Precession of the Equinoxes
What is it, and how does it affect Astrology?
The argument of the Precession of the Equinoxes is one frequently made by those opposed to astrology, who claim that it ‘disproves’ astrology and renders it invalid. This is perhaps best illustrated by an answer we gave in response to a recent question:
“How can astrology be valid when the points in space you refer to are no longer in the same positions as they were thousands of years ago? Doesn’t that invalidate all of this horoscope stuff?”
I think the phenomenon to which you are referring is known as the Precession of the Equinoxes. Because of this phenomenon, the zodiac signs do not now correspond with the constellations of the same name. This point is often made by astronomers and others to apparently ‘prove’ that astrology cannot ‘work’. In actual fact, astrologers are well aware of the Precession and its effects.
The point referred to by Astronomers as the vernal equinox, and by astrologers as 0 degrees Aries is in fact seen each year from the earth as slightly before its previous year’s position against the background of the constellations. This is caused by a wobble in the earth’s axis, caused by unequal gravitational pull of the Sun and the Moon on the earth’s surface. The point referred to as 0 degrees Aries is actually seen from earth now as being in the constellation of Pisces. Aha, the sceptics say – that proves astrology is nonsense, you say that someone’s sun is in Aries when in fact that point in space is now in Pisces, right? Wrong.
It is vital to understand the difference between constellations and the zodiac. Much confusion arises for the lay person because the constellations have the same names as the signs of the zodiac, but they are not the same thing. The groups of stars marked on charts as constellations are not actually groups at all. What we see from earth is the grouping of several points of light, some from points many millions of light years away, and others from much further even that that. These ‘groups’ have no definite boundary lines as such, but are conveniently classified by man into constellations.
At the time that these constellations were being named and their name becoming known in the public arena, the 30 degrees of ecliptic, starting from the vernal equinox, was called Aries and the constellation that appeared as its background was therefore also called Aries. No precise date can be given for this, but the precession of the equinoxes was not discovered until 134 b.c by Hipparchus.
It is the vernal equinox point (0 degrees Aries to an astrologer) that appears from earth to move further back each year – the constellations remain in the same positions. However, the signs of the zodiac are and always have been counted in 30 degree segments from the vernal equinox point. Aries will always be the first 30 degrees of the ecliptic (with the others signs following on), and therefore will, each year, appear slightly further back against the background of the constellations.
So, the fact that the point we call 0 degrees Aries is now seen from earth as being against the background of the constellation of Pisces has nothing whatsoever to do with astrology – it neither proves nor disproves anything. When people assume that it somehow ‘disproves’ astrology, they have not understood the difference between the astronomical constellations and the astrological zodiac. It might help to understand if you can think of the signs of the zodiac as being a kind of shorthand to describe the various degrees of the ecliptic (remember, this always begins at the vernal equinox, and it’s starting point does not change but it appears to against the background of the constellations). Each 30 degree segment of the ecliptic has certain astrological significance, but we don’t actually need to call them Aries, Taurus and so on at all. It is just easier to say (for instance) that in a particular chart Mars is at 3 degrees Cancer rather than have to say it is at 93 degrees of the ecliptic.
I hope this answer has made things clearer for you. It is quite a tricky concept for the non-astrologer to grasp, but basically you should always remember that the signs of the zodiac and the astronomical constellations may share names, but are not the same thing!