Zodiac, a belt around the sky extending 9° on either side of the ecliptic, the Sun’s apparent annual path, which contains 12 constellations or astrological signs. In astrology, the outcome of an event (most notably, someone’s birth) is affected by the zodiacal positions of the Sun, the Moon, and the planets when that event happened. The orbits of the Moon and of the naked-eye planets also lie entirely within the zodiac.
The zodiac was divided into 12 astrological signs, each occupying 1/12 (or 30°) of its great circle, by the Babylonians about 500 BCE. Many of the Babylonian signs (for example, the Twins [Gemini], the Crab [Cancer], the Balance [Libra], among others) are still used today. Since most of the constellations through which the ecliptic passes represent animals, the ancient Greeks called its zone zōdiakos kyklos, “circle of animals,” or ta zōdia, “the little animals.”
###Aries,in astronomy, zodiacal constellation in the northern sky lying between Pisces and Taurus, at about 3 hours right ascension and 20° north declination.
Aries contains no very bright stars; the brightest star, Hamal (Arabic for “sheep”), has a magnitude of 2.0. The first point of Aries, or vernal equinox, is an intersection of the celestial equator with the apparent annual pathway of the Sun and the point in the sky from which celestial longitude and right ascension are measured. The vernal equinox no longer lies in Aries but has been moved into Pisces by the precession of the equinoxes.
In astrology, Aries is the first sign of the zodiac, considered as governing the period from about March 21 to about April 19. Its representation as a ram is identified with the Egyptian god Amon and, in Greek mythology, with the ram with the golden fleece, on the back of which Phrixus, the son of King Athamas, safely fled Thessaly to Colchis, where he sacrificed the ram to Zeus, who placed it in the heavens as the constellation. The ram’s golden fleece was recovered by Jason, leader of the Argonauts.
###Taurus, in astronomy, zodiacal constellation lying in the northern sky between Aries and Gemini, at about 4 hours 20 minutes right ascension and 16° north declination. The constellation’s brightest star, Aldebaran (Arabic for “the follower”; also called Alpha Tauri), is the 14th brightest star in the sky, with a magnitude of 0.85. The constellation also contains the Crab Nebula (M1) and the Pleiades and Hyades star clusters.
TaurusAstronomical chart showing a bull forming the constellation Taurus; hand-colored etching by Sidney Hall from Urania's Mirror, 1825.
TaurusTaurus (bull), watercolor and ink on paper, from a manuscript created in Ulm or Augsburg, Germany, c. 1464; in the J. Paul Getty Museum, Los Angeles.In astrology, Taurus is the second sign of the zodiac, considered as governing that portion of the year from about April 20 to about May 20. Its representation as a bull is related to the Greek myth of Zeus, who assumed the form of a bull to abduct Europa.
###Gemini, in astronomy, zodiacal constellation lying in the northern sky between Cancer and Taurus, at about 7 hours right ascension and 22° north declination. Its brightest stars are Castor and Pollux (Alpha and Beta Geminorum); Pollux is the brighter of the two, with a magnitude of 1.15, and is the 17th brightest star in the sky. The summer solstice, the northernmost point reached by the Sun in its annual apparent journey among the stars, lies in Gemini. This constellation also contains the isolated pulsar Geminga.
GeminiAstronomical chart showing the twins Castor and Pollux forming the constellation Gemini; hand-colored etching by Sidney Hall from Urania's Mirror, 1825.
GeminiGemini (twins), watercolor and ink on paper, from a manuscript created in Ulm or Augsburg, Germany, c. 1464; in the J. Paul Getty Museum, Los Angeles.In astrology, Gemini is the third sign of the zodiac, considered as governing the period from about May 21 to about June 21. It is represented by a set of twins (or in Egyptian astrology by a pair of goats and in Arabian astrology by a pair of peacocks). In addition to their identification as Castor and Pollux, the twins have also been related to other celebrated pairs, such as the younger and older Horus or Romulus and Remus.
###Cancer, in astronomy, zodiacal constellation lying in the northern sky between Leo and Gemini, at about 8 hours 25 minutes right ascension and 20° north declination. It contains the well-known star cluster called Praesepe, or the Beehive. Its brighest star, Al Tarf (Arabic for “the end” [of one of the crab’s legs]), also called Beta Cancri, is quite dim, with a magnitude of 3.6.
CancerAstronomical chart showing a crab forming the constellation Cancer; hand-colored etching by Sidney Hall from Urania's Mirror, 1825.
CancerCancer (crab), watercolor and ink, from a manuscript created in Ulm or Augsburg, Germany, c. 1464; in the J. Paul Getty Museum, Los Angeles.In astrology, Cancer is the fourth sign of the zodiac, considered as governing the period from about June 22 to about July 22. Its representation as a crab (or lobster or crayfish) is related to the crab in Greek mythology that pinched Heracles while he was fighting the Lernaean hydra. Crushed by Heracles, the crab was rewarded by Heracles’ enemy, Hera, by being placed in the heavens.
###Leo, in astronomy, zodiacal constellation lying in the northern sky between Cancer and Virgo, at about 10 hours 30 minutes right ascension and 15° north declination. Regulus (Latin for “little king”; also called Alpha Leonis), the brightest star, is of magnitude 1.35. The November meteor shower called the Leonids has its radiant, or point of apparent origin, in Leo. Many of the stars in Leo form an asterism called the Sickle.
LeoLeo (lion), watercolor and ink on paper, from a manuscript created in Ulm or Augsburg, Germany, c. 1464; in the J. Paul Getty Museum, Los Angeles.In astrology, Leo is the fifth sign of the zodiac, considered as governing the period from about July 23 to about August 22. Its representation as a lion is usually linked with the Nemean lion slain by Heracles (Hercules) as part of the 12 Labours he was forced to do as penance for killing his wife and children.
###Virgo, in astronomy, zodiacal constellation lying in the southern sky between Leo and Libra, at about 13 hours right ascension and 2° south declination. The constellation’s brightest star, Spica (Latin for “head of grain,” also called Alpha Virginis), is the 15th brightest star in the sky, with a magnitude of 1.04. Virgo contains the nearest large cluster of galaxies, the Virgo cluster, in which is located the giant elliptical galaxy Virgo A and PSR 1257+12, the pulsar around which the first extrasolar planets were discovered in 1992.
VirgoVirgo (virgin), watercolor and ink on paper, from a manuscript created in Ulm or Augsburg, Germany, c. 1464; in the J. Paul Getty Museum, Los Angeles.In astrology, Virgo is the sixth sign of the zodiac, considered as governing the period from about August 23 to about September 22. It is represented as a young maiden carrying a sheaf of wheat. She is variously identified as a fertility goddess (the Babylonian and Assyrian Ishtar, among others) or the harvest maiden (the Greek Persephone and others).
###Libra, in astronomy, zodiacal constellation in the southern sky lying between Scorpius and Virgo, at about 15 hours 30 minutes right ascension and 15° south declination. Its stars are faint; the brightest star, Zubeneschamali (Arabic for “northern claw,” as it was earlier regarded as part of Scorpius; also called Beta Librae), has a magnitude of 2.6.
LibraLibra (balance), watercolor and ink on paper, from a manuscript created in Ulm or Augsburg, Germany, c. 1464; in the J. Paul Getty Museum, Los Angeles.In astrology, Libra is the seventh sign of the zodiac, considered as governing the period from about September 22 to about October 23. It is represented by a woman (sometimes identified with Astraea, the Roman goddess of justice), holding a balance scale or by the balance alone.