9.12.07 Astronomy notes

9.12.07 Astronomy notes - Ex: moon going around earth. (1...

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9/12/07 – Astronomy Kepler’s laws: Explained epicycles, offset deferent centers 1. Orbital paths are elliptical, NOT circular, with the sun at one focus 2. An imaginary line connecting the sun to any planet sweeps out equal areas of the ellipse in equal intervals of time 3. The square of a planet’s orbital period is proportional to the cube of its semi major axis - P 2 = constant * a 3 - p = a 3/2 ; a = p 2/3 example: Jupiter is 5.2 times as far from the sun than the earth. [semi major axis of Jupiter = 5.2 AU). p = 5.2 3/2 = 11.86 years = orbital period of Jupiter.
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Unformatted text preview: Ex: moon going around earth. (1 lunar month) 2 = earths constant * (1 EM distance) 3 (P / 1 lunar month) ^2 = (a / 1 EM distance) ^3 KIII gives relative size of solar system astronomical units (AU) 3 E 5 km/s = (2*.3 AU) / 300 s derived from Venus orbital period AU = 1.5 E 8 km absolute scale for solar system Newton: introduced the why. Theorist, whereas Galileo was experimenter. Kepler = empirical Newton = physical law, fundamental principles. Gravity!...
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This note was uploaded on 09/24/2009 for the course ASTR 101 taught by Professor Christiansen during the Fall '08 term at UNC.

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