P.O.G.I.L Theories of the Universe Ptolemy 100- 170 AD Geocentric model which puts earth in the middle of the universe. Ptolemy placed Earth at the center of the Universe and the Moon, Mercury, Venus, the Sun, Mars, Jupiter and Saturn circling around our planet. Evidence: Observation—We see the Sun go across the sky and it doesn’t feel as if the Earth is moving Copernicus 1507 Argued that Earth was only one of several bodies that orbit the Sun. The Earth itself is a small and unimportant compared to the rest of the Universe. Called it the Heliocentric Model of the Universe. (Sun is in the center) Evidence: observation and math Galileo 1564-1642 Improved the telescope and saw moons orbiting Jupiter Supported Copernican’s theory of the universe (Heliocentric model where the Sun is in the center of the solar system). Evidence: Observation with better telescopes and math models of the orbits. Big Bang Theory Proposed in 1927 There was a cosmic explosion that started the expansion of the universe. Occurred 14 billion years ago After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later simple atoms. Giant clouds of these primordial elements later coalesced through gravity in halos of dark matter, eventually forming the stars and galaxies visible today. Evidence: From redshift from galaxies, from cosmic background radiation, and the temperature prediction closely matches actual measurements. Cyclic Theory Proposed in 1930 and updated in 2001 The Big Bang was not the beginning but a bridge between one cycle of the universe to the next. The Universe undergoes endless cycles of evolution in infinite space and time Evidence: 1. The fact that if there was a Big Bang, what triggered it? 2. The idea that there is no end. 3. The role of dark matter (to start a new cycle of the Universe) 4. The observed cosmic acceleration (that empties the Universe so a new one can begin) 5. That Black Holes trigger the crunch part of the cycle. Inflation Theory Proposed in 1980 This is an important addition to the Big Bang Theory. Addresses the issue of how some regions of space are clumped together and others are not. If there was only an explosion then the particles should all be distributed evenly around the Universe. Evidence: Background radiation and WMAP data showing direction of the vibration of waves.

Theories of the Universe Start Time: End time: Explore: 1. What was Ptolemy's Theory of the Universe? 2. When was this theory popular? 3. What was the evidence for his theory? 4. What was Copernicus’ Theory of the Universe? 5. When did he propose this theory? 6. What was the evidence for his theory? Which theory did Galileo support? Why did Galileo support it? What was his evidence? Theories of the Universe Understand: Draw Ptolemy’s Theory 10. Draw Copernicus’ Theory 11. Which theory is closer to our current understanding of the position of the Sun and Earth? 12. Is this a Theory of the Universe or the Solar System? Explain why? Definition: 13. Define Solar System. 14. Define Universe Analyze: 15. Compare and Contrast Solar System and Universe. Team roles Team Member Scientist: read questions, keep track of time, make sure all participate Engineer: Talks to instructor, speaks for the team Mechanic: Get materials, records answers Technology: look up information on internet, share results found

Current Theories of the Universe Start Time: End time: Explore: What is the Big Bang Theory? How long ago did the universe begin? What are the steps to the Big Bang Theory? 4. What is the evidence for the Big Bang Theory? 5. What is the Cyclic Theory? 6. What is the evidence for it? 7. Why is the Inflation Theory an important addition to the Big Bang Theory? 8. What is the evidence for it? Understand: How do the Cyclic Theory and the Inflation Theory effect the Big Bang Theory? Definition: 10. Define Theory-- Analyze: 11. Why are these all theories and not laws (like Newton’s 3 laws)? 12. Will the current Theory of the Universe change in the future? Why or Why not? Current Theories of the Universe