1. Views & Theories of the Universe

2. Ptolemy’s Theory Proposed around 127-145 AD
Earth was the center of the universe
The sun, moon, stars, and planets all orbited in a circle around the earth

3. Ptolemy’s Theory

4. Copernicus’ Theory Proposed in 1543
The Sun was the center of the universe
The earth and planets all orbited in a circle around the sun; The moon orbited around the earth
The stars did not move

5. Copernicus’ Theory

6. Kepler’s Theory Proposed in 1609
Planets move around the sun in an elliptical motion, not a circular motion
Planets speed up as they approach the sun and slow down as they move away

7. Kepler’s Theory

8. Big Bang Theory Proposed in 1927
Universe was smaller than a pinhead, then it exploded and expanded
As the universe cooled, hydrogen and helium atoms began to form
The universe is slowly expanding to this day

9. Big Bang Theory

10. Steady State Theory Developed in 1948
The universe has no beginning and no end
The universe is in perfect balance (when stars die, new ones are created – like when a faucet is running and fills up a sink and the sink stays full)

11. Steady State Theory

12. Inflation Theory Proposed around 1980
The universe rapidly (and exponentially) expanded in its first few moments.
Extension of the Big Bang theory

13. Inflation Theory