The stars appear fixed in space from an earth-bound perspective, but the equinox and solstice points would appear to be moving in a retrograde direction at the rate of about one degree per 72 years. An analogy would be a gyroscope or toy top, that does not maintain an identical axis from year to year as it spins around.įrom a very long-term perspective on earth, this "wobble" means that if one wished to fix the spring equinox at a point when the sun is at zero degrees in the sign of Aries, as astrologer Claudius Ptolemy did over 1800 years ago over the centuries, the equinox point would appear to be slipping backward into the previous sign of Pisces, and headed on its way to Aquarius. On a time-frame of about 26,000 years, the earth's rotating axis seemingly describes a small circle or cone, which has been nicknamed a "wobble" in the earth's rotation. This axis shifts in space - very slowly, though, during millenia. The earth rotates on an axis, which can be visualised as a line through the North and South Poles, much like the center of a spinning top.
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