Description

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Context

Vernal Equinox occurring on March 20, 2025 marks key celestial event when sun appears directly above Equator leading to equal day & night durations globally & influencing numerous cultural & religious celebrations.

Key Highlights

Vernal Equinox marks start of spring in Northern Hemisphere & autumn in Southern Hemisphere.

It occurs when Sun appears directly above Equator at noon resulting in nearly equal durations of day & night across globe.

The term equinox originates from Latin words aequus (equal) & nox (night).

The 2025 Vernal Equinox occurs on March 20.

Equinoxes happen twice a year in March (Vernal Equinox) & September (Autumnal Equinox).

Equal day & night: On this day Earth axis is neither tilted towards nor away from Sun leading to equal sunlight distribution across both hemispheres.

The Sun rises exactly in East & sets exactly in West.

Difference Between Equinox & Solstice:

Feature	Equinox (March & September)	Solstice (June & December)
Sun’s Position	Directly over Equator	Maximum tilt towards/away from Sun
Day & Night	Almost equal everywhere	Longest/shortest day depending on hemisphere
Earth’s Tilt	No tilt effect on sunlight	Extreme tilt effect
Seasons Begin	Spring & Autumn	Summer & Winter

Cultural & Religious Significance:

Many civilizations have used Vernal Equinox to mark new year & religious festivals.

Persian New Year (Nowruz): Celebrated by Zoroastrians & Parsi community Nowruz is based on solar calendar & starts with spring equinox.

Easter (Christianity): The date of Easter is calculated based on first full moon after equinox.

Passover (Judaism): Starts on first full moon after March equinox.

Vernal Equinox Day (Japan): A national holiday celebrating renewal & balance.

Chuseok (Korea): A harvest festival related to autumn equinox.

Scientific & Environmental Impact:

Weather Transition: Northern Hemisphere shifts to warmer temperatures as it starts tilting toward Sun. Southern Hemisphere moves into cooler autumn conditions.

Impact on Ecosystem: Migration of birds & animals adjusts to changing season. Flowering & crop cycles begin with increased daylight.

Historical Observations of Equinox:

Ancient Babylonian Calendar: Based on lunar cycles following equinox.

Mayan Civilization: Chichen Itza pyramid in Mexico is aligned to equinox creating a serpent-like shadow.

Stonehenge, UK: A prehistoric monument aligned with solar & equinox positions.

Equinoxes & Solstices

Aspect	Vernal (Spring) Equinox	Autumnal (Fall) Equinox	Summer Solstice	Winter Solstice
Date (Northern Hemisphere)	March 19-21	September 21-24	June 20-22	December 20-23
Date (Southern Hemisphere)	September 21-24	March 19-21	December 20-23	June 20-22
Sun's Position	Directly over Equator	Directly over Equator	Directly over Tropic of Cancer (23.5° N)	Directly over Tropic of Capricorn (23.5° S)
Day & Night Duration	Equal (12 hours each)	Equal (12 hours each)	Longest day, shortest night (NH)	Shortest day, longest night (NH)
Earth’s Axis Tilt Effect	No tilt effect	No tilt effect	Maximum tilt towards Sun in NH	Maximum tilt away from Sun in NH
Season in Northern Hemisphere	Start of spring	Start of autumn (fall)	Start of summer	Start of winter
Season in Southern Hemisphere	Start of autumn (fall)	Start of spring	Start of winter	Start of summer
Cultural & Religious Significance	Nowruz (Persian New Year), Easter, Passover, Vernal Equinox Day (Japan)	Chuseok (Korea), Jewish Rosh Hashanah & Yom Kippur, Harvest Festivals	Midsummer festivals, Inti Raymi (Inca Festival of Sun)	Christmas, Dongzhi Festival (China), Yule (Pagan Festival)
Impact on Ecosystem	Migration of birds, flowering of plants	Animals preparing for winter, harvest season	Peak growth period for plants	Dormancy of plants, hibernation of animals
Scientific Importance	Day & night are equal worldwide	Day & night are equal worldwide	Longest daylight duration in NH	Shortest daylight duration in NH
Historical Observations	Chichen Itza pyramid alignment (Maya civilization), Stonehenge solar alignment (UK)	Celestial alignments in ancient cultures	Ancient Egyptian & Greek Sun worship festivals	Ancient Scandinavian Yule celebrations

Festivals Associated with Equinoxes & Solstices

Festival	Region/Culture	Associated Event	Description
Nowruz	Persia (Iran, Central Asia, Zoroastrianism)	Spring Equinox (March 20-21)	Persian New Year, celebrated with fire-jumping, feasting & family gatherings.
Vernal Equinox Day (Shunbun no Hi)	Japan	Spring Equinox (March 20-21)	A national holiday honoring nature & family ancestors.
Easter	Christianity	Spring Equinox-based (March-April)	Celebrated on first Sunday after full moon following equinox, marking Christ’s resurrection.
Passover (Pesach)	Judaism	Spring Equinox-based (March-April)	Commemorates Israelites’ exodus from Egypt, beginning on first full moon after equinox.
Holi	India	Spring Equinox-based (March)	Festival of colors marking arrival of spring & victory of good over evil.
Chichen Itza’s Serpent Shadow Festival	Mayan Civilization (Mexico)	Spring & Autumn Equinox (March & Sept)	Sunlight creates a snake-like shadow on El Castillo pyramid, a sacred Mayan site.
Alban Eilir	Celtic/Druidic	Spring Equinox (March 20-21)	Ancient Druidic festival celebrating renewal, fertility & balance in nature.
Chuseok	Korea	Autumn Equinox (Sept 21-24)	Korean harvest festival with feasting, ancestor worship & traditional games.
Rosh Hashanah	Judaism	Autumn Equinox-based (Sept-Oct)	Jewish New Year, calculated 163 days after Passover, marked by prayer & festive meals.
Yom Kippur	Judaism	Autumn Equinox-based (Sept-Oct)	"Day of Atonement," observed with fasting, prayer & repentance.
Mid-Autumn Festival (Moon Festival)	China, Vietnam	Autumn Equinox (Sept 21-24)	Celebrates full moon, harvest & family gatherings with mooncakes & lanterns.
Harvest Home / Mabon	Celtic/Druidic	Autumn Equinox (Sept 21-24)	Pagan harvest festival marking balance between light & darkness.
Stonehenge Summer Solstice Festival	United Kingdom	Summer Solstice (June 20-22)	Thousands gather at Stonehenge to celebrate longest day with druidic & pagan traditions.
Inti Raymi (Festival of Sun)	Inca Civilization (Peru)	Winter Solstice (June 20-22, Southern Hemisphere)	Incan festival honoring Sun God Inti, featuring rituals, feasting & music.
Midsummer (Juhannus, St. John’s Day)	Finland, Sweden, Northern Europe	Summer Solstice (June 20-22)	Bonfires, dancing & nature celebrations mark longest day of year.
Kupala Night	Slavic Regions (Ukraine, Russia, Poland)	Summer Solstice (June 20-22)	Pagan festival celebrating fertility, love & nature with water & fire rituals.
Litha	Pagan/Wiccan	Summer Solstice (June 20-22)	Festival celebrating peak of sunlight with bonfires & nature worship.
Feast of John Baptist	Christian (Spain, Brazil, Portugal)	Summer Solstice-based (June 23-24)	Religious festival featuring parades, bonfires & water blessings.
Dongzhi Festival	China	Winter Solstice (Dec 21-23)	Celebrates return of longer daylight with family gatherings & dumpling feasts.
Yule	Pagan/European Traditions	Winter Solstice (Dec 20-23)	An ancient festival celebrating rebirth of sun, later influencing Christmas traditions.
Soyal	Hopi Tribe (Native American)	Winter Solstice (Dec 21-22)	Ceremonial dances & rituals to welcome return of sun & bless community.
Lohri	India (Punjab, North India)	Winter Solstice-based (Jan 13-14)	Celebrates end of winter with bonfires, folk music & sweets.
Makar Sankranti	India	Winter Solstice-based (Jan 14-15)	Marks Sun’s transition into Capricorn & northward movement (Uttarayan), celebrated with kite flying & feasts.
Shab-e Yalda	Persia/Iran	Winter Solstice (Dec 20-21)	Persian festival marking longest night of year, featuring poetry recitals & eating pomegranates.

For more information, please refer to IAS GYAN

Sources:

INDIAN EXPRESS

PRACTICE QUESTION

Q. Discuss astronomical phenomena of equinoxes & solstices & their impact on seasonal changes. How have different civilizations historically interpreted & celebrated these events? Illustrate with examples.