of ethnicity.^[22]

• In many
  Arab countries, Mother's Day is celebrated on the northward equinox.^{[citation needed}
  ]
• Sham el-Nessim is a modern celebration which is claimed by some to have been celebrated in ancient Egypt but with little evidence. It is one of the public holidays in Egypt. It is assumed by some that sometime during Egypt's Christian period (c. 200–639) the date moved to Easter Monday, but before then it coincided with the vernal equinox.^{[citation needed}
  ]

• In Cambodia, the Angkor Wat Equinox is a solar phenomenon which dates back to the reign of Suryavarman II.

East Asia

• The traditional East Asian calendars divide a year into 24
  Chinese character
  分 means "(equal) division" (within a season).
• In Japan,
  national holiday, and is spent visiting family graves and holding family reunions.^[23][24] Higan (お彼岸) is a Buddhist holiday exclusively celebrated by Japanese sects during both the Spring and Autumnal Equinox.^[23]

• Hilaria was an ancient Roman festival commemorating the death and resurrection of Attis.
• Lieldienas
• in
  Norse paganism, a Dísablót was celebrated on the vernal equinox.^[25]
• Drowning of Marzanna

• Spring equinox in Teotihuacán
• The reconstructed Cahokia Woodhenge, a large timber circle located at the Mississippian culture Cahokia archaeological site near Collinsville, Illinois,^[26] is the site of annual equinox and solstice sunrise observances. Out of respect for Native American beliefs these events do not feature ceremonies or rituals of any kind.^[27][28][29]

Modern culture

• World Storytelling Day is a global celebration of the art of oral storytelling, celebrated every year on the day of the northward equinox.^{[citation needed]}
• World Citizen Day occurs on the northward equinox.^[30]
• The Baháʼí calendar year starts at the sunset preceding the March equinox calculated for Tehran.^[31]
• In Annapolis, Maryland, United States, boatyard employees and sailboat owners celebrate the spring equinox with the "Burning of the Socks" festival. Traditionally, the boating community wears socks only during the winter. These are burned at the approach of warmer weather, which brings more customers and work to the area. Officially, nobody then wears socks until the next equinox.^[32][33]
• Ostara) as a cardinal point on the Wheel of the Year. In the northern hemisphere some varieties of paganism adapt vernal equinox celebrations, while in the southern hemisphere pagans adapt autumnal traditions.^{[citation needed}
  ]
• International Astrology Day^{[citation needed]}
• On 20 March 2014 and 20 March 2018, the March equinox was commemorated by an animated Google Doodle.^[34]

See also

References