Astrology
Astrology can be said to be the search for meaning in the sky or the connecting of celestial phenomena with human interest. Since pre-history people have stared up at the vast sky and its complex and awe-inspiring wonder and sought meaning. The stars, it seems, look down at us peacefully and regard our wordly existence from aloft and at some point in our human evolution we stared back up and recognised meaning and inspiration from the sky and all the phenomena it contained. Ultimately then, astrology can be said to be the searching or expecting of meaning from the sky itself, and the celestial phenomena described there.
Newspaper Horoscopes
It can be tempting in the modern world to associate astorlogy with sun-signs, sometimes referred to as star signs or zodiac signs. We can pick up nearly any newspaper and flip to the relevant section to find short, sometimes humourous, sometimes cryptic or inspiring paragraphs on what to expect for a given sign - these short paragraphs are often called horoscopes. If I'm a Capricorn, that is, Capticorn is my sun-sign, I might learn that I should be careful of arguments with an authority figure, and if I'm a Pisces, I might learn that this is a good time for love. For many people this is exactly what astrology is, short columns in a newspaper that people relate to. But really astrology is a much broader, not to mention older, quest for meaning from celesetial phenomena that is in many ways dependent upon the culture of the individual and the connetion and conversation they have with their place in the universe.
Where does it come from?
In practically every culture since civilisation began, people have looked up to the stars in search of meaning and made sense of the sky as they saw it. The roots of Astrology in the western world at least reach back through pre-history with great influence coming from Mesopotamia (modern day Iraq, Kuwait and part of Turkey and Syria), Egypt and the Greeks. If we respect the definition of astrology as the relating of celestial phenomena with human interests or the search for meaning in the sky, then in this sense, astrology is older than history, in that the first time a cave dweller looked to the sky to divine meaning, he was an astrologer and the act of his search was a primitive astrology. But typically the complex system of astrology we have today involves charting the exact positions of planets, stars and other points and this system derives mostly from Mesopotamia, Egypt and Greece, with notable mentions from the Persians and Indians.
The Zodiac
As astrology became more systemised through western culture, it became apparent that the planets, those 'stars' which move through the sky over time, moved along a narrow part of the sky which we now refer to as the ecliptic. They divided up this ecliptic into 12 sections known as zodiac signs, and all the planets, including the Sun and Moon (which are referred to as planets for astrological purpsoes), move through the zodiac in an apparent cicular fashion at different rates. The recording and understanding of time is intricately linked with astrology and in many ways astrology can be said to be the understanding of the meaning of a given moment of time for human or wordly affairs. The Moon, which takes roughly 28 days to compete its course through the zodiac, is used as the base of a unit of time from which we get a Month. The Sun, which takes about 365 days, is the basis of our year, and all the other planets have less obvious but nonetheless important cycles of various lengths of time, Saturn for example being roughly 28 years and Uranus being about 84 years.
The Houses
To an observer of the sky the Sun, the stars and all the planets appear to move around us as observers here on earth. We know now of course that the earth in fact revolves around the Sun, and yet from our perspective it is the other way around. As the earth rotates on its axis over the course of a day, it likewise appears that the sky, carrying the Sun and stars, rotates around us. We notice the Sun appearing to rise in the morning, rising steadily higher until around noon, and eventually setting in the evening. We know that this is a product of the earth rotating on its axis and not that the Sun is actually moving around us, but this apparent phenomena and others like is still a meaningful and significant cycle of our lives - around which much of our daily life, even in the modern world of artificial light, is based. In fact our very biology reflects this cycle of sunlight in our circadian rhythms. In addition to dividing up the sky and the path of all the planets through their cycles by the zodiac, ancient observers also recognised the important meaning of the apparent movement of the sky over the case of a day (giving rise to sunrise and sunsets, but also the rise and set of all the planets and stars) and similarly divided up the sky around us into 12 sections, known by astrologers, as the 12 houses.
How do you use it today?
Astrologers today typically use the position of planets in the zodiac, coupled with the angular relationship those planets have with one another contextualised by the 12 houses as the basis of their astrology alongside some important astronomically meaningful points. Each sign has a particular meaning or set of meanings, as does each planet and house as well as the type of geometrical angle each planet makes to one another - these angles are called 'aspects'. With this in mind there are a myriad number of interpretations one could make from an astrological chart (a visual diagram of all this data which is unique for a given moment in time at a given location on earth).