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The Moon Orbits the Sun?!?!

Even the most casual observers note the changes in the phase of the Moon as it goes from crescent to half to full and back again with a "monthly" cycle. (See Glenn Simonelli's PUMAS submission "Modeling the motions of the Earth, Sun and Moon" [PUMAS Example 03_10_04_1].) Their observations, or what is "common knowledge", lead them to believe the Moon does loops around the Earth. But is this true? A comparison of the gravitational forces of the Sun and Earth on the Moon hints at the answer to this question and a simple demonstration refutes the loop-view.


Stephen J. Edberg

Date Accepted: 2005-10-21 Grade Group: High School (9-12) Benchmarks: M3.4.1 M3.4.5 S13.4.6 S14.4.1 S14.4.2 Keywords: gravitation force moon sun earth tides inverse square law Microsoft Word: 08_19_05_1.docx PDF Document: 08_19_05_1.pdf