Astrology is the study of celestial bodies’ effect on human affairs, personality, and natural events. Astrologists hold that all things are intertwined with the rest of the cosmos; therefore, celestial events reflect human happenings. Using this principle, they practice divination by creating elaborate prediction charts called horoscopes; natal horoscopes are most popular, centering on an individual’s personality and destiny based on time and place of birth.
The planets’ positions drive astrological predictions. To orient the heavens, astrologists utilize earth’s ecliptic. Although the earth orbits the sun, on earth, it appears the sun, planets, and stars rotate around us; the ecliptic is the imaginary disk-plane in which these heavenly bodies orbit earth.
In astrology, the ecliptic divides into 12 even pie-slice zones called the zodiac, named after the ring of constellations that line the “border” of the ecliptic. Because each zodiac occupies a twelfth of the ecliptic, the sun sends a twelfth of the year in each zone. A person’s sun sign (or star sign) is determined by what zodiac the sun occupies at his time of birth, and implies certain personality traits. For example, Taurus sun signs are considered stubborn, cautious, and dependable. Most magazine horoscopes use sun sign astrology, relying entirely on the sun sign to make personal predictions. Traditional astrologists critique this approach for ignoring the many other astrological influences.
The ecliptic also divides into 12 Houses. In natal astrology, at the time of the subject’s birth, the Houses are numbed counterclockwise from the eastern horizon. Each House governs a different aspect of life; the planets in each House when the subject is born determine his traits. For example, if Neptune – associated with idealism and personal dreams – is in the Second House – the House of Value – the subject may have idealistic (unrealistic) money sensibilities.
The positions of planets relative to each other – or aspects – are also an important consideration. For example, if two planets are roughly 90° from each other, they’re said to be square (in opposition). This represents stressful conflict between the qualities these planets govern.
When the zodiac was first defined in the Babylonian calendar (first millennium BCE), the sun appeared over the constellation Aries during March’s vernal (spring) equinox, the beginning of their year. Tropical astrologists hold firmly to these ancient parameters. However, because the earth’s axis is tilted, it’s actually wobbled away from this original position; the sun now passes through Aries about 24 days later. Sidereal astrologists account for this change in their horoscopes. Although debate between these two schools has raged for years, it seems not even the stars can tell which school – if either – is right.