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Precession of the Equinoxes

by: John Michael Greer

A slow shift in the positions of the Earth’s axis relative to the sun and the fixed stars, precession is the source of a great deal of myth, speculation, and esoteric theory. The Earth’s axis is tilted at an angle of just over twenty-three degrees relative to its orbit around the sun, and at this period of history its northern end points toward the star Polaris. Over long periods of time, though the direction of the axis turns in a slow counterclockwise circle. As a result, the pole star gradually changes over time. So do the apparent positions of the sun among the stars at the solstices and equinoxes, since these are determined by the relation between the Earth’s angle of tilt, on the one hand, and the plane of its orbit around the sun on the other.

Estimates vary concerning the actual length of the cycle, but the traditional figures—25,950 years to complete one full circle—is close to modern guesses. At this rate, the points of the equinoxes and solstices slip backwards one degree along the zodiac every seventy-two years.

These changes have an enormous impact on the patterns of the night sky. Four thousand years ago, when ancient Egypt and Sumeria were flourishing, the pole star was not Polaris but Alpha Draconis (a star not far from the handle of the Big Dipper), and on the day of the spring equinox, the sun was in the constellation Taurus. At present, the Earth’s north pole points to Polaris and the sun rises in the early degrees of Pisces at the spring equinox; in another four thousand years or so, the pole star will be Alpha Cepheus, part of the house-shaped constellation on the other side of the sky from the Big Dipper, and the springtide will rise near the border between Capricorn and Sagittarius.

The current consensus in the world of official scholarship is that precession was first discovered around 128 B.C.E by the Greek astronomer Hipparchus. A persistent minority of scholars, though, has pointed out that this claim is not only unproven but unlikely. In ages when the movements of the stars were used to track the seasons and predict times for successful hunting and gathering, or for planting and harvesting crops, changes caused by precession would have become apparent within a relatively small number of generations.

These scholars have argued that astronomical lore played a central part in mythology, since in cultures without writing, mythic narratives offered the one sure way of passing on information from generation to generation. A strong case can be made that certain features found in myths all over the world are the remnants of an ancient language of astronomical symbolism with deep ties to religion and spirituality.

Even those who accept the Hipparchan discovery of precession have come to admit that a certain amount of precessional lore may have had an important role in ancient religion. In particular, the otherwise obscure symbolism of the Mithraic Mysteries has been shown to make perfect sense when read as a response to precession.

Outside the realm of official scholarship, precession has played a much more significant role in theory and symbolism. Comparisons between the sun’s motion around the zodiac and the much slower movements of precession led in ancient times to the concept of the precessional cycles as a Great Year. The twelve months of that year marked by the passage of the point of the spring equinox through each of the twelve zodiacal signs in turn.

The concept has been the most persistent and widespread form of precessional symbolism in the Western occult traditions. Christian symbolism has routinely been interpreted in precessional terms; Pisces, which took over the spring equinoctial point around the time of the birth of Jesus, and Virgo, which took over the autumn point at the same time, are reflected in the fish—symbol of the earliest Christians and the Virgin Mary. The Age of Aquarius so heavily popularized in the Sixties is simply the month of the Great Year into which we are now gradually moving, as the equinoctial point shifts out of Pisces and into Aquarius.

Discussions of precession in occult sources often combine or confuse precession with various other real or hypothetical cosmic cycles, and with changes in the angle of tilt of Earth’s axis—another major concern of occult theorists in the nineteenth century. A simple lack of astronomical knowledge seems to be behind many of these confusions.