Precession proves to be a difficult topic. However, there can be no understanding of how the solar system operates without an understanding of the nature of precession. Precession is based on the measurable movement of the stars from the direction of the Winter Solstice to the Summer Solstice at the rate of about 1º of the Earth's orbit each 72 years. The Earth's orbit is used to measure the rate at which precession occurs because there is simply no other way to produce the measurement. Remember that the Earth is surrounded by the darkness of space and that the only way we have to measure its position is by the points of light, the sun and the stars, and the points of reflected light, the planets and the moons off of which sunlight reflects that appear in this darkness. When we are talking about measuring the movement of the points of light surrounding the Earth produced by stars, we have no reference point. We have to produce a reference point that will remain constant to us, while the stars appear to be moving.
One point that is always constant is the point produced by the tilt of the Earth. Because the Earth tilts with respect to the sun, the sun appears to move North and South and then back to North as the Earth moves around the sun. When the Earth is tilted away from the sun in the Northern Winter, the sun is overhead at the Tropic of Capricorn, the furthest South the sun moves, a point a little over 23ºs South of the Equator. In the Northern Summer, the sun is overhead at the Tropic of Cancer, a little over 23ºs North of the Equator. While the sun is moving North between the Summer and Winter Solstices, its passage over the Equator, whose name is derived from the equalized day and night it supposedly produces, occurs at the Autumnal Equinox. While the sun is moving South between the Winter and Summer Solstices, its passage over the Equator is called the Spring, or Vernal Equinox.
The Vernal Equinox occurs when the dark side of the planet is facing the Milky Way, the galaxy of which the Sun, with its Solar System containing the Earth is a part. The Milky Way provides a rich field of stars and thus the Vernal Equinox, which is a unique point of the Earth's motion with respect to the sun, and therefore the basis of a measuring point, was used to measure the position of the stars. The measurements over a period of centuries B.C.E. had demonstrated the movement of the stars as a degree of a circle.
The circle used at that time, however, was the orbit of the sun, which was thought to orbit the Earth. Remember that we can only measure the movement of objects in space if we have a point of reference. When it comes to whether the Earth orbits the sun or the sun orbits the Earth, we have no point of reference. Today, we know that the sun only appears to orbit the Earth. Copernicus was the first to produce a visual representation backed by tables of planetary movements that supported the notion of a sun centered solar system, but such a system was not proved theoretically until Foucault devised his pendulum in 1851 and wasn't proved factually until the advent of the space program in the early 60s.
Thus, when Hipparchus set out to determine the nature of the stars' drift in the 2nd Century B.C., he used the movement of the sun to measure precession. He not only thought the sun moved around the Earth, he thought that the sun moved North and South to produce the seasons, the Winter and Summer Solstices, and he thought that the movement of the sun across the Equator, rather than the tilt of the Earth as it moved around the sun, produced the Equinoxes.
As a result of this belief, he thought that the stars were fixed and the equinox was moving. The 360º circle he used to measure the rate of precession was the movement of the sun around the Earth, not in the familiar 24 hour cycle, nor in the seasonal yearly cycle, but in a very slow cycle that took 72 years times the 360ºs that made up the circle, or a cycle of approximately 26,000 years.
A feature of being on a planet that is immersed in the darkness of space surrounded by stars is that, making the assumption the stars are motionless allows us to use the stars to measure the progress of the Earth as it moves in relation to the sun. When we believed that the sun moved around the Earth in a yearly cycle that produced the seasons, the assumption that the background stars were motionless led to the creation of groupings of those stars to make the passage of the seasons and these groupings are called constellations.
Thus, the idea that the sun moved around the Earth in a 360º circle led to the division of that circle into twelve 30º segments, the 12 months we know today, and each of those months was marked by a grouping of stars, constellations, which appeared at sunrise during the segment. As the sun moved around the Earth, it would pass through the Houses of the Zodiac marked by specific constellations in an orderly progression. Let's imagine that we are sitting on a platform on the Great Lawn in the center of Central Park at midnight and the lights of Manhattan twinkle all around us. If we are the Earth, and the sun is moving in a circle around us, we will see it moving against the backdrop of lights We can't see the sun at night, and we can't see the backdrop during the day when the sun is up, but we can see lights just before sunrise and we can therefore use sunrise to mark the sun's position with respect to the lights. If we take groupings of lights in the 360º panorama around us and name them, then we can watch the progression of the sun as it moves around over the course of the year by the named groupings of lights.
When Hipparchus attempted to come up with an explanation for precession, he concluded that the sun was moving through the Zodiac in a direction opposite from its yearly movement. Since he was forced to use the circle of the sun's orbit around the Earth as a measuring device, he concluded that precession was a circular function of the sun's movement, that it slowly reversed its course through the Houses of the Zodiac over a period of approximately 26,000 years. Under this scenario, precession would move the Vernal Equinox from its position facing Madison Avenue on the East to a position in which it occurred at the Winter Solstice on Central Park South 6,500 years later, then on to a position where it faced Columbus Avenue on the West after another 6,500 years, then after another 6,500 years to a point where it faced Central Park North and finally, after another 6,500 years, to its original position facing Madison Avenue on the East.
In short, and this is a very important point, Hipparchus, because he believed that the movement of the sun controlled the position of the Vernal Equinox, believed that the Vernal Equinox orbited the Earth in a 26,000 cycle.
When Copernicus put the sun at the center of the solar system, with the tilted Earth orbiting the sun, he couldn't account for the movement of the Vernal Equinox. He therefore erroneously concluded that it continued to move. The subject was lost in the resulting clamor over the religious implications of removing the Earth from the center of the universe, but could not be left unexamined when Newton produced the gravitational rationale for planetary motion around the sun.
Newton was aware that the Vernal Equinox could not move around the Earth. However, he was focused more on his Theory of Universal Gravitation than the position of the Earth with respect to the background stars that made up the Houses of the Zodiac and thus he concluded that precession was produced by the wobble of the Earth on its axis.
There are three problems with Newton's conclusion.
First is the fact that the wobble occurs in the same place in the Earth's orbit. Even though the Earth orbited the sun, the sun could still appear to rise on a monthly basis in each of the Zodiac constellations. Return to our Central Park analogy and instead of ourselves on the center of the platform, we place the sun there, with ourselves orbiting it. As we revolved around the sun in a 360º circle, we would see it rise in a different Zodiac constellation every month. However, our Vernal Equinox would always be stuck facing Madison Avenue. It couldn't move. Thus, the assumed reverse motion of the sun around the Zodiac in a 26,000 cycle could never occur. Stuck facing Madison Avenue, no amount of wobble would produce a movement where the sun would rise facing Central Park South, Columbus Avenue or Central Park North. We would always be stuck right where we were, with the sun rising at the Vernal Equinox which was facing East towards Madison Avenue.
Second, wobble would produce the same apparent motion that the tilt of the Earth produced, a North South motion over the Equator rather than a motion of the planet in a 360º orbit that would move the Vernal Equinox through the Zodiac constellations. In fact, Newton produced his wobble theory simply because he knew the Vernal Equinox was fixed on the Earth's orbit. However, there is no conceivable way that wobble would allow us to view something we could only see from the opposite side of the Earth's orbit.
Finally, wobble does not provide the basis for computing a 26,000 cycle. The only way the 26,000 year cycle could be computed was by assuming that the sun moved in a 360º orbit around the Earth or that the Vernal Equinox moved in a 360º orbit around the sun, neither of which occurs in reality. Newton simply ascribed the 26,000 year cycle, erroneously calculated by the wrong assumption of an Earth centered universe, to his wobble theory.
And yet, the stars are continuing to move past the measuring point of the Vernal Equinox at a steady rate using a small enough differential in the Earth's orbit to produce a series of dots that form a straight line. The only acceptable conclusion is that the stars are moving with respect to the sun, that the sun is moving with respect to the stars, carrying the Earth along with it or that both are moving with respect to one another. Attempts to explain it otherwise fall flat.
One such explanation, that because the Vernal Equinox is an intersection of the equator of the Celestial Sphere and the ecliptic, the actual equator, the Earth is stationary on the ecliptic but moves around the Celestial Equator, is merely a complex way of saying the Vernal Equinox moves along the Earth's orbit, which it doesn't. Another explanation is that the perturbations from Jupiter and Saturn make the perihelion (basically, the Winter Solstice) orbit the sun. The definition of perturbation implies randomness, so this explanation would not produce the steadily measured motion we find in the movement of the stars past the Vernal Equinox.
All of this might simply be grist for the arcane astronomical mill but for the publication of Hamlet's Mill in 1977, a search for an awareness of a common past by Giogio de Santilllana and Hertha von Dechend. The precession they describe is a mixture of the precession of Hipparchus, with the Sun orbiting the Earth, the Vernal Equinox moving along the Earth's orbit and the Earth orbiting the sun which fixes the Vernal Equinox at a specific place in that orbit. This has led to statements that make no sense, that due to the very gradual wobble of the Earth around its own polar axis, the Earth gradually changes its relationship to the signs of the Zodiac.
This is claiming that a fixed Vernal Equinox results in a moving Vernal Equinox.
After becoming firmly embedded in the popular conscious, and after software was created that generated the North South North movement of Newton's wobble, researchers have started to attempt to date past events combining the supposed past skies as produced by Newton's wobble with the clear zodiac periods that appear in the historical record. While there is some correlation, it is due only to the fact that we are limited to 6,000 years of history and thus deal only with the Zodiac constellations strung out to the East along Madison Avenue, not with those around a circle. And using software that produces a North South to North motion, rather than the actual motion of the stars past the precessional point, further obscures such dating arguments.
Precession does not produce a measurable motion through the Houses of the Zodiac. Newton's theory of wobble does not produce a measurable motion through the Houses of the Zodiac. Any theory that produces movement through the Houses of the Zodiac does not describe precession, and wobble does not describe the slow measurable movement of the stars past the measuring point of the Vernal Equinox.
It's time to reexamine our concepts of solar system operation so that we can account for measurable precession.
Peter Bros is the author of the 9 volume Copernican Series and is President of The Far Museum of Dallas, an actual history museum, which will house its collection of 50,000 rare Eastern Mediterranean manuscripts and artifacts together with actual history displays and tours in a full-sized replica of the Egyptian Temple at Dendera to be built in the Dallas Ft. Worth area. Email:peterbros@therealskeptic.com