Originally Posted by Dirty F

The Earth's rotation on its axis has caused the Earth's shape to diverge from a sphere, and has caused the Earth's equatorial regions to bulge out, in the same way that a skater's skirt spreads outward as she spins rapidly on the ice. Because the Earth's equator is tilted with respect to the orbital plane of the Earth around the Sun, the so-called Ecliptic plane, the Earth's equatorial bulge is also tilted with respect of the plane along which the Sun and Moon travel. The Moon and the Sun exert a gravitational "tug" on the Earth's equatorial bulge, trying to pull the Earth's equatorial region to be aligned with the Ecliptic plane. This tug, along with the rotational motion of the Earth on its axis, the revolution of the Earth around the Sun, and the revolution of the Moon about the Earth, cause the Earth to wobble about its axis of rotation, similar to the motion of a spinning top. This motion is called Precession. An extension of the Earth's axis out into space traces out a conical figure with a time cycle or period of 26,000 years. Figure 3 below shows a schematic of the Earth's precession. The Earth's precession implies that although Polaris is currently the star above our North pole, in about 13,000 years Vega will become our North star; only, after yet another 13,000 years, will our North pole will once again point towards Polaris.

= basically saying that your zodiac sign is NOT your zodiac sign. They all moved one over time because of the earth changing positions as explained above.