Greek Mythology and Constellations ---------------------------------- Copyright 2003, by F. A. Ringwald Published in Amateur Astronomy magazine, Volume 40, December 2003. In 1930, the International Astronomical Union divided the entire sky into 88 constellations. Many in the Southern Hemisphere were named in the 1600s, and reflect scientific interests of the time. These include Telescopium the telescope, Microscopium the microscope, Fornax the furnace, Sextans the sextant, Octans the octant (a navigational instrument made obsolete by the sextant), and Antlia the air pump. That's right, Antlia the air pump: at the time, the air pump was a major scientific instrument, since one could make a vacuum with one---and this directly contradicted Aristotle, who taught that "Nature abhors a vacuum." Many constellations in the Northern Hemisphere were named in ancient times, and have names from Greek and Roman mythology. That the IAU adopted Greek and Roman constellations in no way means that the Greeks and the Romans were the only people to make up constellations. Nearly all cultures do, since the patterns make the stars easier to identify, and therefore more useful for timekeeping, essential for agriculture. For example, Ursa Major is the Greek constellation the Great Bear. In America, it is known a the Big Dipper. In England, it is known at the Plough, or Charles's Wain, the wagon of King Charles. In China, it is the carriage. It is therefore pointless to argue about constellations: for all of them, someone has "another story." Indeed, even the "official" Greek ones, adopted by the IAU, are based mostly on Greek myths, which were told around campfires for centuries before they were written down by the Latin poet Ovid, in the first century A.D. Even for them, therefore, there are always alternative ways that many stories come out: in the same way the children's game "telephone" can change stories, when repeated person to person, myths and legends will change, being based on an oral tradition. In addition to constellation patterns on the sky, there are asterisms. Asterisms aren't official constellations: they're simple geometric patterns, usually only of the brightest stars, that serve as useful guides to finding the constellations. A famous asterism visible in summer in the Northern Hemisphere is the Summer Triangle. In fall one can see the Great Square of Pegasus. In winter one can see "the heavenly G", a large G-shaped group of constellations around Orion. The two stars at the end of the bowl of the Big Dipper can be used to find Polaris, the North Star. Polaris is special only because by coincidence, it is close to the North Celestial Pole. It therefore always appears due north of any observer who can see it above the horizon, in the Northern Hemisphere. It is by no means the brightest star in the sky: this really is a myth. Orion, the hunter, is a striking constellation, with many bright stars, particularly three bright stars in a row, the belt of Orion. Opposite the sky is Scorpius the Scorpion, who stung Orion to death. Next to Scorpius is Ophiuchus, the snake bearer---or the doctor, since Asclepius, the greatest of physicians in Greek mythology, learned all his art and all the secrets of the Earth from a snake, whose mother he gave a proper funeral. Gemini, the twins, is another winter constellation, next to Orion. In it are two first-magnitude stars, Castor and Pollux. In Greek mythology, Castor and Pollux were twin brothers, of Zeus and Leda, a mortal. Pollux was immortal, but Castor was not. The brothers loved each other so, that Pollux gave Castor half of his immortality---meaning that, when they died, they became the constellation. To the south and west of Orion are his two hunting dogs, the constellations Canis Major and Canis Minor. Canis Major has Sirius, the brightest star in the nighttime sky. Canus Minor has first-magnitude Procyon. To the north of Orion is the constellation Auriga, the charioteer, with the first magnitude star, Capella. To the northeast of Orion, south of Auriga, is the constellation Taurus, the bull. Orion is shown fighting him, with his great club raised. His shield is an arc of faint stars, warding off the bull's attack. Centaurus is too far south to be easily visible from mid-northern latitudes. This is too bad, because it is a large and spectacular constellation, rivaling Orion in splendor and in number and diversity of astrophysically interesting objects. Its has two first-magnitude stars, Alpha Centauri and Beta Centauri; nowhere else in the sky are two stars this bright that close to each other. In Greek mythology, the Centaurs were wild, uncouth, destructive creatures---except for Chiron, who was kind and wise, and who educated young heroes before they would go out and do their famous deeds. A prominent spring constellation is Ursa Major, the great bear. In America, it is often referred to at the Big Dipper, with seven bright, second-magnitude stars tracing the shape of a dipper. In Greek mythology, the bear was Callisto, a lover of Zeus: Hera, his wife, became so angry, she turn Callisto into a bear, and then picked her up by the tail and hung her in the sky, which is why she has such a long tail (most bears don't). Hera put Callisto just in front of Canes Venatici, the hunting dogs, with chase her around the Pole Star, Polaris, forever. Ursa Minor, the little bear, is the constellation Polaris is in: it is Callisto's child. Two stars at the end of the bowl of the dipper point to Polaris. One can use the dipper to point to other constellations, too: the other two stars in the bowl point down to Regulus, the first magnitude star in Leo the lion. The handle of the Big Dipper points to Arcturus, a first-magnitude star in the constellation Bootes, the herdsman. If one continues following this arc, one comes to another first-magnitude star, Spica, in the constellation Virgo, the maiden. One can remember this by "follow the arc to Arcturus, and speed on to Spica." Virgo was Persephone, goddess of fertility; when she arrived in the sky in Spring the Earth bloomed, and when she left the sky in Fall, it withered. In the Summer sky is the Summer Triangle. The triangle is an asterism composed of three first-magnitude stars, Vega, Deneb, and Altair. Vega is in the constellation Lyra, the Lyre. It is a distinctive little constellation, with five third- to fourth-magnitude stars within 10 degrees, mostly south of Vega. Lyra the Lyre is the instrument of Orpheus, the greatest of musicians. Deneb is in the constellation Cyngus the Swan. Cygnus is Zeus, who appeared to Leda in the form of a swan. Altair is in the constellation Aquila, the Eagle, which depicts another manifestation of Zeus. Delphinus, the dolphin, is a distinctive little constellation, between Cygnus and Aquila. In the myth of Bacchus, the god of wine, Bacchus fell asleep on the beach, and was kidnapped by pirate sailors, who thought someone so well-dressed must be a prince. Bacchus woke up and told them who he was, and the sailors didn't believe him. Bacchus then revealed himself in all his glory, growing to such a large size, he filled the ship, with vines entwining the sails. The sailors panicked and jumped into the sea. Bacchus felt sorry for them, and turned them into dolphins. The ancient Greeks thought this explained why dolphins are so intelligent. (There is a similar story involving Julius Caesar, the Roman emperor---not mythological, but a real, historical person. The Romans were a less romantic but more practical people than the Greeks, much like America is to England, and this story shows the difference. Again, pirates kidnapped Caesar, and took him to sea. Again, Caesar told them who he was, and they laughed at him. The difference is that Caesar didn't turn them into dolphins, or anything like that. He had them crucified.) Hercules is in the spring sky, just west of the Summer Triangle. Hydra, a monster he slew, straddles the equator, and stretches over 100 degrees across the sky. Slaying the hydra was the second of his twelve labors; the first was when he slew the Nemean Lion, a lion with a hide so thick, weapons couldn't pierce it. After strangling it with his enormous strength, he skinned it with his own claws, and wore the skin as armor: this is why depictions of Hercules often show him wearing a lion skin. The constellation Hercules is also next to the constellation Leo, the lion. Hercules is just south of the northern constellation Draco, the dragon. There were many dragons in Greek mythology, but this one is probably Ladon, the dragon Hercules slew while carrying out the eleventh of his twelve labors. Ladon guarded the tree bearing golden apples, at the end of the world; Hercules had to ask Atlas, the Titan who held up the sky, to pick them for him, or else he would die. Hercules, with his great strength, was able to hold up the sky, and Atlas, freed of his burden, almost left him there: only because Hercules tricked him into holding up the sky again, "to make a pad of the lion skin," did Hercules manage to get away. Constellations in the fall sky include Pegasus, Perseus, Andromeda, Cetus, Casseiopeia, and Cepheus. The Great Square of Pegasus is an easily identifiable asterism, again helpful for finding the other constellations. Perseus the Swordsman has just cut off the head of Medusa, a monster so ugly that looking at her would turn someone into stone. Perseus carries the head in his hand, at the location of the eclipsing binary star Algol, the Demon's Eye. This star, easily visible to the unaided eye, noticeably changes brightness, because it is an eclipsing binary. Perseus, a mortal son of Zeus, had help from his immortal siblings. He is flying with the winged hat and sandals borrowed from Hermes, or Mercury, the messenger of the gods. He cut off Medusa's head with a sharp knife borrowed from Artemis, goddess of the hunt. He also had the polished shield of Athena, the goddess of wisdom, and was able to look at Medusa without being turned into stone, because he looked at the reflection in the shield. In the constellation, he is shown saving Andromeda, the princess, from being eaten by Cetus, the whale. She was chained to a rock for this to appease Poseidon, god of the sea, who was angry because her mother, depicted in the constellation Casseiopeia the Queen, had boasted she was more beautiful than his daughters. Her husband, depicted in the constellation Cepheus the King, looks on. Next to Andromeda is the constellation Pegasus, the flying horse, which sprang from the severed head of Medusa, much to the surprise of Perseus. It was later tamed by Bellerophon, who slew the Chimera, a monster with three heads, one of a lion, one of a goat, and one of a snake. The constellation Ares, the ram, is also visible in fall. Ares was a magical, flying ram, with a golden fleece. A band of heroes, including both Orpheus and Hercules, and led by Jason, recovered this fleece, after a long voyage across the Black Sea on Argo, the ship. Argo is also a constellation, but it is no longer used: it has been broken up into four constellations: Vela the sail, Carina the keel, Puppis the stern, and Pyxis, the compass. The ancient Greeks did not have compasses, though: these constellations are all too far south to be seen well from Greece, and most were named in Europe since the 1600s. A southern constellation that is an exception is Sculptor. This sculptor was Pygmalion, who created a statute of a woman so beautiful, he fell in love with it. A prayer to Aphrodite, the love goddess, was answered: the statue turned into a woman. There are many other myths and legends, about many other constellations. Telling them all could fill a book, and indeed, there are several wonderful books in which you can read more about these stories. D'Aulaires' Book of Greek Myths by Ingri and Edgar Parin D'Aulaire is a children's book, but it's still my favorite on mythology, partly because it's so beautifully illustrated. The Metamorphoses, by Ovid, is still in print in several translations into English, and is the definitive source of most of Greek mythology. Finally, The Stars, by H. A. Rey, is another children's book that adults can read and enjoy. It's my favorite for learning constellations, since the author was brave enough to redraw many constellations, to make them look more like what they're supposed to look like. An extensive source of names of major and minor Greek gods and goddesses, and what major and minor planets they are named after, is The Nine Planets: A Multimedia Tour of the Solar System, by Bill Arnett, at: http://seds.lpl.arizona.edu/billa/tnp/