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For the last couple of weeks I've noticed a series of lights in the sky over the building across the way from my studio. At first I thought it was an airplane but it didn't move at all. I was completely mystified; I couldn't figure out what it was.
Last night it suddenly dawned on me; it is the Pleiades, also known as The Seven Sisters! It has been decades since I've been able to see them; the air has been so polluted they were not visible. Now that there are few cars and almost no planes flying, the air has been crystal clear and there they were!

Man has known of the
Pleiades since ancient times and
have been known to cultures all around the world, including the Celts, Hawaiians (who call them Makaliʻi), Māori (who call them Matariki), Aboriginal Australians (from several traditions), the Persians (who called them پروین Parvīn or پروی Parvī), the Arabs (who called them Thurayya), the Chinese (who called them 昴 mǎo), the Quechua, the Japanese, the Maya, the Aztec, the Sioux, the Kiowa, and the Cherokee. In Hinduism, the Pleiades are known as Krittika and are associated with the war-god Kartikeya. They are also mentioned three times in the Bible.
The earliest-known depiction of the Pleiades is likely a Northern German bronze age artifact known as the Nebra sky disk, dated to approximately 1600 BC; the cluster of dots in the upper right portion of the disk are believed to be the Pleiades.
Nebra sky disk, circa 1600 BC
Galileo Galilei was the first
astronomer to view the
Pleiades through a
telescope.
He thereby discovered that the cluster contains many stars too dim to
be seen with the naked eye. He published his observations, including a
sketch of the Pleiades showing 36 stars, in his treatise
Sidereus Nuncius in March 1610.
Galileo's drawings of the Pleiades star cluster from Sidereus Nuncius
In
Japan, the constellation is mentioned under the name Mutsuraboshi ("six stars") in the 8th-century
Kojiki. The constellation is now known in Japan as Subaru. It was chosen as the brand name of
Subaru automobiles to reflect the origins of the firm as the joining of five companies, and is depicted in the firm's six-star logo.
Subaru logo
The
Pleiades have long been known to be a physically related group of stars rather than any chance alignment.
John Michell
calculated in 1767 that the probability of a chance alignment of so
many bright stars was only 1 in 500,000, and so surmised that the
Pleiades and many other clusters of stars must be physically related. When studies were first made of the stars'
proper motions,
it was found that they are all moving in the same direction across the
sky, at the same rate, further demonstrating that they were related.
Stars of Pleiades with color and 10,000-year backwards proper motion shown
The nine brightest stars of the
Pleiades are named for the
Seven Sisters of
Greek mythology:
Sterope,
Merope,
Electra,
Maia,
Taygeta,
Celaeno, and
Alcyone, along with their parents
Atlas and
Pleione.
Below is
an animation of proper motion in 400,000 years, however, it involves using cross-eyed viewing; looking at the right image with the left eye and at the left image with the right eye (it takes a bit of practice); it is easier if you click on the image to make it larger.
Astronomers estimate that the age of the
Pleiades is about 115 million years; the cluster will survive for about another 250
million years, after which it will disperse due to gravitational
interactions with its galactic neighborhood.
Viewfinder links:
Here's to a clear future!
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