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[[File:390px-Pleiades large.jpg|thumb|Pleiades or Messier 45]] | |||
In astronomy, the Pleiades or Seven Sisters (Messier 45 or M45), is an open star cluster containing middle-aged hot B-type stars located in the constellation of [[Taurus]]. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky. The celestial entity has several meanings in different cultures and traditions. | In astronomy, the Pleiades or Seven Sisters (Messier 45 or M45), is an open star cluster containing middle-aged hot B-type stars located in the constellation of [[Taurus]]. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky. The celestial entity has several meanings in different cultures and traditions. | ||
The cluster is dominated by hot blue and extremely luminous stars that have formed within the last 100 million years. Dust that forms a faint reflection nebulosity around the brightest stars was thought at first to be left over from the formation of the cluster (hence the alternative name Maia Nebula after the star Maia), but is now known to be an unrelated dust cloud in the interstellar medium, through which the stars are currently passing. Computer simulations have shown that the Pleiades was probably formed from a compact configuration that resembled the Orion Nebula. Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood. | The cluster is dominated by hot blue and extremely luminous stars that have formed within the last 100 million years. Dust that forms a faint reflection nebulosity around the brightest stars was thought at first to be left over from the formation of the cluster (hence the alternative name Maia Nebula after the star Maia), but is now known to be an unrelated dust cloud in the interstellar medium, through which the stars are currently passing. Computer simulations have shown that the Pleiades was probably formed from a compact configuration that resembled the Orion Nebula. Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood. | ||
The name of the Pleiades comes from Ancient Greek. It probably derives from plein ('to sail') because of the cluster's importance in delimiting the sailing season in the Mediterranean Sea: 'the season of navigation began with their heliacal rising'. | The name of the Pleiades comes from Ancient Greek. It probably derives from plein ('to sail') because of the cluster's importance in delimiting the sailing season in the Mediterranean Sea: 'the season of navigation began with their heliacal rising'. However, the name was later mythologised as the name of seven divine sisters, whose name was imagined to derive from that of their mother Pleione, effectively meaning 'daughters of Pleione'. However, in reality the name of the star-cluster almost certainly came first, and Pleione was invented to explain it. | ||
==History== | ==History== | ||
The Pleiades are a prominent sight in winter in the Northern Hemisphere, and have been known since antiquity to cultures all around the world, including the Celts, Māori, Aboriginal Australians, the Persians, the Arabs (known as Thurayya), the Chinese, the Japanese, the Maya, the Aztec, and the Sioux and Cherokee. In Hinduism, the Pleiades are known as Krittika and are associated with the war-god Kartikeya (Murugan, Skanda), who derives his name from them. The god is raised by the six Krittika sisters, also known as the Matrikas. He is said to have developed a face for each of them. | The Pleiades are a prominent sight in winter in the Northern Hemisphere, and have been known since antiquity to cultures all around the world, including the Celts, Māori, Aboriginal Australians, the Persians, the Arabs (known as Thurayya), the Chinese, the Japanese, the Maya, the Aztec, and the Sioux and Cherokee. In Hinduism, the Pleiades are known as Krittika and are associated with the war-god Kartikeya (Murugan, Skanda), who derives his name from them. The god is raised by the six Krittika sisters, also known as the Matrikas. He is said to have developed a face for each of them. | ||
[[File:330px-M45map.jpg|thumb|Map of the Pleiades]] | |||
The Babylonian star catalogues name the Pleiades MUL.MUL or "star of stars", and they head the list of stars along the ecliptic, reflecting the fact that they were close to the point of vernal equinox around the 23rd century BC. The earliest known depiction of the Pleiades is likely a bronze age artifact known as the Nebra sky disk, dated to approximately 1600 BC. Some Greek astronomers considered them to be a distinct constellation, and they are mentioned by Hesiod, and in Homer's Iliad and Odyssey. They are also mentioned three times in the Bible (Job 9:9 and 38:31, as well as Amos 5:8). Some scholars of Islam suggested that the Pleiades (ath-thurayya) are the star mentioned in the sura (chapter) Najm of the Quran. | The Babylonian star catalogues name the Pleiades MUL.MUL or "star of stars", and they head the list of stars along the ecliptic, reflecting the fact that they were close to the point of vernal equinox around the 23rd century BC. The earliest known depiction of the Pleiades is likely a bronze age artifact known as the Nebra sky disk, dated to approximately 1600 BC. Some Greek astronomers considered them to be a distinct constellation, and they are mentioned by Hesiod, and in Homer's Iliad and Odyssey. They are also mentioned three times in the Bible (Job 9:9 and 38:31, as well as Amos 5:8). Some scholars of Islam suggested that the Pleiades (ath-thurayya) are the star mentioned in the sura (chapter) Najm of the Quran. | ||