These clear, crisp winter nights are ideal for star-gazing. Find a dark spot away from city lights, and look up to find your favorite constellation—the Big Dipper (aka the Drinking Gourd), Orion the Hunter with his star-studded belt, his prey Taurus the Bull, or the closely woven, sparkling star cluster known as the Pleiades or Seven Sisters. Alfred, Lord Tennyson described it best in his 1838 poem “Locksley Hall”:
Many a night I saw the Pleiads, rising thro’ the mellow shade,
Glitter like a swarm of fireflies tangled in a silver braid.
This constellation—one of the most beautiful in the sky—has been an object of fascination since ancient times, leading to its wide-ranging association with a variety of cultural spheres beyond astronomy, from mythology, to poetry, to colleges—even to cars!
The Pleiades, also known as Messier 45, comprise an open star cluster located in the constellation Taurus. The cluster is dominated by extremely luminous hot blue stars that formed within the last 100 million years. Because it is among the nearest star clusters to Earth, it is the one most obvious to the naked eye in the night sky. Although it actually contains hundreds of stars, only a handful—typically six or seven, but up to 14 depending on local observing conditions—are commonly visible. In the northern hemisphere, the constellation appears above and to the right of Orion as one faces south, and it reaches its highest point in the sky at around 4 a.m. in September, midnight in November (when it shines from dusk until dawn), and 8 p.m. in January. These days, I see the Pleiades almost straight overhead, closely grouped in a somewhat triangular shape.
The name Pleiades (pron. plee-uh-deez) comes from ancient Greek probably deriving from plein («to sail») because the cluster first becomes visible on the eastern horizon at the start of navigation season in the Mediterranean Sea (late May). In Greek mythology, the name was given to the seven daughters of the Titan Atlas and the sea-nymph Pleione. One story of how these sisters became stars relates that after Atlas was forced to carry the heavens on his shoulders, all seven sisters committed suicide because they were so saddened by his fate as well as by the loss of their five half-sisters, the Hyades—weeping nymphs believed to bring rain, who comprise the nearest star cluster and form the V of Taurus’ face. Zeus, the ruler of the Greek gods, immortalized the sisters by transforming them into stars and placing them together in the sky. Aldebaran, the brightest star in Taurus’ V-shaped face, is Arabic for follower in reference to this star forever chasing the Pleiades across the heavens. The Pleiades are mentioned in Homer’s Iliad and Odyssey as well as in the Bible. The nine brightest stars of the Pleiades constellation are named for these seven sisters: Sterope, Merope, Electra, Maia, Taygeta, Celaeno, and Alcyone, along with their parents Atlas and Pleione.
I first became fascinated with this constellation in AP French class, when we studied the group of young French Renaissance poets who called themselves La Pléiade (pron. play-ee-ahd in French) after the the original Pleiad of seven Alexandrian poets and tragedians who adopted this name during the 3rd century BC. They, in turn, named themselves after the seven-star constellation that glittered in the heavens on a clear winter’s night both then and now! The 16th century French Pléiade included Pierre de Ronsard, Joachim du Bellay, Jean-Antoine de Baïf, and others whose aim was to produce a new and revitalized French poetry that could stand up to comparison with the verse of classical antiquity by such greats as Horace, Virgil, and Ovid. Ronsard wrote exquisite nature poems, including, appropriately, the “Hymne du Ciel,” or “Hymn of the Sky.”
Have you ever wondered how Subaru chose the starry logo that adorns its cars? I only recently discovered that the word “subaru”—which literally means “unite” or “gather together” in Japanese—is also the Japanese name for the Pleiades star cluster, which is represented in the brand’s logo! This word was chosen as the brand name of Subaru automobiles to reflect the origins of the firm as the joining of five companies. Since one of the seven stars in the cluster is usually invisible, there are only six stars in the Subaru logo.
The name “Seven Sisters” is also used to refer to seven outstanding women’s liberal arts colleges in the Northeast—namely Smith, Radcliffe, Wellesley, Bryn Mawr, Vassar, Barnard, and Mount Holyoke. This name was officially adopted during the 1926 Seven College Conference, which was aimed at organizing common fundraising for the colleges (Vassar has since become coed, while Radcliffe effectively merged with its male counterpart, Harvard). The name has even transferred in common usage to a group of mountains in western Massachusetts not far from these colleges.
Of course, astronomers appreciate this unique constellation as much as the rest of us; NASA chose this name for its most powerful supercomputer, perhaps because, like the star cluster, it consists of a computer cluster. “Pleiades … represents NASA’s state-of-the-art technology… enabling NASA scientists and engineers to conduct modeling and simulation for NASA missions. This distributed-memory SGI ICE cluster is connected with InfiniBand in a dual-lane hypercube technology.” So we’ve come full circle, because that description is Greek to me!