The Pleiades - May 4, 2020
photo by Styrous®
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!
The Pleiades - May 4, 2020
photo byStyrous®
The Pleiades are an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. It is among the star clusters nearest Earth and is the cluster most obvious to the naked eye (when the air is clear) in the night sky.
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.
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.
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.
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.
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.
Animation of proper motion in 400,000 years—cross-eyed viewing
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.
No comments:
Post a Comment
PLEASE NOTE: comments are moderated BEFORE they are posted so DO NOT appear immediately.
Thank you.