Due to slight changes in the movement of the Earth around its axis, the positions of the stars in the sky relative to the
equinoxes and
solstices slowly change in what is called the
Precession of the Equinoxes. In the common Western form of
astrology, which uses the Tropical zodiac, the Vernal Equinox always is associated with 0 degrees of the sign
Aries. With the Sidereal Zodiac, which is found in other forms of astrology such as
Jyotish, the astrology of India, the equinoxes and solstices move slowly backward through the
signs of the Zodiac at a rate of one degree between 70.59 and 72.15 years.