1. Announcements
Reading assignment for next time: read The Degenerate Era, The Black Hole Era, The Dark Era and The Conclusion
1st Quarter Observing Night tonight: cloudy and cold so it will be inside. Set-up will start at 6:45pm. Meet in the 3rd floor B-wing hallway by the astronomy storage room.

2. Colored Card Question The current cosmological decade is The 1st
The 10th
The 13th
The 25th
None of the above

3. Another colored card question
The last stars will die out in which cosmological decade?
The 1st
The 14th
The 23rd
The 50th
I don’t have a clue.

4. The Primordial Era
-50 < h < 5

5. The four forces of nature in the Primordial Era

6. Cosmological Inflation
The “bang” of the Big Bang

7. Inflation solves the flatness problem

8. Inflation solves the Horizon Problem

9. An Analogy for the Expanding Universe
Where is the center of this universe? Is it “in” the universe?

10. Colored Card Questions
ClassAction website Cosmology module
Centerless Expansion Models
Effects of Expansion
Universe Changes

11. In-class Activity
Do “The Big Bang” lecture-tutorial. Work together in groups of two or three. You have 20 minutes.

12. Recombination
Recombination is a misnomer. The electrons and protons had never been together before this time

13. Stretching the CMB

14. Where did all the matter come from?
Electron-positron pair production and annihilation

15. Virtual particles and vacuum energy
There had to have been some small number of cases where a particle was created without an antiparticle. We still don’t understand how that can be.

16. What is the atomic content of the Universe?
The Big Bang theory predicts that the universe is made of hydrogen and helium with traces of deuterium, tritium, helium-3, lithium and beryllium