Born and brought up in India, I knew about astrology in my younger days. I am not going to lie – I found it intriguing and interesting. Back then, the whole concept of how the constellations determined our personalities, compatibility and future filled me with awe. But as I grew up, I began to read many books on astronomy. So gradually, my belief in the system of astrology vanished. In this series of articles, I will share some of my viewpoints on this subject.
One of the key concepts of Western Astrology is the Zodiac Signs. It’s especially relevant that the concept of the Zodiac exists in both astronomy and astrology. So in this first part, I will share what I found out about the Zodiac Signs.
The Astronomy behind the Astrology
Imagine a sphere that is concentric with the Earth and has a very large radius – kind of engulfing the earth. This imaginary sphere is referred to as the Celestial Sphere in astronomy. In the below image (courtesy: Wikipedia) you can see the rotating earth engulfed in a blue sphere. This blue sphere is referred to as the celestial sphere.
Ecliptic Coordinate System
Next, imagine the apparent path of the Sun in this celestial sphere. This is called the Ecliptic. In the above image, this is denoted by the red dotted lines. Note that this path I am referring to is an imaginary one. Because it is not the Sun that moves, but the earth.
You know the earth has a coordinate system based on latitudes and longitudes to represent a location on the earth. Similarly, astronomers have invented a variety of celestial coordinate systems. They use these celestial coordinate systems to specify the positions of satellites, planets, stars, galaxies etc in the sky. So this imaginary path known as ecliptic is useful to create an Ecliptic Coordinate System. Astronomers use this coordinate system for representing the positions and orbits of objects in the Solar System. And this is also measured in latitudes and longitudes.
A constellation is a group of stars forming a recognisable pattern. Astronomers have named them after their apparent form or a mythological figure. The International Astronomical Union (IAU) is an international association of professional astronomers. It acts as the internationally recognised authority for assigning designations to celestial bodies including constellations.
So… what are the Zodiac Signs?
The ecliptic, i.e. the Sun’s path, is like an oval ring around the earth. In ancient astronomy and astrology, this is divided into twelve equal divisions of 30° each referred to as Zodiacs. Therefore, the constellations that appear in these 12 divisions are Zodiac Signs.
We can find the oldest records of astronomy in ancient Sumeria. Sumerians and Babylonians “invented” most of the zodiac signs between 2000 and 3000 B.C. These included Leo, Taurus, Scorpius, Auriga, Gemini, Capricorn, and Sagittarius. Back then, the people used these mainly to mark seasons and periods for farming activities.
Later on, up until the 18th century, astronomers continued to use the zodiacal signs for measurements. Mainly it was for measuring the ecliptic longitude, i.e. the position of the Sun. For example, to specify the position of an object that was 19.933° east of the sign Leo one would write – 19° 55′ 58″. However, in modern astronomy, astronomers write the longitude as 139° 55′ 58″.
But somewhere between these two periods the usage of zodiac signs became popular for deciphering human affairs and world events. Astronomical mythologies may have been one of the reasons for the popularity of this.
Does Astronomy support Astrology?
Here are a few thoughts where I found contradictions between astronomy and astrology.
Fact #1: Your Zodiac Sign based on your birth day is not correct.
Astrologers associate zodiac signs with a person based on their birth date. This is based on the position of the Sun in relation to the Earth and the zodiacal constellations. But the 12 constellations that make up the zodiac signs vary widely in size. So the Sun is between the Earth and each zodiacal constellation for varying periods. Contrary to popular beliefs, it is not exactly 28 or 30 days each. While for larger constellations, like the Virgo, it can be up to 44 days. But with the smallest constellation like the Scorpius, it is only 7 days. Therefore, the dates mapped against each zodiac sign are technically wrong. So just because you are born between October 24 and November 22, doesn’t make you a Scorpio. Because the Sun is in Scorpius only for 7 days.
Fact #2: The Sky evolves every day.
In the 2nd century, Ptolemy had listed only 48 constellations in his Almagest. But as of date, there 88 known constellations. However, the ecliptic path, i.e. Sun’s path, is only through 13 of these. Yes 13, not 12! This additional constellation, that does not have an astrological Zodiac Sign yet, is Ophiuchus or Serpentarius. Like all the other 12 Zodiac signs, even this one comes with a mythology of its own. Ophiuchus is in the shape of a man holding a serpent and means serpent bearer.
Astronomers have reported that in a few hundred years the ecliptic will no longer pass through Scorpius. But it may include the constellation of Orion.
Astrologers claim that the alignment of the Sun, Moon, Earth, other planets and zodiac signs affect human affairs and character. However, the discrepancies between astronomy and astrology show that astrology is not true to science. And also, associating something so ever-evolving as the celestial space with human affairs makes no sense. Therefore, it must be the human brains trying to form patterns and connections, where none exists.