1. ASTRONOMY AND THE BIRTH OF MODERN SCIENCE

2. ANCIENT ASTRONOMY Human Survival  Predict when to plant crops Indian ruins line up with Summer and winter solstice and spring /fall equinoxes  Read the stars to navigate ocean

3. OMENS 1054 AD Chinese see Supernova explosion (remnants are still detectable today)

4. GEOCENTRIC UNIVERSE – EARTH CENTERED Aristotle Greek philosopher’s (382-422 AD) Objects moved around the earth in a perfect circle Didn’t explain 1. varying planet brightness 2. Retrograde motion (apparent backwards motion )

5. HELIOCENTRIC MODEL (SUN-CENTERED UNIVERSE Nicholas Copernicus (1473-1543)  Earth spins on its axis and orbits the sun, only moon orbits earth  Explains daily light dark and seasonal changes as well as retrograde motion and planet brightness Johannes Kepler (1571-1630) and Tycho Brahe (1546-1601) Kepler used Brahe’s and Copernicus’s observations to create mathematical models that described the orbits of the planets and their distance from the sun.

6. MODERN ASTONOMY Galileo Galilei (1564-1642) 1. First to use telescope to see A. Sunspots that moved across the sun showing sun’s rotation B. Jupiter’s 4 main moons, showing moons revolved around something other than Earth C. Phases of Venus

7. MODERN ASTRONOMY Isaac Newton (1642-1727) Born the day Galileo died Laws of Motion described how and why planets moved the way they did 1. !st Law Inertia 2. 2 nd Law F= ma 3. 3 rd Law: For one force there is an equal and opposite force.

8. THE EXPANDING UNIVERSE Edwin Hubble (1889-1953) The Hubble Expansion Law In 1929, Edwin Hubble announced that almost all galaxies appeared to be moving away from us. This phenomenon was observed as a redshift of a galaxy's spectrum. This redshift appeared to have a larger displacement for faint, presumably further, galaxies. Hence, the farther a galaxy, the faster it is receding from Earth.