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| | ipedia.com: Cycles Article (Site not responding. Last check: 2007-11-07) |
 | | Cycles may be due to restorative forces causing repetition as in simple harmonic motion, regularity of motion such as daily, monthly, yearly, and other astronomical cycles, or being affected by something else that has these qualities. |
 | | Pythagoras' study of music and Ptolemy's motion of the planets were early scientific studies of cycles. |
 | | Our understanding of weather cycles being attributable to annual and monthly astronomical motions was extended by Milutin Milankovitch who showed that ice ages were closely related to variations in the Earth's orbital eccentricity, axial tilt and the precession of the equinoxes which have periods of around 100,000 years, 40,000 years and 26,000 years respectively. |
| www.ipedia.com /cycles.html (794 words) |
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