So I find out this morning that a 13th sign has been added to the zodiac.
A Minneapolis Star Tribune story earlier this week about zodiac signs quoting Minneapolis astronomer Paul Kunkle saying (correctly) that when astrologers say the sun is in Pisces, it isn’t. Kunkle also mentioned that the sun spends more time in the constellation Ophiuchus the Serpent Bearer than in the neighboring traditional zodiac constellation Scorpius. Also true. To be fair then, shouldn’t Ophiuchus be brought into the zodiacal fold as the 13th sign? Since the story first appeared, the Internet has been abuzz with folks wondering whether they should upgrade their “sign” and check out their Serpent Bearer potential.
Back in the olden days circa 1000 B.C., the Babylonians divided up the circle of the sun’s yearly path across the sky into 12 approximately equal constellations for the 12 months of the year. This system came down to us through the Greeks as the zodiac. Your sign is determined by which of the 12 constellations the sun was in on the date of your birth. My birthday is August 9, which makes me a Leo, named for the constellation Leo the Lion. Well and good … 2000 years ago.
Enter a little thing called precession. Earth’s axis slowly wobbles or precesses over a period of 26,000 years due to the combined gravitational tugging of the sun and moon. Picture a spinning top slowing down. As its spin rate drops, the axis of the top describes a little circle (wobble) in the air before eventually tipping over. The Earth’s axis describes a similar circle in the sky with a period of 26,000 years. Since the pole star is determined by where our axis points, it follows that we see a variety of different pole stars during that long cycle. Right now, Polaris in the Little Dipper sits in the hallowed spot at which our axis points, but in 14,000 A.D., brilliant Vega will occupy the position. Due to the cyclic nature of precession, Polaris will regain its North Star title in 28,000 A.D.
At the same time that the pole star is slowly shifting, precession also causes a shift in the background constellations against which the sun appears to move. Keep in mind, the constellation outlines remain the same; it’s where the sun is in relation to the background stars that changes.
The Earth’s wobble causes the sun to drift westward along the zodiac to the tune of 1.4 degrees (about three sun diameters) per century. In 2,000 years, that adds up to 28 degrees or about one zodiac constellation width.
Let’s look at an example. Since the year 1 A.D., the Earth’s wobble has caused the sun to slide westward a full constellation. Back in the glory days of Rome on January 14, the sun was in Capricornus. 2000 years later we see it in Sagittarius. 2000 years from now its westward excursions will take it into Scorpius.
The ancients were aware of precession’s effects, but today’s astrologers choose not to update their signs. As a result, the sign you were born under is only correct for a limited period of time, maybe 1000 years, give or take. My birthday sign is no longer Leo but Cancer, the zodiac constellation to the west of Leo.
Below is a listing of new dates when the sun’s in your sign based upon its true location in the sky. I’m certain it will never be adopted. Tradition you know.
* Sagittarius: Dec. 17-Jan. 20. Capricornus: Jan. 20-Feb. 16. Aquarius: Feb. 16-March 11. Pisces: March 11-April 18. Aries: April 18-May 13. Taurus: May 13-June 21. Gemini: June 21-July 20. Cancer: July 20-Aug. 10. Leo: Aug. 10-Sept. 16. Virgo: Sept. 16-Oct. 30. Libra: Oct. 30-Nov. 23. Scorpius: Nov. 23-29. Ophiuchus: Nov. 29-Dec. 17.Â
Ophiuchus is included just for fun as the 13th sign. Ophiuchus wasn’t even a contender for a zodiac sign back when the system was created, because the obvious outline of its stars lay to the north of the sun’s path. The sun started crossing Ophiuchus in 1930 when the International Astronomical Union officially fixed the current constellation boundaries. In doing so, they included a nondescript chunk of sky below the constellation’s main outline within the official border. The sun travels through this bit of celestial real estate in late November-early December en route from Scorpius to Sagittarius.
So what do you think? Should astrologers update the zodiac every 500 years or so to keep the sun in its rightful place? For me, it doesn’t matter either way since the positions of the sun, moon and planets have no bearing on either my personality or fate. That stuff’s in other hands.