Pleiades: The Seven Sisters

The Pleiades, often referred to as the Seven Sisters, is a group of stars that is richly steeped in lore. Cultures all over the world have legends about this little cluster of stars, likely because they are bright and tightly packed together and naturally draw the eye. Read on to learn how to find the Pleiades, and some of the stories associated with these stars.

Finding the Pleiades starts with finding Orion. Can you see him? Click image to enlarge. Image Credit: Stellarium and Me

The Pleiades are a tightly packed group of bright stars. Some people see five, some six, and if you use a telescope, you can see many, many more. The stars actually are arranged in a bit of a dipper shape, so the Pleiades are sometimes confused with the Little Dipper. To find them, first find Orion. Can you see him in the image above (set for Peoria at about 8:30 at night)? Look for the three bright stars in line that make his belt. Once you find Orion's belt, follow the upward slant of his belt in a line until you come to that little cluster of stars - the Pleiades! If you need help, check out the image below. 

Use the slant of Orion's belt to find the Pleiades. Image Credit: Stellarium and Me

There are about 1,000 stars in the Pleiades cluster. A star cluster is a group of stars that were formed out of the same molecular cloud, or nebula (think of the Orion nebula forming new stars). The stars are relatively close to one another, and loosely bound together by mutual gravitational attraction. Because they were formed out of the same cloud, they are roughly the same age. The Pleiades stars are about 100 million years old, and about 444 light-years away from the Sun. 

A long exposure of the Pleiades by a talented amateur astronomer, Bob Star. Image Credit

If you find the Pleiades on a clear night, sometimes you can see that the stars have a fuzziness around them. The fuzziness is caused by a reflection nebula nearby, a cloud of gas and dust that is drifting through the Pleiades. It is beautiful:

The nine brightest stars of the Pleiades are named for the Seven Sisters of Greek mythology and their parents. The parents are the Titan, Atlas, (who carried the sky on his back) and Pleione, an ocean nymph. Atlas had many children - the Hyades, Hyas, Calypso, and the Pleiades: Sterope, Merope, Electra, Maia, Taygeta, Celaeno, and Alcyone.

The brightest stars in the cluster are named for the Seven Sisters in Greek mythology. Image Credit

There are many stories that involve the Seven Sisters in Greek mythology. They were nymphs and companions to the goddess Artemis, goddess of the hunt and the Moon. They all have stories of trysts with gods, and Maia was said to be the mother of Hermes, son of Zeus. According to several stories, the Seven Sisters became stars after they all committed suicide because they were so saddened either by the fate of their father Atlas (condemned to hold the sky up for eternity) or their sisters the Hyades, who cried themselves to death after their brother Hyas died while hunting - not a very happy family. 

Another Greek story says that after Atlas left them to hold up the sky, Orion began pursuing all of the Seven Sisters, so Zeus transformed them into doves, and then into stars, so that Atlas wouldn't worry about their safety. 

The Pleiades, by Elidu Vedder. Check out his work, it is fantastic. Image Credit

While the Pleiades are often called the Seven Sisters, there are really only six visible stars in the group, which has led to stories and art imagining what happened to the seventh sister. 

Lost Pleiad, by William-Adolphe Bouguereau. Image Credit

All the mythology of the Pleiades and how they got in the sky may have been created after the star cluster was already named. The name Pleiades likely derives from the ancient Greek word plein, which meant "to sail". The Greeks were avid star watchers and paid close attention to the heliacal rising of stars, or when a star became visible in the East just before sunrise for the first time in a season, after a long period of being obscured by sunlight. The Greeks would watch for the heliacal rising the Pleiades to know when it was safe to sail the seas again, in early summer. The poet Hesiod warned: 

"And if longing seizes you for sailing the stormy seas,

when the Pleiades flee mighty Orion

and plunge into the misty deep

and all the gusty winds are raging,

then do not keep your ship on the wine-dark sea

but, as I bid you, remember to work the land."

(Works and Days 618-23)

In other words, don't sail in the fall and winter, when the Pleiades set just before dawn, rather, work the land. 

There are many cultural myths surrounding the Pleiades star cluster. The Celts, Maori, Aboriginal Australians, the Persians, the Arabs, Chinese, Japanese, Maya, Aztec, Sioux, and Cherokee all had stories about this bright little cluster of stars. Check out this entry in Star Tales to read more of the stories.

So look up on a clear night over the coming weeks. You should be able to find the Pleiades, even in a light polluted city.  Visit the Dome Planetarium at the Peoria Riverfront Museum to learn more about constellations and the latest news from space. Follow us on Facebook and Twitter for daily updates! 

Are you going to run our 5K?