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Heliocentric model of the solar system. Reading: Unit 11 Copernicus Galileo. Ptolemy’s geocentric model. Endured for nearly 1400 years!. Ockham’s razor. All things being equal, the simplest solution tends to be the best one . Nicolaus Copernicus (1473-1543). Heliocentric model.
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Heliocentric model of the solar system Reading: Unit 11 Copernicus Galileo
Ptolemy’sgeocentric model Endured for nearly 1400 years!
Ockham’s razor • All things being equal, the simplest solution tends to be the best one
Heliocentric model • All orbits are circular • Sun is at the center • Stars do not move (with respect to each other)
Scientific method • Observe phenomenon • Hypothesize cause (how?) • Predict outcome • Test outcome Not established until 17th century!
Galileo did some really cool stuff • Built his own telescopes! • Found 4 moons around Jupiter • The Milky way was composed of stars • Found mountains on the moon • Observed sunspots • Saw phases of Venus
Phases of Venus The Ptolemaic and Copernican models make very different predictions about the phases of Venus. U. Tenn. Physics & Astronomy Dept.
Phases of Venus Galileo’s drawings of the phases of Venus
Starry Messenger
Sunspots, and the Moon • What do these have to do with the Copernican or Ptolemaic models? • Apparently nothing, but... • The philosophy that went with the Ptolemaic system expected the Sun, moon, planets and stars to be perfect. • Heavenly bodies were expected to be entirely different in character from Earth.
Sunspots, and the Moon António Cidadão Armagh Observatory
The “Galileo Affair” • Galileo the pope that the heliocentric model was correct • (He had to take it back) • Home arrest for many years
Tycho Brahe (1546-1601) Famous for his accurate observations of the motions of the planets.
Tycho’s model • Sun orbits Earth • Other planets orbit Sun
Summary • Copernican model • Galileo’s evidence • Tycho
Team Activity #14 Phases of Venus Draw sketches (top then bottom) on page 211 before answering question #1!!