Great year
Encyclopedia
The Great Year is an archaic cosmological conception, found in different cultures, which acquired new interpretations with the development of astronomical knowledge In the Western tradition Plato
has been the main source for the idea, so it was also frequently called 'Platonic year' (Latin: annus platonicus). Nearly two centuries after his time Hipparchus
established the period of equinox precession, a finding which took the same name and provided a value for it. Currently one precession cycle is estimated to be about 25,765 years. The Babylonian, Indian or astrological sources offer different views about the great year and its length. More recently coined is the "cosmic" or "galactic year
", the period in which the solar system
moves around the center of our galaxy
.
, who in his Timaeus
defined the "perfect year" as the return of the celestial bodies (planets) and the fixed stars (circle of the Same) to their original positions:
The Platonic year, based on the revolution of the planets and estimated by Macrobius as lasting 15,000 solar years, has no connection to the "precessional period of 36,000 years", caused by the slow gyration of the Earth's axis and discovered by the Greek astronomor Hipparchus
:
The confusion originates with the astronomer Ptolemy
, who "adopted the larger, erroneous, figure, with the result that henceforth the two versions of the Great Year - the Platonic Great Year, defined by the planets, and the precessional, defined by the stars - were to be increasingly confused."
"Some people called it the Yuga cycle, others called it the Grand cycle and others the Perfect Year...But the most common name found in use from ancient Europe to ancient China, was simply the Great Year".
the idea is traced back to Theon of Alexandria
(4th.c) who credits it to older astrologers. In the middle ages it was favored by Arabian astronomers and Copernic
also endorsed it. As the name 'trepidation' suggests it was not considered to be a 'year' which is most commonly thought as circular.
The duration of the precession cycle, the time it takes for the equinox to precess 360 degrees relative to the fixed stars, is often given as 25,920 or 26,000 years. In reality the exact duration cannot be given, as the rate of precession is changing over time. This speed is currently 243.8 microradians (50.3 arcseconds) per year which would give 25,765 years for one cycle to complete.
The precessional speed is slightly increasing each year, and therefore the cycle period is decreasing. Numerical simulations of the solar system over a period of millions of years give a period of 257 centuries. but no one is certain of the exact precession rate over long periods of time. Near the turn of the 20th century astronomer Simon Newcomb
invented a "constant" to account for the increasing annual precession rate. Over the last 100 years this constant has been found to have underestimated the actual acceleration in the rate.
, Treta, Dvapara, and Kali
yugas, and also add to one half a precessional cycle, as calculated by the Indian sage Sri Yukteswar Giri
. In his book, The Holy Science
, first published in 1894 as Kaivalya Darsanam, Yukteswar describes the Great Year as a period of time wherein the earth goes through a "complete change, both externally in the material world, and internally in the intellectual or electric world" with four rising ages and four descending ages, equal in length to one complete precession of the equinox. Other Indian scholars put the length at millions of years, a period of time unrelated to the precession cycle.
According to Giorgio de Santillana
, the late Professor of the History and Philosophy of Science at M.I.T and Hertha von Dechend, in their book Hamlet's Mill
, published in 1969 by Gambit, there are over 200 myths or folk stories from over thirty ancient cultures that refer to a Great Year tied to the movement of the equinox or the motion of the heavens.
has been the main source for the idea, so it was also frequently called 'Platonic year' (Latin: annus platonicus). Nearly two centuries after his time Hipparchus
established the period of equinox precession, a finding which took the same name and provided a value for it. Currently one precession cycle is estimated to be about 25,765 years. The Babylonian, Indian or astrological sources offer different views about the great year and its length. More recently coined is the "cosmic" or "galactic year
", the period in which the solar system
moves around the center of our galaxy
.
, who in his Timaeus
defined the "perfect year" as the return of the celestial bodies (planets) and the fixed stars (circle of the Same) to their original positions:
The Platonic year, based on the revolution of the planets and estimated by Macrobius as lasting 15,000 solar years, has no connection to the "precessional period of 36,000 years", caused by the slow gyration of the Earth's axis and discovered by the Greek astronomor Hipparchus
:
The confusion originates with the astronomer Ptolemy
, who "adopted the larger, erroneous, figure, with the result that henceforth the two versions of the Great Year - the Platonic Great Year, defined by the planets, and the precessional, defined by the stars - were to be increasingly confused."
"Some people called it the Yuga cycle, others called it the Grand cycle and others the Perfect Year...But the most common name found in use from ancient Europe to ancient China, was simply the Great Year".
the idea is traced back to Theon of Alexandria
(4th.c) who credits it to older astrologers. In the middle ages it was favored by Arabian astronomers and Copernic
also endorsed it. As the name 'trepidation' suggests it was not considered to be a 'year' which is most commonly thought as circular.
The duration of the precession cycle, the time it takes for the equinox to precess 360 degrees relative to the fixed stars, is often given as 25,920 or 26,000 years. In reality the exact duration cannot be given, as the rate of precession is changing over time. This speed is currently 243.8 microradians (50.3 arcseconds) per year which would give 25,765 years for one cycle to complete.
The precessional speed is slightly increasing each year, and therefore the cycle period is decreasing. Numerical simulations of the solar system over a period of millions of years give a period of 257 centuries. but no one is certain of the exact precession rate over long periods of time. Near the turn of the 20th century astronomer Simon Newcomb
invented a "constant" to account for the increasing annual precession rate. Over the last 100 years this constant has been found to have underestimated the actual acceleration in the rate.
, Treta, Dvapara, and Kali
yugas, and also add to one half a precessional cycle, as calculated by the Indian sage Sri Yukteswar Giri
. In his book, The Holy Science
, first published in 1894 as Kaivalya Darsanam, Yukteswar describes the Great Year as a period of time wherein the earth goes through a "complete change, both externally in the material world, and internally in the intellectual or electric world" with four rising ages and four descending ages, equal in length to one complete precession of the equinox. Other Indian scholars put the length at millions of years, a period of time unrelated to the precession cycle.
According to Giorgio de Santillana
, the late Professor of the History and Philosophy of Science at M.I.T and Hertha von Dechend, in their book Hamlet's Mill
, published in 1969 by Gambit, there are over 200 myths or folk stories from over thirty ancient cultures that refer to a Great Year tied to the movement of the equinox or the motion of the heavens.
has been the main source for the idea, so it was also frequently called 'Platonic year' (Latin: annus platonicus). Nearly two centuries after his time Hipparchus
established the period of equinox precession, a finding which took the same name and provided a value for it. Currently one precession cycle is estimated to be about 25,765 years. The Babylonian, Indian or astrological sources offer different views about the great year and its length. More recently coined is the "cosmic" or "galactic year
", the period in which the solar system
moves around the center of our galaxy
.
, who in his Timaeus
defined the "perfect year" as the return of the celestial bodies (planets) and the fixed stars (circle of the Same) to their original positions:
The Platonic year, based on the revolution of the planets and estimated by Macrobius as lasting 15,000 solar years, has no connection to the "precessional period of 36,000 years", caused by the slow gyration of the Earth's axis and discovered by the Greek astronomor Hipparchus
:
The confusion originates with the astronomer Ptolemy
, who "adopted the larger, erroneous, figure, with the result that henceforth the two versions of the Great Year - the Platonic Great Year, defined by the planets, and the precessional, defined by the stars - were to be increasingly confused."
"Some people called it the Yuga cycle, others called it the Grand cycle and others the Perfect Year...But the most common name found in use from ancient Europe to ancient China, was simply the Great Year".
the idea is traced back to Theon of Alexandria
(4th.c) who credits it to older astrologers. In the middle ages it was favored by Arabian astronomers and Copernic
also endorsed it. As the name 'trepidation' suggests it was not considered to be a 'year' which is most commonly thought as circular.
The duration of the precession cycle, the time it takes for the equinox to precess 360 degrees relative to the fixed stars, is often given as 25,920 or 26,000 years. In reality the exact duration cannot be given, as the rate of precession is changing over time. This speed is currently 243.8 microradians (50.3 arcseconds) per year which would give 25,765 years for one cycle to complete.
The precessional speed is slightly increasing each year, and therefore the cycle period is decreasing. Numerical simulations of the solar system over a period of millions of years give a period of 257 centuries. but no one is certain of the exact precession rate over long periods of time. Near the turn of the 20th century astronomer Simon Newcomb
invented a "constant" to account for the increasing annual precession rate. Over the last 100 years this constant has been found to have underestimated the actual acceleration in the rate.
, Treta, Dvapara, and Kali
yugas, and also add to one half a precessional cycle, as calculated by the Indian sage Sri Yukteswar Giri
. In his book, The Holy Science
, first published in 1894 as Kaivalya Darsanam, Yukteswar describes the Great Year as a period of time wherein the earth goes through a "complete change, both externally in the material world, and internally in the intellectual or electric world" with four rising ages and four descending ages, equal in length to one complete precession of the equinox. Other Indian scholars put the length at millions of years, a period of time unrelated to the precession cycle.
According to Giorgio de Santillana
, the late Professor of the History and Philosophy of Science at M.I.T and Hertha von Dechend, in their book Hamlet's Mill
, published in 1969 by Gambit, there are over 200 myths or folk stories from over thirty ancient cultures that refer to a Great Year tied to the movement of the equinox or the motion of the heavens.
Plato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
has been the main source for the idea, so it was also frequently called 'Platonic year' (Latin: annus platonicus). Nearly two centuries after his time Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...
established the period of equinox precession, a finding which took the same name and provided a value for it. Currently one precession cycle is estimated to be about 25,765 years. The Babylonian, Indian or astrological sources offer different views about the great year and its length. More recently coined is the "cosmic" or "galactic year
Galactic year
The galactic year, also known as a cosmic year, is the duration of time required for the Solar System to orbit once around the center of the Milky Way Galaxy. Estimates of the length of one orbit range from 225 to 250 million "terrestrial" years....
", the period in which the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
moves around the center of our galaxy
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
.
Confusion of precession and Platonic year
The Great Year, based on the cycle of precession, is often called Platonic year based on a confusion with a concept defined by the philosopher PlatoPlato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
, who in his Timaeus
Timaeus
Timaeus is a Greek name, meaning "Honour". It may refer to:*Timaeus , a Socratic dialogue by Plato*Timaeus of Locri, the 5th-century Pythagorean philosopher, appearing in Plato's dialogue...
defined the "perfect year" as the return of the celestial bodies (planets) and the fixed stars (circle of the Same) to their original positions:
The Platonic year, based on the revolution of the planets and estimated by Macrobius as lasting 15,000 solar years, has no connection to the "precessional period of 36,000 years", caused by the slow gyration of the Earth's axis and discovered by the Greek astronomor Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...
:
The confusion originates with the astronomer Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
, who "adopted the larger, erroneous, figure, with the result that henceforth the two versions of the Great Year - the Platonic Great Year, defined by the planets, and the precessional, defined by the stars - were to be increasingly confused."
"Some people called it the Yuga cycle, others called it the Grand cycle and others the Perfect Year...But the most common name found in use from ancient Europe to ancient China, was simply the Great Year".
Astronomical value of the precession cycle
The empirical data for the precession of the equinox do not warrant the extrapolation to a full cycle and from the antiquity to Modern times many scholars doubted its existence. Astronomical phenomena often exhibit a movement within a limited range and it was surmised the displacement of the vernal point is of this type. Known as the theory of trepidationTrepidation
According to a medieval theory of astronomy, trepidation is oscillation in the precession of the equinoxes. The theory was popular from the 9th to the 16th centuries....
the idea is traced back to Theon of Alexandria
Theon of Alexandria
Theon was a Greek scholar and mathematician who lived in Alexandria, Egypt. He edited and arranged Euclid's Elements and Ptolemy's Handy Tables, as well as writing various commentaries...
(4th.c) who credits it to older astrologers. In the middle ages it was favored by Arabian astronomers and Copernic
Copernic
Copernic Inc. is a company based in Quebec, Canada specializing in web search technology. They also provide home and business software products for desktop, web and mobile users through their web sites.-History:...
also endorsed it. As the name 'trepidation' suggests it was not considered to be a 'year' which is most commonly thought as circular.
The duration of the precession cycle, the time it takes for the equinox to precess 360 degrees relative to the fixed stars, is often given as 25,920 or 26,000 years. In reality the exact duration cannot be given, as the rate of precession is changing over time. This speed is currently 243.8 microradians (50.3 arcseconds) per year which would give 25,765 years for one cycle to complete.
The precessional speed is slightly increasing each year, and therefore the cycle period is decreasing. Numerical simulations of the solar system over a period of millions of years give a period of 257 centuries. but no one is certain of the exact precession rate over long periods of time. Near the turn of the 20th century astronomer Simon Newcomb
Simon Newcomb
Simon Newcomb was a Canadian-American astronomer and mathematician. Though he had little conventional schooling, he made important contributions to timekeeping as well as writing on economics and statistics and authoring a science fiction novel.-Early life:Simon Newcomb was born in the town of...
invented a "constant" to account for the increasing annual precession rate. Over the last 100 years this constant has been found to have underestimated the actual acceleration in the rate.
Early cultures and mythology
The Greeks broke the Great Year into four ages known as the Golden, Silver, Bronze, and Iron Ages,which add to one half of a precessional cycle. The Indian Great Year cycle Yugas is also broken into four periods; the SatyaSatya
Satya is a Sanskrit word that loosely translates into English as "truth" or "correct". It is a term of power due to its purity and meaning and has become the emblem of many peaceful social movements, particularly those centered on social justice, environmentalism and vegetarianism.Sathya is also...
, Treta, Dvapara, and Kali
Kali
' , also known as ' , is the Hindu goddess associated with power, shakti. The name Kali comes from kāla, which means black, time, death, lord of death, Shiva. Kali means "the black one". Since Shiva is called Kāla - the eternal time, Kālī, his consort, also means "Time" or "Death" . Hence, Kāli is...
yugas, and also add to one half a precessional cycle, as calculated by the Indian sage Sri Yukteswar Giri
Sri Yukteswar Giri
Sri Yukteshwar Giri is the monastic name of Priyanath Karar , the guru of Swami Satyananda Giri and Paramahansa Yogananda. Sri Yukteshwar was an educator, astronomer, a Jyotisha , a yogi, and a believer in the Bhagavad Gita and the Bible...
. In his book, The Holy Science
The Holy Science
The Holy Science is a book written by Swami Sri Yukteswar Giri in 1894 under the title Kaivalya Darsanam. Sri Yukteswar states that he wrote The Holy Science at the request of Mahavatar Babaji...
, first published in 1894 as Kaivalya Darsanam, Yukteswar describes the Great Year as a period of time wherein the earth goes through a "complete change, both externally in the material world, and internally in the intellectual or electric world" with four rising ages and four descending ages, equal in length to one complete precession of the equinox. Other Indian scholars put the length at millions of years, a period of time unrelated to the precession cycle.
According to Giorgio de Santillana
Giorgio de Santillana
Giorgio Diaz de Santillana was an Italian-American philosopher of science and historian of science, and professor at MIT....
, the late Professor of the History and Philosophy of Science at M.I.T and Hertha von Dechend, in their book Hamlet's Mill
Hamlet's Mill
Hamlet's Mill by Giorgio de Santillana and Hertha von Dechend Hamlet's Mill (first published by Gambit, Boston, 1969) by Giorgio de Santillana (a professor of the history of science at MIT) and Hertha von Dechend Hamlet's Mill (first published by Gambit, Boston, 1969) by Giorgio de Santillana (a...
, published in 1969 by Gambit, there are over 200 myths or folk stories from over thirty ancient cultures that refer to a Great Year tied to the movement of the equinox or the motion of the heavens.
Significance in astrology
Most astrologers use a precession rate rounded to 50 arc seconds per year to derive a Great Year period of 25,920 years, the period required for the equinox to move through all twelve of the classic zodiacal signs. Some, such as Boris Cristoff prefer to round the age of one sign of the zodiac to 2100 years, which equates to a Great Year duration of 25,200 years.Footnotes
The Great Year is an archaic cosmological conception, found in different cultures, which acquired new interpretations with the development of astronomical knowledge In the Western tradition PlatoPlato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
has been the main source for the idea, so it was also frequently called 'Platonic year' (Latin: annus platonicus). Nearly two centuries after his time Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...
established the period of equinox precession, a finding which took the same name and provided a value for it. Currently one precession cycle is estimated to be about 25,765 years. The Babylonian, Indian or astrological sources offer different views about the great year and its length. More recently coined is the "cosmic" or "galactic year
Galactic year
The galactic year, also known as a cosmic year, is the duration of time required for the Solar System to orbit once around the center of the Milky Way Galaxy. Estimates of the length of one orbit range from 225 to 250 million "terrestrial" years....
", the period in which the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
moves around the center of our galaxy
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
.
Confusion of precession and Platonic year
The Great Year, based on the cycle of precession, is often called Platonic year based on a confusion with a concept defined by the philosopher PlatoPlato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
, who in his Timaeus
Timaeus
Timaeus is a Greek name, meaning "Honour". It may refer to:*Timaeus , a Socratic dialogue by Plato*Timaeus of Locri, the 5th-century Pythagorean philosopher, appearing in Plato's dialogue...
defined the "perfect year" as the return of the celestial bodies (planets) and the fixed stars (circle of the Same) to their original positions:
The Platonic year, based on the revolution of the planets and estimated by Macrobius as lasting 15,000 solar years, has no connection to the "precessional period of 36,000 years", caused by the slow gyration of the Earth's axis and discovered by the Greek astronomor Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...
:
The confusion originates with the astronomer Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
, who "adopted the larger, erroneous, figure, with the result that henceforth the two versions of the Great Year - the Platonic Great Year, defined by the planets, and the precessional, defined by the stars - were to be increasingly confused."
"Some people called it the Yuga cycle, others called it the Grand cycle and others the Perfect Year...But the most common name found in use from ancient Europe to ancient China, was simply the Great Year".
Astronomical value of the precession cycle
The empirical data for the precession of the equinox do not warrant the extrapolation to a full cycle and from the antiquity to Modern times many scholars doubted its existence. Astronomical phenomena often exhibit a movement within a limited range and it was surmised the displacement of the vernal point is of this type. Known as the theory of trepidationTrepidation
According to a medieval theory of astronomy, trepidation is oscillation in the precession of the equinoxes. The theory was popular from the 9th to the 16th centuries....
the idea is traced back to Theon of Alexandria
Theon of Alexandria
Theon was a Greek scholar and mathematician who lived in Alexandria, Egypt. He edited and arranged Euclid's Elements and Ptolemy's Handy Tables, as well as writing various commentaries...
(4th.c) who credits it to older astrologers. In the middle ages it was favored by Arabian astronomers and Copernic
Copernic
Copernic Inc. is a company based in Quebec, Canada specializing in web search technology. They also provide home and business software products for desktop, web and mobile users through their web sites.-History:...
also endorsed it. As the name 'trepidation' suggests it was not considered to be a 'year' which is most commonly thought as circular.
The duration of the precession cycle, the time it takes for the equinox to precess 360 degrees relative to the fixed stars, is often given as 25,920 or 26,000 years. In reality the exact duration cannot be given, as the rate of precession is changing over time. This speed is currently 243.8 microradians (50.3 arcseconds) per year which would give 25,765 years for one cycle to complete.
The precessional speed is slightly increasing each year, and therefore the cycle period is decreasing. Numerical simulations of the solar system over a period of millions of years give a period of 257 centuries. but no one is certain of the exact precession rate over long periods of time. Near the turn of the 20th century astronomer Simon Newcomb
Simon Newcomb
Simon Newcomb was a Canadian-American astronomer and mathematician. Though he had little conventional schooling, he made important contributions to timekeeping as well as writing on economics and statistics and authoring a science fiction novel.-Early life:Simon Newcomb was born in the town of...
invented a "constant" to account for the increasing annual precession rate. Over the last 100 years this constant has been found to have underestimated the actual acceleration in the rate.
Early cultures and mythology
The Greeks broke the Great Year into four ages known as the Golden, Silver, Bronze, and Iron Ages,which add to one half of a precessional cycle. The Indian Great Year cycle Yugas is also broken into four periods; the SatyaSatya
Satya is a Sanskrit word that loosely translates into English as "truth" or "correct". It is a term of power due to its purity and meaning and has become the emblem of many peaceful social movements, particularly those centered on social justice, environmentalism and vegetarianism.Sathya is also...
, Treta, Dvapara, and Kali
Kali
' , also known as ' , is the Hindu goddess associated with power, shakti. The name Kali comes from kāla, which means black, time, death, lord of death, Shiva. Kali means "the black one". Since Shiva is called Kāla - the eternal time, Kālī, his consort, also means "Time" or "Death" . Hence, Kāli is...
yugas, and also add to one half a precessional cycle, as calculated by the Indian sage Sri Yukteswar Giri
Sri Yukteswar Giri
Sri Yukteshwar Giri is the monastic name of Priyanath Karar , the guru of Swami Satyananda Giri and Paramahansa Yogananda. Sri Yukteshwar was an educator, astronomer, a Jyotisha , a yogi, and a believer in the Bhagavad Gita and the Bible...
. In his book, The Holy Science
The Holy Science
The Holy Science is a book written by Swami Sri Yukteswar Giri in 1894 under the title Kaivalya Darsanam. Sri Yukteswar states that he wrote The Holy Science at the request of Mahavatar Babaji...
, first published in 1894 as Kaivalya Darsanam, Yukteswar describes the Great Year as a period of time wherein the earth goes through a "complete change, both externally in the material world, and internally in the intellectual or electric world" with four rising ages and four descending ages, equal in length to one complete precession of the equinox. Other Indian scholars put the length at millions of years, a period of time unrelated to the precession cycle.
According to Giorgio de Santillana
Giorgio de Santillana
Giorgio Diaz de Santillana was an Italian-American philosopher of science and historian of science, and professor at MIT....
, the late Professor of the History and Philosophy of Science at M.I.T and Hertha von Dechend, in their book Hamlet's Mill
Hamlet's Mill
Hamlet's Mill by Giorgio de Santillana and Hertha von Dechend Hamlet's Mill (first published by Gambit, Boston, 1969) by Giorgio de Santillana (a professor of the history of science at MIT) and Hertha von Dechend Hamlet's Mill (first published by Gambit, Boston, 1969) by Giorgio de Santillana (a...
, published in 1969 by Gambit, there are over 200 myths or folk stories from over thirty ancient cultures that refer to a Great Year tied to the movement of the equinox or the motion of the heavens.
Significance in astrology
Most astrologers use a precession rate rounded to 50 arc seconds per year to derive a Great Year period of 25,920 years, the period required for the equinox to move through all twelve of the classic zodiacal signs. Some, such as Boris Cristoff prefer to round the age of one sign of the zodiac to 2100 years, which equates to a Great Year duration of 25,200 years.Footnotes
The Great Year is an archaic cosmological conception, found in different cultures, which acquired new interpretations with the development of astronomical knowledge In the Western tradition PlatoPlato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
has been the main source for the idea, so it was also frequently called 'Platonic year' (Latin: annus platonicus). Nearly two centuries after his time Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...
established the period of equinox precession, a finding which took the same name and provided a value for it. Currently one precession cycle is estimated to be about 25,765 years. The Babylonian, Indian or astrological sources offer different views about the great year and its length. More recently coined is the "cosmic" or "galactic year
Galactic year
The galactic year, also known as a cosmic year, is the duration of time required for the Solar System to orbit once around the center of the Milky Way Galaxy. Estimates of the length of one orbit range from 225 to 250 million "terrestrial" years....
", the period in which the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
moves around the center of our galaxy
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
.
Confusion of precession and Platonic year
The Great Year, based on the cycle of precession, is often called Platonic year based on a confusion with a concept defined by the philosopher PlatoPlato
Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...
, who in his Timaeus
Timaeus
Timaeus is a Greek name, meaning "Honour". It may refer to:*Timaeus , a Socratic dialogue by Plato*Timaeus of Locri, the 5th-century Pythagorean philosopher, appearing in Plato's dialogue...
defined the "perfect year" as the return of the celestial bodies (planets) and the fixed stars (circle of the Same) to their original positions:
The Platonic year, based on the revolution of the planets and estimated by Macrobius as lasting 15,000 solar years, has no connection to the "precessional period of 36,000 years", caused by the slow gyration of the Earth's axis and discovered by the Greek astronomor Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...
:
The confusion originates with the astronomer Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
, who "adopted the larger, erroneous, figure, with the result that henceforth the two versions of the Great Year - the Platonic Great Year, defined by the planets, and the precessional, defined by the stars - were to be increasingly confused."
"Some people called it the Yuga cycle, others called it the Grand cycle and others the Perfect Year...But the most common name found in use from ancient Europe to ancient China, was simply the Great Year".
Astronomical value of the precession cycle
The empirical data for the precession of the equinox do not warrant the extrapolation to a full cycle and from the antiquity to Modern times many scholars doubted its existence. Astronomical phenomena often exhibit a movement within a limited range and it was surmised the displacement of the vernal point is of this type. Known as the theory of trepidationTrepidation
According to a medieval theory of astronomy, trepidation is oscillation in the precession of the equinoxes. The theory was popular from the 9th to the 16th centuries....
the idea is traced back to Theon of Alexandria
Theon of Alexandria
Theon was a Greek scholar and mathematician who lived in Alexandria, Egypt. He edited and arranged Euclid's Elements and Ptolemy's Handy Tables, as well as writing various commentaries...
(4th.c) who credits it to older astrologers. In the middle ages it was favored by Arabian astronomers and Copernic
Copernic
Copernic Inc. is a company based in Quebec, Canada specializing in web search technology. They also provide home and business software products for desktop, web and mobile users through their web sites.-History:...
also endorsed it. As the name 'trepidation' suggests it was not considered to be a 'year' which is most commonly thought as circular.
The duration of the precession cycle, the time it takes for the equinox to precess 360 degrees relative to the fixed stars, is often given as 25,920 or 26,000 years. In reality the exact duration cannot be given, as the rate of precession is changing over time. This speed is currently 243.8 microradians (50.3 arcseconds) per year which would give 25,765 years for one cycle to complete.
The precessional speed is slightly increasing each year, and therefore the cycle period is decreasing. Numerical simulations of the solar system over a period of millions of years give a period of 257 centuries. but no one is certain of the exact precession rate over long periods of time. Near the turn of the 20th century astronomer Simon Newcomb
Simon Newcomb
Simon Newcomb was a Canadian-American astronomer and mathematician. Though he had little conventional schooling, he made important contributions to timekeeping as well as writing on economics and statistics and authoring a science fiction novel.-Early life:Simon Newcomb was born in the town of...
invented a "constant" to account for the increasing annual precession rate. Over the last 100 years this constant has been found to have underestimated the actual acceleration in the rate.
Early cultures and mythology
The Greeks broke the Great Year into four ages known as the Golden, Silver, Bronze, and Iron Ages,which add to one half of a precessional cycle. The Indian Great Year cycle Yugas is also broken into four periods; the SatyaSatya
Satya is a Sanskrit word that loosely translates into English as "truth" or "correct". It is a term of power due to its purity and meaning and has become the emblem of many peaceful social movements, particularly those centered on social justice, environmentalism and vegetarianism.Sathya is also...
, Treta, Dvapara, and Kali
Kali
' , also known as ' , is the Hindu goddess associated with power, shakti. The name Kali comes from kāla, which means black, time, death, lord of death, Shiva. Kali means "the black one". Since Shiva is called Kāla - the eternal time, Kālī, his consort, also means "Time" or "Death" . Hence, Kāli is...
yugas, and also add to one half a precessional cycle, as calculated by the Indian sage Sri Yukteswar Giri
Sri Yukteswar Giri
Sri Yukteshwar Giri is the monastic name of Priyanath Karar , the guru of Swami Satyananda Giri and Paramahansa Yogananda. Sri Yukteshwar was an educator, astronomer, a Jyotisha , a yogi, and a believer in the Bhagavad Gita and the Bible...
. In his book, The Holy Science
The Holy Science
The Holy Science is a book written by Swami Sri Yukteswar Giri in 1894 under the title Kaivalya Darsanam. Sri Yukteswar states that he wrote The Holy Science at the request of Mahavatar Babaji...
, first published in 1894 as Kaivalya Darsanam, Yukteswar describes the Great Year as a period of time wherein the earth goes through a "complete change, both externally in the material world, and internally in the intellectual or electric world" with four rising ages and four descending ages, equal in length to one complete precession of the equinox. Other Indian scholars put the length at millions of years, a period of time unrelated to the precession cycle.
According to Giorgio de Santillana
Giorgio de Santillana
Giorgio Diaz de Santillana was an Italian-American philosopher of science and historian of science, and professor at MIT....
, the late Professor of the History and Philosophy of Science at M.I.T and Hertha von Dechend, in their book Hamlet's Mill
Hamlet's Mill
Hamlet's Mill by Giorgio de Santillana and Hertha von Dechend Hamlet's Mill (first published by Gambit, Boston, 1969) by Giorgio de Santillana (a professor of the history of science at MIT) and Hertha von Dechend Hamlet's Mill (first published by Gambit, Boston, 1969) by Giorgio de Santillana (a...
, published in 1969 by Gambit, there are over 200 myths or folk stories from over thirty ancient cultures that refer to a Great Year tied to the movement of the equinox or the motion of the heavens.
Significance in astrology
Most astrologers use a precession rate rounded to 50 arc seconds per year to derive a Great Year period of 25,920 years, the period required for the equinox to move through all twelve of the classic zodiacal signs. Some, such as Boris Cristoff prefer to round the age of one sign of the zodiac to 2100 years, which equates to a Great Year duration of 25,200 years.Footnotes