The Zodiac

What the heck is it, anyway?

By: Keitha (FireWind)
Posted: Jan. 21st/99
Updated: Dec. 15th, 2001

The Zodiac is actually based in ancient astronomy. This idea conjures up images of ancient storytellers staring at the sky and making myths and constellations; and in fact this idea is right. But myths aside, the astronomy of the ancient Greeks was also based in mathematics. For example, the ancient atronomer/mathematician Eratosthenes in the 3rd Century BCE estimated the circumference of the Earth as 39,300 km around. Today, we know it to be 40,075 km around. Not bad, considering that over a thousand years later they were still arguing if the Earth was even round or not.

But down to the zodiac. "Zodiac" means basically 'circle of animals' in ancient Greek. The zodiac were the 12 ancient constellations that were roughly lined up on the path the sun takes through the sky. Imagine the Sun and the Earth in space. On the same plane (the same level) surrounding the Sun and the Earth, is the zodiac constellations. Of course we all know that the Earth goes around the sun; it usually takes 365 days. When the Earth moves around to such a point that the sun appears to be between the Earth and a given constellation, the sun is said to be 'in' that constellation. For example, the sun is in Gemini when the Earth, the Sun, and Gemini are in a straight line, and the sun is blocking Gemini from us.

To follow with Gemini for a minute, Sagittarius is directly across from it on the wheel. So at night, when the Earth is facing away from the sun, you can see Sagittarius in the sky when the sun is in Gemini. When the sun is in Cancer, you can see Capricorn in the sky, etc. It takes roughly a month for the Earth to move around the Sun enough to see the Sun on the backdrop of the next constellation. If you don't fully see this at first, don't worry, it took me a while to get it, too. But it really is quite simple once you finally manage to see it in your mind.

The reason there are 12 constellations is, of course, because the moon goes through its phases about 12 times a year. Aries is important, because at the time the zodiac was invented, the Vernal (spring) equinox happened during this sign. The rutting Ram of Aries was a fertility symbol in the beginning of spring. Likewise, Libra, the balanced scales, contained the Fall equinox. Today, the Vernal equinox happens when the sun is in Pisces. In a few hundred years, the sun will be in Aquarius while the Vernal equinox occurs. This is what people are referring to when they talk about the 'Aquarian Age'.

The Vernal equinox is vastly important in Astronomy today. Without this concept, Astronomers wouldn't be able to precisely locate stars in the sky. The Vernal equinox, as mentioned before, happens when the sun is in Pisces. On this day, both night and day are approximately equal, and the sun rises and sets exactly east and west. To make a long and potentially frustrating story short, todays astronomers use the constellation of Pisces as a stable point in the sky from which to plot other stars (but please understand I'm glossing over quite a lot here). In about 2700 CE, this point will have moved to Aquarius, since the Vernal equinox will occur at this time.

Still with me? Alrightythen... Because the signs and the constellations are slowly drifting out of phase, (The vernal equinox is in Pisces now, not Aries), the dates of the sun's passage through the constellations has changed. Below is a list of the times that the sun passes through the actual constellations. You may notice that they are a little later than the dates given for sun signs. This is because the signs are actually now west of the constellations.
 

And if you're really interested, here are the dates of when each sign contains the Vernal Equinox.

 

Please note that I am not even remotely an "expert" in either Astrology or Astronomy. For more information, please consult with a professional Astrologer or Astronomer, depending on your area of interest.