Stories like this have been circulating in the news media like wildfire over the past few days as astronomers discover something that astrologers have known for nearly 2000 years, that the zodiac that we use in Western astrology does not line up with the current placement of the constellations.  This is due to what is called “precession,” in which due to the earth’s wobble the relationship between the earth and the stars changes over a “Great Cycle” of 26,000 years.  This is why every 2160 years or so we go through another zodiacal age, like the transition from the Age of Pisces to the Age of Aquarius that we are in right now.

You can read more about the science of precession here.

Astronomers will be disappointed to learn that this debate has raged through astrological communities ever since the phenomenon of precession was discovered sometime around 130 bce.  The astrology that is typically practiced in the West is called “tropical” astrology which is based on the seasons and the earth’s relationship to the Sun.  Another branch of astrology originated in India and is called “sidereal” astrology which relates to the stars rather than the Sun.

Some people like to call the zodiac “star signs,” and while they are incorrect in terms of Western astrology, in which signs are called “sun signs,” the terminology “star signs” is accurate where sidereal astrology is concerned.

The astrological pantheon that we call the zodiac is a symbolic system.  The constellations do not align into nicely divided 30 degree sections as they do around the birthchart, and as many of these news articles mention there is a 13th constellation that the Sun passes through on its trip around the Sun called Ophiuchus.  This last idea has given rise to the question about whether the zodiac should have 13 signs rather than 12.  These are concepts that for many years have caused astronomers to dispute the validity of astrology.

Astrology is not astronomically correct.  Planets don’t really move backwards, and the earth isn’t the center of the solar system.  But that is how we observe the planets astrologically, and we observe them against a backdrop of symbols that are named after the constellations that form the backdrop of our observed world.

When I first started using software that can switch between the two zodiacs in the flip of a switch I tested the sidereal zodiac and found it to be inaccurate in my work.  Occasionally I have a client from India who wants to know about the Sidereal/Tropical debate, and they generally agree that the signs used in the Tropical system are more accurate for them.  You will read in the comments here that Vedic astrologers do not use the Sidereal zodiac in the same way that Western astrologers do, and there are many other techniques used by Vedic astrologers that are not included in Western astrology.

In the tropical zodiac, the cardinal points line up with the changing of the seasons.  This is true in the northern hemisphere AND the southern hemisphere, although the seasons of course are reversed in the southern hemisphere.  For example, zero degrees Aries marks the Vernal Equinox in the tropical system, and zero degrees Libra is at the Autumnal Equinox.  In my work with clients in the southern hemisphere, despite the fact that Aries is actually the Autumn season, Aries works exactly the same way, and so does Libra.

As we practice it in the West, astrology is a symbolic system largely credited to the work of Ptolemy whose “Tetrabiblos” was written about 300 years after the phenomenon of precession was discovered, but when the zero degree Aries point was still aligned with the Vernal Equinox according to Rob Hand’s excellent article.  Rob also points out that there is evidence from translations of other works that the Tropical zodiac was favored by the Greeks back to the fourth century bce.

It’s gratifying to see astrology discussed in the mainstream media, and ABC News has even printed a retraction (sort of) to the story.   Our own Matthew Currie was quoted in this nice article on Salon.com.

So don’t worry – your zodiac signs have not changed.  The news media is just catching up to astrologers.