What Is The Zodiac?

The Zodiac, the 12 signs listed in a horoscope, is closely tied to how the Earth moves through the heavens. The signs are derived from 12 constellations that mark out the path on which the sun appears to travel over the course of a year.

In principle, dates in a horoscope should correspond to when the sun passes through each constellation. But they don't, much of the time. And a closer examination of the motion of the Earth, the sun, and the stars shows the Zodiac to be more complex than you might imagine.