Early Astronomers What is the purpose behind Astronomy
Early Astronomers
What is the purpose behind Astronomy? �Explore the unknown beyond our atmosphere �Track planets, satellites (moons), stars, comets �Keeping time = Calendar �Navigation �Agriculture �Religious beliefs
Claudius Ptolemy �Greek Astronomer �Expanded upon Aristoltes’s theories with mathematical calculations �Ptolematic theory �Earth Centered Solar System �Geocentric � Geo = Earth � Centric = middle, center
Geocentric Model �Geocentric model
Nocilaus Copernicus � 1543 A. D. Published Heliocentric Theory �Helio = Sun, Centric = Middle �Heliocentric model �Theory was not popular especially with religious organizations
Tycho Brahe �Favored the geocentric model �Brahe Geocentric Model �Sun and moon orbit Earth �All other planets orbit the Sun
Johannes Kepler �Worked as Brahe’s assistant �Formulated 3 laws of Planetary motion � 1 st = Orbits are an ellipse � 2 nd = Planets move faster closer to sun � 3 rd p²=a³ �Favored Heliocentric Model �Sun not exact center of orbits
Galileo Galilei �Used telescope to observe celestial bodies �Discovered Galilean Moons of Jupiter, sunspots, physical features on moon �Favored Heliocentric model �Used phases of Venus to support model
Isaac Newton �Explained the force that allows planets to orbit around the sun �That force is……. . �Gravity
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