1. Cosmology How did our universe form?

2. The study of the universe – its nature, origin and its evolution

3. Big Bang Theory Theory that the universe began as a point and has been expanding ever since About 13.7 billion years ago EXPANSION rather than an explosion

4. Steady State Theory Universe looks the same on large scales to all observers Matter is added to created and added as universe expands Density remains the same

5. Possible Outcomes* Open Universe – Expansion will never stop Closed Universe – Expansion stops and turns into contraction Flat Universe – Expansion slows to a halt * Based on Big Bang Model

6. Background Noise Cosmic background radiation: –Weak radiation left over from the early hot stages of the Big Bang expansion of the universe Discovered in 1965 in a lab in Holmdel, New Jersey

7. Background Noise Continued… Average temperature of CBR is 2.735 K (-270°C) Earths atmosphere blocks most of the radiation. Best seen by satellites or high altitude balloons

8. COBE Cosmic Background Explorer –Orbiting observatory used to map radiation in detail (1989) WMAP: Wilkinson Microwave Anisotropy Probe (2001)

9. On your own… Questions 4-8