History and mythology
Aries is now recognized as an official constellation, albeit as a specific region of the sky, by the International Astronomical Union. It was originally defined in ancient texts as a specific pattern of stars, and has remained a constellation since ancient times; it now includes the ancient pattern as well as the surrounding stars. In the description of the Babylonian zodiac given in the clay tablets known as the MUL.APIN, the constellation now known as Aries was the final station along the ecliptic. The MUL.APIN was a comprehensive table of the risings and settings of stars, which likely served as an agricultural calendar. Modern-day Aries was known as MULLÚ.ḪUN.GÁ, "The Agrarian Worker" or "The Hired Man". Although likely compiled in the 12th or 11th century BC, the MUL.APIN reflects a tradition which marks the Pleiades as the vernal equinox, which was the case with some precision at the beginning of the Middle Bronze Age. The earliest identifiable reference to Aries as a distinct constellation comes from the boundary stones that date from 1350 to 1000 BC. On several boundary stones, a zodiacal ram figure is distinct from the other characters present. The shift in identification from the constellation as the Agrarian Worker to the Ram likely occurred in later Babylonian tradition because of its growing association with Dumuzi the Shepherd. By the time the MUL.APIN was created—by 1000 BC—modern Aries was identified with both Dumuzi's ram and a hired laborer. The exact timing of this shift is difficult to determine due to the lack of images of Aries or other ram figures.
In ancient Egyptian astronomy, Aries was associated with the god Amon-Ra, who was depicted as a man with a ram's head and represented fertility and creativity. Because it was the location of the vernal equinox, it was called the "Indicator of the Reborn Sun". During the times of the year when Aries was prominent, priests would process statues of Amon-Ra to temples, a practice that was modified by
Persian astronomers centuries later. Aries acquired the title of "Lord of the Head" in Egypt, referring to its symbolic and mythological importance.
Aries depicted in an early medieval manuscript, c.1000
Aries was not fully accepted as a constellation until classical times. In Hellenistic astrology, the constellation of Aries is associated with the golden ram of Greek mythology that rescued Phrixus and Helle on orders from Hermes, taking Phrixus to the land of Colchis. Phrixos and Helle were the son and daughter of King Athamas and his first wife Nephele. The king's second wife, Ino, was jealous and wished to kill his children. To accomplish this, she induced a famine in Boeotia, then falsified a message from the Oracle of Delphi that said Phrixos must be sacrificed to end the famine. Athamas was about to sacrifice his son atop
Mount Laphystium when Aries, sent by Nephele, arrived. Helle fell off of Aries's back in flight and drowned in the Dardanelles, also called the Hellespont in her honor. After arriving, Phrixus sacrificed the ram to Zeus and gave the Fleece to Aeëtes of Colchis, who rewarded him with an engagement to his daughter Chalciope. Aeëtes hung its skin in a sacred place where it became known as the Golden Fleece and was guarded by a dragon. In a later myth, this Golden Fleece was stolen by Jason and the Argonauts.
Historically, Aries has been depicted as a crouched, wingless ram with its head turned towards Taurus. Ptolemy asserted in his Almagest that Hipparchus depicted Alpha Arietis as the ram's muzzle, though Ptolemy did not include it in his constellation figure. Instead, it was listed as an "unformed star", and denoted as "the star over the head". John Flamsteed, in his Atlas Coelestis, followed Ptolemy's description by mapping it above the figure's head. Flamsteed followed the general convention of maps by depicting Aries lying down. Astrologically, Aries has been associated with the head and its humors. It was strongly associated with Mars, both the planet and the god. It was considered to govern Western Europe and Syria, and to indicate a strong temper in a person.
The First Point of Aries, the location of the vernal equinox, is named for the constellation. This is because the Sun crossed the celestial equator from south to north in Aries more than two millennia ago. Hipparchus defined it in 130 BC. as a point south of Gamma Arietis. Because of the precession of the equinoxes, the First Point of Aries has since moved into Pisces and will move into Aquarius by around 2600 AD. The Sun now appears in Aries from late April through mid May, though the constellation is still associated with the beginning of spring.
Medieval Muslim astronomers depicted Aries in various ways. Astronomers like al-Sufi saw the constellation as a ram, modeled on the precedent of Ptolemy. However, some Islamic celestial globes depicted Aries as a nondescript four-legged animal with what may be antlers instead of horns. Some early Bedouin observers saw a ram elsewhere in the sky; this constellation featured the Pleiades as the ram's tail. The generally accepted Arabic formation of Aries consisted of thirteen stars in a figure along with five "unformed" stars, four of which were over the animal's hindquarters and one of which was the disputed star over Aries's head. Al-Sufi's depiction differed from both other Arab astronomers' and Flamsteed's, in that his Aries was running and looking behind itself.
The obsolete constellations introduced in Aries (Musca Borealis, Lilium, Vespa, and Apes) have all been composed of the northern stars. Musca Borealis was created from the stars 33 Arietis, 35 Arietis, 39 Arietis, and 41 Arietis. In 1612, Petrus Plancius introduced Apes, a constellation representing a bee. In 1624, the same stars were used by Jakob Bartsch to create a constellation called Vespa, representing a wasp. In 1679 Augustin Royer used these stars for his constellation Lilium, representing the fleur-de-lis. None of these constellation became widely accepted. Johann Hevelius renamed the constellation "Musca" in 1690 in his
Firmamentum Sobiescianum. To differentiate it from Musca, the southern fly, it was later renamed Musca Borealis but it did not gain acceptance and its stars were ultimately officially reabsorbed into Aries.
In 1922, the International Astronomical Union defined its recommended three-letter abbreviation, "Ari". The official boundaries of Aries were defined in 1930 by Eugène Delporte as a polygon of 12 segments. Its right ascension is between 1h 46.4m and 3h 29.4m and its declination is between 10.36° and 31.22° in the equatorial coordinate system.
In non-Western astronomy
In traditional Chinese astronomy, stars from Aries were used in several constellations. The brightest stars—Alpha, Beta, and Gamma Arietis—formed a constellation called Lou, variously translated as "bond", "lasso", and "sickle", which was associated with the ritual sacrifice of cattle. This name was shared by the 16th lunar mansion, the location of the full moon closest to the autumnal equinox. The lunar mansion represented the area where animals were gathered before sacrifice around that time. This constellation has also been associated with harvest-time as it could represent a woman carrying a basket of food on her head. 35, 39, and 41 Arietis were part of a constellation called Wei, which represented a fat abdomen and was the namesake of the 17th lunar mansion, which represented granaries. Delta and Zeta Arietis were a part of the constellation Tianyin, thought to represent the Emperor's hunting partner. Zuogeng (Tso-kang), a constellation depicting a marsh and pond inspector, was composed of Mu, Nu, Omicron, Pi, and Sigma Arietis. He was accompanied by Yeou-kang, a constellation depicting an official in charge of pasture distribution.
In a similar system to the Chinese, the first lunar mansion in Hindu astronomy was called "Aswini", after the traditional names for Beta and Gamma Arietis, the Aswins. Because the Hindu new year began with the vernal equinox, the Rig Veda contains over 50 new-year's related hymns to the twins, making them some of the most prominent characters in the work. Aries itself was known as "Aja" and "Mesha". In Hebrew astronomy Aries was named "Teli"; it signified either Simeon or Gad, and generally symbolizes the "Lamb of the World". The neighboring Syrians named the constellation "Amru", and the bordering Turks named it "Kuzi". Half a world away, in the Marshall Islands, several stars from Aries were incorporated into a constellation depicting a porpoise, along with stars from Cassiopeia, Andromeda, and Triangulum. Alpha, Beta, and Gamma Arietis formed the head of the porpoise, while stars from Andromeda formed the body and the bright stars of Cassiopeia formed the tail. Other Polynesian peoples recognized Aries as a constellation. The Marquesas islanders called it Na-pai-ka; the Māori constellation Pipiri may correspond to modern Aries as well. In indigenous Peruvian astronomy, a constellation with most of the same stars as Aries existed. It was called the "Market Moon" and the "Kneeling Terrace", as a reminder for when to hold the annual harvest festival,