Sidereal vs. Tropical zodiac and why it matters
If you’re new to astrology, you likely don’t know the difference between Sidereal and Tropical zodiacs. This post is for you!
If you’re like me and live in the Western world and know anything about astrology, you probably consider yourself an Aries (like me) or one of the other 11 signs. But what does that mean exactly? Well, for most people their “sign” means their sun sign. This is the constellation the sun was residing in the day they were born.
However, you may often hear people say that astrology is wrong because “I’m told I’m an Aries, but actually the sun was in the sign of Pisces the day I was born so let’s just throw out astrology all together”. Bill Nye “The Science Guy” has a short video saying exactly this (but with his sun sign). So why would he say that and what does it mean?
The reason this is so is due to what’s called the Tropical Zodiac. The Tropical Zodiac, the zodiac most Western astrologers use, is based on where the sun was stationed on each calendar day 2000+ years ago. This was when astrology moved from India into the “West” via moving through Zoroastrian Persia. When this happened, a big philosophical debate took hold relating to predestination vs. free will and it also led to the Tropical Zodiac. That is to say, in the Tropical Zodiac, the zodiac became frozen in the sky as the sky thousands of years ago.
Here’s the thing though, the sky isn’t fixed! The earth as you may know has a “wobble”; this is also called the precession of the equinoxes. Over the course of thousands of years the sky shifts, and the constellation the sun was once in is no longer the same on a given day! For example, I am an Aries in the Tropical Zodiac and thousands of years ago the sun was in the constellation Aries on the day I was born. However, due to the wobble of the earth, the sun is now actually in the constellation of Pisces on the day I was born, making me a Pisces according to the Sidereal Zodiac. You see, the Sidereal Zodiac actually tracks the wobble of the Earth via the precession of the equinoxes!
Incredibly, the genius rishis (enlightened sages of Vedic India) had a mathematical system in place that somehow accounted for the precession of the equinoxes! This is even more amazing when one learns the only way that is possible is either 3000+ years of very precise astronomical observations and mathematical modeling, or someone being able to observe the wobble of the Earth via satellites. This means that Jyotish, or Vedic Sidereal Astrology must be vastly older than the 2500 year old date when it was formally recorded in ancient India (see footnote below).
This incredible knowledge of the precession of the equinoxes allows Vedic Sidereal Zodiac to track the motion of the skies, so in the Vedic system I am correctly identified as a Pisces Sun. However, this doesn’t mean I’m not an Aries! You see, both systems have been developed in such a way as to maintain their own integrity, within their own system. In fact, I usually refer to myself as an Aries and in many ways I behave like an Aries. This may be due to the fact that my Moon is in Aries in both Western and Vedic systems. What’s that, your moon, you say? Yes! It turns out that not only do we have Sun signs, we have a Moon sign, a Mercury sign, a Rising (Ascendant) sign and much more!
Astrology isn’t merely horoscopes you read and laugh at in your local paper. Astrology is a deep and broad discipline that has elements of both art and science. Astrology has been largely derided in the West due to a belief in free will and also as an Enlightenment-era reaction to the Church and a rejection of spirituality and religion in favor of materialism and science. This reaction is something we still see the reverberations of in modern Western society. In India, there is often a comfortable co-existence of science and spirituality; they’re not seen as mutually exclusive. Part of what attracts me to astrology is that I enjoy the blend of art and science. I enjoy observable, repeatable phenomena and also acknowledge there is an unseen force that puts the universe into motion.
Scholars debate on the age of Jyotish, but I feel the fairest estimate is 500 BCE as the latest it was formally recorded. It is said in India that it is a minimum of 5000 years old and based on the precession of the equinoxes data. That’s a conservative estimate and a more likely date is earliest 3500 BCE and perhaps vastly older than that.
