Astronomy 1021 Lecture Notes - Leap Year, February 29, Solar Time

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Document Summary

Path of the planets, timekeeping, some history astronomy . Goals : describe motions of the planets in earth"s sky, difference between motions of inner and outer, reproduce how the geometry of the solar system results in planetary motions. Dance of the planets : five planets visible: mercury, venus, mars, jupiter, saturn, these objects slowly wander through constellations of the zodiac. In ancient civilizations, their long-term motions with respect to the stars was highly puzzling . Mars, jupiter and saturn : outer planets sometimes move backwards and make a loop in the sky over periods of weeks or months. This is called retrograde motion: occurs when planet is at opposition when the planet is on the opposite side of the sky from the sun, planet is then visible entire night, see animation/starry night. Inner planets: inferior and superior conjunction: opposition: outer planet appears in opp. Sky to the sun. (missed slides, see power point)