earth aristotle bc 384-322 aristotle geocentric model
Post on 21-Dec-2015
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Earth
Aristotle BC 384-322
Aristotle
Geocentric model
Nicolas Copernicus1473-1543
Eyeball observations
De Revolutionibus
The Earth rotates on its axis once daily and revolves around the Sun once yearly.
Heliocentric Model
Tycho Brahe (1546-1601)
Johann Kepler (1571-1630)
Kepler’s 1st Law “ellipses”
Kepler’s 2nd Law “equal areas in equal times”
Planet Period Distance P/D P/D2 P2/D3
Mercury 0.24 0.39 0.62 1.60 0.99
Venus 0.62 0.72 0.85 1.18 1.00
Earth 1.00 1.00 1.00 1.00 1.00
Mars 1.88 1.52 1.23 0.81 1.00
Jupiter 11.9 5.20 2.28 0.44 1.00
Saturn 29.5 9.51 3.10 0.33 1.01
Kepler’s 3rd Law“Harmonic Law”
Astronomical Unit
Average Distance to Sun from the Earth
1 A.U. = 150 million km
Examples:Mercury 0.4 A.U.Neptune 30 A.U.
