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Gravitational torques from the Sun and Moon on the Earth's equatorial bulge cause the Earth's axis of rotation to precess about the orbital plane. The period for the Earth's counterclockwise general or axial precession of the equinoxes due to this has recently been refined to 25,694 years. The 25,694 year period comes out of calculations of the precessional constant of 50.417262” per year in the Milankovitch theory of paleoclimates (see the paper Berger, Loutre, Lasker, 1992 "Stability of the Astronomical Frequencies Over the Earth's History for Paleoclimate Studies", Science, 255, 560-6 and Encyclopedia of Planetary Sciences, Chapman & Hall, 1997, pp 494-495, 568). Graham Hancock and other authors give wrong values for the Earth's general precession of the equinoxes. The general precession of the equinoxes means that the equinoctial and solstitial points appear to move counterclockwise against the fixed stars by an average of 1° every 71.28 years. At the same time, the pull of gravity by the other planets causes the Earth's orbital plane or ecliptic itself to precess (relative to distant galaxies) in a period of 71,000 years and taken together these two motions cause the Earth's obliquity (the angle between the plane of the Earth's equator and orbit around the Sun) to oscillate with a period of 38,830 years between a minimum of 22.2° and a maximum of 24.2°. This causes the equinoxes to not precess linearly with time. In 7135BC the equinoxes were precessing at their minimum rate of 73.75 years per degree, while in 26,550BC they were precessing at their maximum rate of 68.8 years per degree. The general precession of the equinoxes appears to be ultimately linked into the entire planetary system and is also exactly in resonance with important planetary and lunar periodicities (eg for the technically minded, 25,694 years = 2010 × 12.7830-year Neptune-Jupiter Lap = 1425 × 18.03-year lunar perigee-syzygy tide cycle or Saros cycle, a cycle of great importance in terrestrial oceanic tides). These Solar System wide orbital resonances take a long time to be set up and the commensurabilities they display are a good measure of the stability of the dynamics of the Solar System and strongly indicate against things like Zecharia Sitchin's mythical twelfth planet. The Solar System had a very chaotic start and has evolved into its current dynamically stable situation over a long time and the small amount of chaotic dynamics that still exists in the Solar System will be eventually eliminated but this in no way diminishes what was stated in the previous sentence. The Sumerians knew about the precession of the equinoxes in the fourth millennia BC. 3,200 years ago, the Sun was in the constellation of Cancer at the northern summer solstice and hence the term Tropic of Cancer for the latitude where the sun is overhead on that date. Due to the precession of the equinoxes, the solstices no longer occur in the constellations of Cancer and Capricorn as they did 3,200 years ago, which means that the Tropics of Cancer and Capricorn are now misnamed. Today they should be called the Tropics of Taurus and Sagittarius and because of changes in the Earth's obliquity they are creeping towards the equator at the rate of 4cm/day. On 22 December 1989 the June solstice - the point on the ecliptic at celestial longitude 90° - moved across the constellation border from Gemini to Taurus, two constellations off of its "original" position (see the article "The Earth's Shrinking Tropics", Sky & Telescope, June 1998, pp 36-38).
The following excerpt comes from page 47 in the chapter on "Astrological Cycles" in Moira Timms' book, Beyond Prophecies & Predictions, Ballantine Books, New York, 1994:
"If a star map is superimposed over the Earth with the pole star placed over the terrestrial North Pole, we have a celestial clock making one revolution daily. The noon point of that map (like Greenwich) is the Great Pyramid of Giza. Thousands of years ago, Egypt was known as the Land of Khem. The Khema were a group of seven major stars (in the constellation of Taurus), known today as the Pleiades. If the map is placed with the Khema over the Land of Khem (Egypt)- specifically, directly over the apex of the Great Pyramid - then Taurus falls over the Taurus Mountains of southern Turkey; Ursa Major, the Great Bear, rambles over Russia; the head of Draco the Dragon coils up over China; Orion (the warrior) over Iran/Iraq; Aries the Ram over Rome, and Capricorn (identified with the god Pan) falls over Panama, Panuco, and Mayapan (the old name of the Yucatan). Aquila the Eagle spans the United States. The analogies are obvious, and quite impressive. This is one of the clearest examples of the law of "As Above, So Below".
Those who designed and built the Great Pyramid understood this. As the central geodetic point and key node of the planetary grid, the Pyramid was constructed at a time when the Pleiades paused in the midheaven, directly above its apex. This enabled the descending passage of the Pyramid to be directly aligned with, and illuminated by, the pole star, indicating true North."
The ancient Egyptians believed that Egypt was made in the image of heaven and that a cosmic Egypt existed in the sky which their souls could reach after their earthly existence. The big problem with Moira Timms' writing is that the ancient Egyptians had very different star groupings to what we now have. The later Greeks had very different star groupings, which we basically have today. When the Greeks took over Egypt they introduced their version of star groupings to Egypt which the Egyptians adopted to their own ways as in the Denderah zodiac.
Above I've made references to astrology. The zodiac is a band of sky lying 9° on either side of the ecliptic, the plane of the Earth's orbit and of the Sun's apparent annual path. The orbits of the Moon and of the principal planets (except Pluto) lie entirely within the zodiac. The Egyptians and Sumerians knew the constellations around the zodiac and of precession and this was later systematised by Greek astrologers. The origin of the term zodiac - which is from the Greek zodiakos kylos or "circle of animals" or ta zodia, "the little animals" - remains unknown (five of the 12 zodiacal names are not animals). Twelve was the base number for Mesopotamian angular measurements in astronomy and for time also, with 60 being the base number for mathematics also being used in other angular measurements and for time also, which is the basis for our current time and angular measurements. Babylonian texts dating to 700BC show that the ecliptic was then divided into irregular zodiacal constellations. West Africans and native Americans divided the zodiac into 13 parts. In Celtic astrology there are 13 astrological signs. The oldest record of the zodiacal astrological signs as such is a cuneiform horoscope from 419 BC, when any astronomer would have been primarily an astrologer, and these show that the sky was by then divided into 12 equal parts of 30° each (see the paper Gurshtein, 1997 "The Origins of the Constellations", American Scientist, 85, 264-273). However, around 450 BC Oenopides (b. c 490 BC in Chios, Greece - d. about 420 BC) is said to have discovered that the ecliptic made an angle of 24° with the equator, which was accepted in Greece until refined by Eratosthenes in around 250 BC. Some scholars accept that Oenopides discovered that the ecliptic was at an angle but doubt that he measured the angle. Greek sources attribute the discovery of the ecliptic to Oenopides but whether he learnt of the 12 signs of the zodiac from scholars in Mesopotamia or whether his discoveries were independent Greek discoveries is unknown and a parallel development in both Greece and Babylon should not be excluded. For convenience the zero point or origin was taken to be the point at which the north-bound Sun crosses the celestial equator from the austral to boreal hemisphere. In those days this became known as the first point of Aries, marking the vernal equinox or the beginning of the northern spring. Again for convenience, the 12 sectors were given names, and those names were, not unreasonably, taken from the nearest zodiacal constellation, the constellation Ophiuchus, the Serpent Holder, being omitted in this process because the majority of astrologers say that it appears to not have any influence astrologically (there are a minority of astrologers who disagree with this). As I've written above, the constellation Ophiuchus is associated with the healer Asclepius, son of Apollo, whose emblem of entwined serpents has long been a symbol of the medical profession. It's interesting to note that many of the constellations and asterisms that date to antiquity are often made of seven stars, the number seven having a prominent place in mythology. Perhaps some of the earliest constellations were collections of the seven brightest stars in a sky region. In Western astrology, astrological signs referred then and now to the sector of the sky and not to the nearby constellation. While precession has shifted the constellations along the ecliptic, this has no significance for Western astrologers; the origin is still that easily defined point, and the sectors still relate to that point. The 13 constellations themselves around the zodiac don't occupy equal parts around the zodiac. This has led to a major departure of method between Indian astrology, which has stayed with a fixed zodiac pegged to the actual constellations, and Islamic/Western astrology, which moves its zodiac with the spring equinox point. Astrologers suggest that both zodiacs, moving and fixed, have their own relative orders of symbolic truth. To see what is actually going on the sky, below in a table are the dates and durations that the Sun will reside within the boundaries of each constellation around the zodiac in the year 2000. Precession causes these dates to slip about one day later every 70 years, which is evident in the table.
|Constellation||Traditional||Actual (2000)||Days Sun Is In|
|Capricornus||Dec 22 - Jan 21||Jan 21 - Feb 16||26|
|Aquarius||Jan 22 - Feb 21||Feb 16 - Mar 11||29|
|Pisces||Feb 22 - Mar 21||Mar 11 - Apr 18||38|
|Aries||Mar 22 - Apr 21||Apr 18 - May 13||25|
|Taurus||Apr 22 - May 21||May 13 - Jun 22||39|
|Gemini||May 22 - Jun 21||Jun 22 - Jul 21||29|
|Cancer||Jun 22 - Jul 21||Jul 21 - Aug 10||20|
|Leo||Jul 22 - Aug 21||Aug 10 - Sep 16||37|
|Virgo||Aug 22 - Sep 21||Sep 16 - Oct 31||45|
|Libra||Sep 22 - Oct 21||Oct 31 - Nov 23||23|
|Scorpius||Oct 22 - Nov 21||Nov 23 - Nov 29||6|
|Ophiuchus||Nov 29 - Dec 18||19|
|Sagittarius||Nov 22 - Dec 21||Dec 18 - Jan 21||34|
The above table comes from the article David Hasenauer, "What's Your Sign", Sky & Telescope, June 1998 p10. It can also be inferred from the above table that the beginning and ending dates of each astrological great Age is a moot point. There is a big divergence between what the equal division of the sky into 12 sectors and what is actually happening in the sky suggest for these dates and the beginning and ending dates for each astrological great Age is a matter of debate amongst astrologers. Modern astronomers recognise 88 constellations in the northern and southern skies, all of which have precise boundaries - they are not merely star patterns.
There is plenty of evidence showing how Egypt responded to the different zodiac ages due to precession. There was a shift of symbolism from the Ages of Gemini, the Twins (6400BC - 4240BC), to Taurus, the Bull (4240BC - 2090BC), to Aries, the Ram (2080BC - 80AD). Egyptians applied different means and modes of expression for each zodiac age, which were based upon the inherent specific nature of each age.
An excellent, very well researched and balanced book on this topic that I have used a lot above is Giza: The Truth - The People, Politics and History Behind the World's Most Famous Archaeological Site by Ian Lawton and Chris Ogilvie-Herald, Virgin, 1999. I have my own thoughts on all this.
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Last modified 28 October 2001.