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| | Could Earth be Revolving around the Sun? |
 | | He gave the first estimate of the distance of the Moon (section (8c)), and it was his careful observation of a lunar eclipse--pin-pointing the Sun's position on the opposite side of the sky--that enabled Hipparchus, 169 years later, to deduce the precession of the equinoxes). |
 | | However, one could guess why he believed that the Sun, not the Earth, was the central body around which the other one revolved. |
 | | Knowing the Sun's motion across the sky, Aristarchus could also locate the point P in the sky, on the Moon's orbit (near the ecliptic), which was exactly 90 degrees from the direction of the Sun as seen from Earth. |
| www-istp.gsfc.nasa.gov /stargaze/Sarist.htm (1068 words) |
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