The Astronomy of Astrology

In order for Babylonian astrologers to be able to practice their art, charts and tables indicating the rising and setting of stars were produced. Based on their observations, it was noticed that some of the stars didn't move in the same manner as the others. Later, the ancient Greeks would give us the word that we use for these objects today, planets - derived from asteris planetai or wandering stars.

Astrology consisted of taking careful readings of the positions of the stars and planets and attempting to match their positions to large scale occurrences on earth such as religious movements, wars and earthquakes. Predicting the future of an individual was unheard of unless that person was powerful enough to have a massive effect on the world around them. Wealthy individuals poured money into astrology, helping build bigger telescopes for stargazing, hoping to obtain a clearer vision of their future. Thus astrology originally subsidized astronomy, and was a useful day job for many of the great astronomers such as Kepler and Galileo.

The two types of astrology

There are two main flavors of astrology as we know it - Western and Indian. Both types split the ecliptic plane, (the path that the sun, moon and planets roughly follow across the sky) into twelve chunks, each corresponding to the constellation which was showing in the night sky when the zodiac was first divided. Astrology centers around the positions of the sun, moon and planets on the zodiac for a particular event, the general gist being that the position of each planet effects our life on earth. A common feature in both types of astrology is the significance of the zodiac sign that is in ascension, due to the rotation of the earth, on the eastern horizon at the moment of a person��s birth. The big difference between the two types is that Indian astrology uses the sidereal zodiac which corresponds to whatever constellations are in the sky, whereas Western astrology uses the tropical zodiac which is based on dates, and has gradually become a month out of synch with the constellations themselves. This effect is caused by the precision of the equinoxes as the earth wobbles on it's axis like a spinning gyroscope. Although this happens very slowly at a rate of 1 degree per 70 years, this precision means that the constellation of Pisces now shines in the sky during the western zodiac sign of Aries.

The constellations

Although each point of light looks much the same using the naked eye, we can now look deeper into space and discover that some of these points of light aren't stars at all, but entire galaxies, so far away that they appear the same size as their cosmic cousins who together form the constellations so drawn upon by astrology today. It is romantic to think that perhaps our Sun, or even our own Galaxy, the Milky Way is a tiny dot in some fantastic alien zodiac sign. We now also realise that the constellations themselves are changing and distorting. The stars which appeared stationary to ancient astronomers are now known to move relative to each other. Although everything in the universe is moving, sometimes at vast speeds, the universe itself is huge �V and the ��apparent motion�� of the stars in human scales is very slow. In order to see most stars move you would have to take pictures which are hundreds, if not thousands of years apart. The only other way to see stars move, and reveal their actual position to the human eye will be if and when human beings leave earth to travel in space to distant stars. These interstellar travllers will see that the stars in the zodiac signs, which from earth appear to be flat and ��pasted�� on the sky, are in reality found to be located at many different distances from earth, some closer and some further away.