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![]() edHelper.com Ancient Greece |
Hipparchus |
| edHelper's suggested reading level: | grades 9 to 11 | |
| Flesch-Kincaid grade level: | 9.76 |
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Hipparchus
By Vickie Chao |
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1 Suppose we could travel back in time to note the positions of all the stars relative to the Earth. We then compare our observations with the current positions of those stars. Right away, we would notice that the positions of the stars have actually shifted systematically. This strange phenomenon is caused by a cyclic wobbling in the orientation of the Earth's axis of rotation. The entire cycle takes about 26,000 years to complete.