astronomy 3

astronomy 3 - Sean O'Keefe Astronomy 106 Section 102...

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Sean O’Keefe Astronomy 106 Section 102 February 4, 2008 Homework #3 1.) Could not do. I have do not have a new book, and only the new books come with the information. 2.) Lunar Eclipses a. The Moons diameter is only 2,160 miles long, while the umbra of Earth’s shadow is 860,000 miles long. b. Lunar eclipses led Aristotle to conclude that Earth is a sphere because only a sphere can cast a shadow that was always circular. 3.) Motions of the Planets a. The orbits of Mars and Mercury appear to Earth to just poke above the horizon at sunset. The outer planets appear to be stars during the night. The outer planets also seem to move backwards then forwards for a short time. This is called retrograde. Though that is really just the Earth passing them on Earth’s faster orbit. b. c. The Copernican explanation (retrograde motion). Earth overtakes Mars; it appears to slow its eastward motion. As Earth surpasses Mars, it appears to move westward, or backwards. As Earth moves ahead of Mars, it
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astronomy 3 - Sean O'Keefe Astronomy 106 Section 102...

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