In this post, we are going to analyze about the popular myth that Astrology supports geocentric theory, i.e earth is the center of the solar system with Sun and other planets revolving around earth. With this single mis-interpretation, many come to the conclusion that Astrology is not scientific. I would like to stress the point from the earlier post that Astrology is the study of planetary influence on human life on earth. Hence earth is taken as the point of observation. This has lead to the myth that astrology supports geocentric theory. As an student of astrology I strongly believe that the ancient seers on India who authored Astrology, who could calculate planetary positions for past, present and future, who had divine knowledge; certainly could have known that planets including earth revolved around the Sun. But science demands reason, logic and evidence. This article is dedicated to all those science lovers who are willing to analyze, think logically and decide for themselves.
Let us look deep into the horoscope and try to figure out what was the understanding, our ancient Astrologer had about the solar system. Horoscope is nothing but the position of planets as seen from Earth(which is why you see Earth is marked in the center of the horoscope shown below) at a particular time mapped in a frame of reference called Zodiac. For info on the Zodiac, please refer the previous post. Earth is the point of observation or the point where humans are located, hence it is completely logical that for the study of Planetary influence on human life, Earth is taken to be the center point of the horoscope, but that itself doesn't mean that other planets are revolving around the Earth.
The definition of Geocentric model say that the “Earth is the center of the universe, and that all other objects orbit around it. The stars, sun, and planets appear to revolve around the Earth each day”. Firstly, in Astrology Earth is the center of observation and not the center of universe. Secondly none of the planets in a horoscope complete one revolution around the zodiac in a single day. Let us take Sun for example, if Sun was revolving around earth, by observation through naked eye we know that Sun travels around the east to west in half a day and come back to eastern horizon the next day morning. Hence Sun should take one day to travel around the earth, which is what Geocentric theory says. But in a horoscope as illustrated above(Click on image to enlarge) casted for two different dates, that is not true, for Sun to come back to the same point in Zodiac, it take one year. Hence it is obvious that Astrologer were aware of the fact that either Earth takes one year to revolve around the Sun or Sun takes one year to revolve around the earth, which we haven’t concluded yet. In fact none of the planets in a horoscope completes a full round in one day.
The above table compares the period of revolution of planets around Sun and in a zodiac as observed from earth which is the horoscope. As you can see that for outer orbit planets(compared to earth) the period of revolution around Sun and in horoscope matches exactly. For inner orbit planets there is a slight deviation which we will see later. The fourth column is very interesting. All planets in horoscope moves in the clockwise direction, but while in retrograde motion, they move in the reverse direction for certain period of time and then continue to move in their usual clockwise direction. You can imagine retrograde motion to an overtaking car, while overtaking with respect to the speeding car the slower car appears to move backward. In a circular/elliptical revolution, if for example Saturn were to revolve around Earth, there is no possibility of retrograde motion however elliptical the path may be. Saturn could be seen moving slower or faster at apogee and perigee but never in the reverse direction. Retrograde motion is possible only when there is a relative motion between two objects revolving around the third object, which proves beyond any doubt that Astrology doesn’t fit into Geocentric theory. It is interesting to note that only Sun and Moon doesn’t have retrograde motion as seen from Earth, because one is revolving around the other object.
Outer orbit planets(Saturn, Jupiter, Mars) have retrograde motion once in year when they are exactly opposite to Sun in the horoscope, which clearly shows that they are revolving around the Sun. Recalling the fact that Earth is in the center of the horoscope, when Saturn is opposite to Sun in the horoscope means; Sun, Earth and Saturn line up in a straight line. We also know that the outer orbit planets takes longer time to revolve around the Sun. Hence when Earth which is moving faster compared to the outer orbit planet, overtakes Saturn momentarily Saturn appears to retrogate(move backward) as seen from Earth.
Let us come to Mercury and Venus. Astrology calls these planets as inferior orbit planets or inner orbit planets. If you take a horoscope for any point in time, we can always notice that Mercury is within 60 degrees from that of Sun and Venus is with-in 90 degrees from Sun. Also, if we observe the position of Mercury, Venus and Sun for different date and time in a horoscope, we can observe that Mercury and Venus are moving to and forth across the Sun. The too and forth movement across the Sun clearly indicates that Mercury and Venus are revolving around the Sun. That is the reason why as seen from earth(Column-3), the period of revolution of Mecury and Venus is approximately 1 year coinciding with Sun’s movement. If I am able to understand this, I don’t believe that our super intelligent Astrologers couldn’t.
Last and interesting is our Moon. Moon can be understood to be the closest object to earth by it mere size as seen from Earth. Moon doesn't have retrograde motion, hence it can’t be an outer orbit planet. Moon doesn't go too & forth across Sun, hence it can’t be an inner orbit planet. Moon is the fastest moving object in the horoscope. Moon revolving around earth can be inferred from the fact that Lunar and Solar eclipse occur within a gap of 15 days, i.e for Moon to come from behind the Earth to between earth and Sun it takes 15 days, and for one complete revolution around earth take 30 days as can be seen in the horoscope.
Now we know that Earth has a relative motion and to calculate the position of a particular planet in future, you need to know, not only the motion of the other planet but also that of earth. Observing Sun and Moons movement from Earth is straight forward, because we are dealing with bilateral movement of two objects (Sun-Earth, Moon-Earth). But when dealing with Mecury, Venus, Mars, Jupiter and Venus, we are observing the movement of two objects (eg Mercury revolving around Sun) from a third object which is Earth, hence the complexity of calculations increases, since for calculating the movement of Mercury(as seen from earth), the movement of earth should also be taken into consideration. Our Astrologers have mastered all these movements and were able to calculate the position of planets as seen from earth for any point of time in past, present and future. How were they able to do this, without a telescope or any other equipment, is it possible without deep understanding of the Solar system? Whether to call it mystic science or divine knowledge is up to you.
To summarize, astrology perfectly fits into the heliocentric model of Solar system. Horoscope focuses movement of all objects with reference to Earth, incorporating the knowledge of movement of planets around Sun including that of Earth.