> "Precession that movement which causes the constellations to move backward across the heavens as each year passes.
Well, not really. Precession in more general terms is the physical phenomenon that can be demonstrated by a spinning top, which wobbles in a circular motion.
pre·ces·sion
n.
1. The act or state of preceding; precedence.
2. Physics The motion of the axis of a spinning body, such as the wobble of a spinning top, when there is an external force acting on the axis.
3. Astronomy
a. Precession of the equinoxes.
b. A slow gyration of the earth's axis around the pole of the ecliptic, caused mainly by the gravitational pull of the sun, moon, and other planets on the earth's equatorial bulge.
http://en.wikipedia.org/wiki/Precession_%28astronomy%29"Currently, this annual motion is about 50.3 seconds of arc per year or 1 degree every 71.6 years. The process is slow, but cumulative. A complete precession cycle covers a period of approximately 25,765 years, the so called Platonic year, during which time the equinox regresses a full 360° through all twelve constellations of the zodiac."
So yes, it can cause changes in the timing of the seasons, although our civilization from beginning to today covers less than 25% of the full cycle. Regardless, it is still noticeable; the Roman holiday Saturnalia is on the 25th of December and not on the day that the solstice occurs today. That holiday occurred on the solstice, if I'm not mistaken
