Sony Simon Live. Love. Learn.
Being 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. The whole concept of how your personality, your compatibility with others around you and your future was determined by constellations filled me with awe. BUT… I grew up, learned science at school, read many books on astronomy and 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 aspects of Western Astrology is the Zodiac Signs. The Zodiac exists in both astronomyAstronomy is a natural science and is the study of celestial objects like stars, planets and galaxies. and astrologyAstrology is the study of the movements and relative positions of celestial objects as a means for divining information about human affairs and world events.. So in this first part, we will look into the Zodiac Signs and compare and contrast the astronomical and astrological sides of these celestial objects.
The Astronomy behind the Astrology
Celestial Sphere
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. Now note that the path I am referring to is an imaginary one. 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, there are a variety of celestial coordinate systems that were invented so that the positions of satellites, planets, stars, galaxies etc can be specified. So having 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.
Constellations
A constellation is a group of stars forming a recognisable pattern and is traditionally named after its apparent form or identified with 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 eclipticThe apparent path of the Sun in the celestial sphere. is like an oval ring around the earth. In ancient astronomy and astrology, this is divided into twelve equal divisions of 30° each. These divisions are referred to as the Zodiacs. The constellationsConstellation is a group of stars forming a recognisable pattern that is traditionally named after its apparent form or identified with a mythological figure. that appear in these 12 divisions are referred to as the Zodiac Signs.
The oldest records of astronomy can be found in ancient Sumeria. Sumerians and Babylonians “invented” most of the zodiac signs such as Leo, Taurus, Scorpius, Auriga, Gemini, Capricorn, and Sagittarius between 2000 and 3000 B.C. But it is believed that these were mainly used to mark seasons and periods for farming activities.
Later on, up until the 18th century, the ecliptic longitude was commonly measured using twelve zodiacal signs. 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, the longitude is written as 139° 55′ 58″.
But somewhere between these two periods the usage of zodiac signs became popular divination tools. 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 astronomyAstronomy is a natural science and is the study of celestial objects like stars, planets and galaxies. and astrologyAstrology is the study of the movements and relative positions of celestial objects as a means for divining information about human affairs and world events..
Fact #1: Your Zodiac Sign may not be 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 and not exactly 28 or 30 days. With larger constellations like the Virgo, it can be 44 days. But with the smallest constellation like the Scorpius, it is only 7 days. This means that the dates mapped against zodiac signs are astronomically-speaking incorrect.
Fact #2: There are more than 12 constellations and the sky will continue to evolve.
As of date, there 88 known constellations. The ecliptic path is through 13 of these – yes, 13! There is a new one called Ophiuchus or Serpentarius. Like all the other 12 signs, even this one comes with a mythology of its own. Ophiuchus is in the shape of a man holding a serpent.
Astronomers have reported that in a few hundred years the ecliptic will no longer pass through Scorpius but will also include the constellation of Orion.
Conclusion
Many astrology believers claim that the alignment of the Sun, Moon, Earth, other planets and zodiac signs affects human affairs and character. However, the discrepancies between astronomy and astrology show that astrology is not true to science. I think associating something so ever-evolving as the celestial space with human affairs is just human brains trying to form patterns and connections.