It’s an annual autumn ritual: the reappearance of the glorious Seven Sisters. This moonless week, they rise in the east before 7 p.m. and are nicely up after 8 p.m. They’re then out for the rest of the night.
They’re that small, tightly packed cluster of stars. There’s nothing else like it.
Many a night I saw the Pleiades rising through the mellow shade
Glittering like a swarm of fireflies, tangled in a silver braid.
No obstetrician attended the birth of the Pleiades, 60 million years ago. As these fiercely hot suns awakened from the dazzling and dangerous gaseous nursery, the newborn stars materialized like a distant sunrise in the skies of Earth 400 light-years away.
They seem harmless. But that wasn’t always the case. In ancient times the Pleiades had a strange, sinister reputation. Such medieval rituals as Black Sabbath and All Hallows’ Eve (which evolved into our own Halloween) were set to occur when the Pleiades reached their highest point at midnight. Some have speculated that the rituals are a sort of commemoration of some ancient catastrophe that resulted in great loss of life. Some believe that they may be linked to the Atlantis myth, itself perhaps a legend evolved from the awesome eruption of the Santorini [then called Thera] volcano in 1450 BC that devastated the Minoan civilization on nearby Crete.
The Pleiades had an odd importance to civilizations throughout time and around the world. In Egypt they were revered as one of the forms of the goddess Isis. In ancient Persia the date in which they reached their highest midnight ascendancy was marked with ceremony. In Mayan and Aztec culture, this same yearly occasion had a forbidding undertone, and was given tremendous importance, with at least one city’s streets and pyramid aligned with the setting of the Pleiades.
In Japan their ancient name is Subaru. Until very recently, the six companies that merged to produce automobiles in 1953 placed a crude star map of the Pleiades on each of their cars. Over the years, its single bright star has been portrayed as ever-more-luminous and increasingly separated from the others. Some revelation of corporate infighting?
To the Greeks, they’re simply the daughters of Atlas. But why seven sisters? That’s the real mystery. After all, normal eyesight readily sees only six: the same number found on the Subaru insignia.
If you can see a seventh, then you should be able to see an eighth as well. How many you can perceive tells as much about the purity of your sky as the state of your vision. With good eyes in a rural setting, nine are a cinch and even 11 aren’t impossible.
The real thrill comes when the proper instrument is pointed their way. Not a giant telescope; that would be a mistake. Far better is a simple pair of binoculars, because low power and wide field are the ticket. Beginners often gasp when first seeing the Pleiades through binoculars. Suddenly dozens spring into visibility, and their blue-white color becomes obvious as well.
But again, why seven sisters when the average eye sees six? Why have civilizations as disparate as the ancient Greeks, Australian aborigines and Japanese all possessed legends of the “lost Pleiad” that have persisted through the centuries? Even 2,000 years ago, a Greek poet wrote: “…their number seven, though the myths often say…that one has passed away.”
One clue is that, as binoculars reveal, they’re blue: a color that indicates stellar youth. Young, hot giant stars are often unstable, gobbling up their nuclear fuel in an adolescent frenzy that frequently produces instability.
They’re in their infancy even today; our own Sun has been around 250 times longer. The dinosaurs gazed unconcernedly into a sky empty of the Sisters, which sprang into view just before we ourselves did. And, since such massive stars die young, the Pleiades will be long gone when most of the galaxy’s stars are still enjoying middle age. Toddling gracefully across November’s chilly skies, the newborn sisters are only for now.
Want to know more? To read Bob’s previous “Night Sky” columns, visit our Almanac Weekly website at HudsonValleyAlmanacWeekly.com.