spring equinox

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spring equinox

Another name for vernal equinox. See equinoxes.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Spring Equinox

Vernal Equinox

As winter melts into spring the days begin to lengthen and the nights get shorter. This process continues until, during one twenty-four-hour period, night and day are the same length. This event is known as the vernal, or spring, equinox. The word equinox comes from astronomy. It refers to those two twenty-four-hour periods in each year in which the day lasts as long as the night. Indeed, the word equinox is composed of two Latin root words meaning "equal night." In the Northern Hemisphere the equinox that occurs around March 21 heralds the arrival of spring. In the Southern Hemisphere this same day is known as the fall, or autumn, equinox and announces the beginning of autumn. In September the situation reverses itself. In the Northern Hemisphere the fall equinox arrives around September 23. This same date brings the spring equinox to the Southern Hemisphere.

Axis, Orbit, and Equinox

Scientists have determined that this slow shift in the length of earth's days and nights is caused by the tilt of the planet's axis. Each day the earth completes one full rotation on its axis, the imaginary line connecting the North and South Poles. As each continent turns to face the sun its inhabitants experience daylight, and as it turns away from the sun they experience night. All the while the earth rotates on its axis it is also moving in a long, slow, circular orbit around the sun. The earth's axis does not cross the plane of the earth's orbit around the sun at a perpendicular angle, however. Instead the earth tilts 23.5 degrees to one side. The degree and direction of this tilt remains constant as the earth orbits the sun. It takes the earth an entire year to complete its orbit around the sun.

Although the tilt of the earth remains the same, the position of the earth relative to the sun changes. In the Northern Hemisphere the winter solstice, the shortest day and longest night of the year, occurs when the earth reaches that point in its orbit in which the imaginary line connecting the earth and the sun is directly in line with the earth's axis. This gives the tilt of the earth its maximum effect on the length of the planet's days and nights because it angles the North Pole directly away from the sun and the South Pole towards it. Thus on this day people in the Northern Hemisphere experience the longest night and shortest day of the year.

As the earth continues its orbit around the sun, the days begin to lengthen. The tilt of the earth remains the same, but the path of the earth's orbit around the sun slowly moves it towards a position in which the Poles point neither towards nor away from the sun. Instead the earth's axis runs exactly parallel to the sun. When the planet reaches this position the tilt of the earth's axis has no effect on how much sunlight each region of the globe receives. During this twentyfour-hour period day and night are of equal length every place on the earth. In the equatorial zones the sun treads a path across the sky that takes it directly overhead, eliminating all shadows. In the Northern Hemisphere this day is called the spring equinox.

As the earth continues its orbit it arrives, three months later, at another location at which the earth's axis points towards the sun. This time, however, the tilt of the earth angles the North Pole towards the sun and the South Pole away from it. People in the Northern Hemisphere experience the summer solstice, the longest day and shortest night of the year, while people in the Southern Hemisphere welcome the winter solstice. Three months later the earth finds itself at the other position in its yearly orbit in which the earth's axis runs parallel to the sun. In the Northern Hemisphere the days have been getting shorter since the summer solstice. Therefore northerners experience this twentyfour-hour period of equal daylight and darkness as the autumn equinox, while southerners enjoy the arrival of the spring equinox.


Throughout history and in many different cultures people have rejoiced at the arrival of the spring equinox with its promise of light, warmth, and the renewal of nature's bounty. Holidays cluster around the date, many of which emphasize the theme of renewal. The ancient Mesopotamians established their new year festival at this time of year, which later civilizations transformed into No Ruz. The ancient Jews celebrated their release from slavery in Egypt with the Passover festival, also scheduled close to the spring equinox. The Romans observed Hilaria at this time of year, a festival commemorating the salvation of Attis, a youth devoted to the goddess Cybele. Christians observe two holy days near the spring equinox - Easter, honoring the resurrection of Jesus Christ, and the Annunciation, commemorating the Blessed Virgin Mary's conception of the Christ child.

Further Reading

Krupp, E. C. Beyond the Blue Horizon. New York: HarperCollins, 1991. Upgren, Arthur. The Night Has a Thousand Eyes: A Naked-Eye Guide to the Sky, Its Science, and Lore. New York: Plenum Press, 1998.

Web Site

"From Stargazers to Starships," a web site authored by NASA employee David P. Stern that teaches basic astronomy, physics, and the history and applications of space flight:
Encyclopedia of Easter, Carnival, and Lent, 1st ed. © Omnigraphics, Inc. 2002

Spring Equinox

(religion, spiritualism, and occult)

Many Witches call the festival at the Spring Equinox Ostara, or Eostre, after the Teutonic sun goddess Ostara and the Anglo-Saxon fertility goddess Eostre, whose name was picked up by the Christians and applied to Easter. The name may be from the same source as Astarte and Ishtar.

The days and nights are of equal length at the spring, or vernal, equinox. As with all the equinoxes and solstices, the exact date will depend upon the calendar. The twenty-first of the month is the usual date, but it can be a day or so before or after. Margaret Murray claimed that the equinoxes were never celebrated in Celtic Britain and Teutonic Europe, but today's Wiccans include them in the sabbats, making an equal division of the year.

Janet and Stewart Farrar state: "Spring was a particular season in classical and pre-classical times for a form of the sacrificial mating. . . the Hieros Gamos, or sacred marriage. In this, woman identified herself with the Goddess, and man sank himself into the Goddess through her, giving of his masculinity but not destroying it, and emerging from the experience revitalized." The Wiccan Great Rite, the Witches' hieros gamos, is therefore performed at this sabbat festival. Douglas Hill, in Man, Myth and Magic, says: "Drinking, dancing, feasting, noise-making and love-making have been the usual ways in which men have celebrated occasions of communal happiness. . . but ever since prehistoric times man has reserved special celebratory energies for the turning of the seasons and has reacted with perhaps the strongest surge of emotion to spring, the time when the earth is freed from the shackles of winter."

As with most of the sabbats, balefires were lit on the mountain tops to encourage the sun to warm the earth and bring about regeneration of the plants and trees. Also at this time many Wiccans bless seeds prior to planting them.

The Witch Book: The Encyclopedia of Witchcraft, Wicca, and Neo-paganism © 2002 Visible Ink Press®. All rights reserved.

spring equinox

[′spriŋ ′ē·kwə‚näks]
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

spring equinox

spring equinoxclick for a larger image
The point in time when there is an intersection of the ecliptic and the celestial equator (equinoctial), at which the sun is moving from a south to a north declination. The equinox occurs around March 21—the exact date varies a day or two because the number of days in a year, 365¼, contains less than a whole day. Also called the vernal equinox.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
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