1. Announcements Exam 1 is next time. Will cover The Five Ages of the Universe. 15 to 18 multiple choice questions and 3 essays. I will probably give you a list of 5 to 7 essay questions to choose from. For next Monday, read the first two chapters of Foundations of Modern Cosmology

2. Colored Card Question During the black hole era the only “ordinary” matter left is a)free protons and neutrons b)electrons and positrons c)hydrogen and helium d)None of the above, there is no “ordinary” matter left during the black hole era

3. Another Colored Card Question The Dark Era begins around which cosmological decade? a)The 10 th b)The 101 st c)The 40 th d)The 80 th

4. One More Colored Card Question During the Dark Era, typical wavelengths of light are measured in a)kilometers b)meters c)lightyears d)huge multiples of the size of the currently visible universe

5. The Black Hole Era To understand black holes, we need to explore Einstein’s General Theory of Relativity

6. The Equivalence Principle

7. Consequence of Equivalence Principle: Light is affected by gravity

8. Space-time gets warped near any massive object

9. Near a black hole the warping of space-time is extreme

10. Visual distortions caused by a black hole

11. Time runs differently near a black hole

12. Tidal forces stretch and squeeze anything falling into a black hole The process is called Spaghettification. Watch spaghettification video

13. Schwarzschild Black Hole

14. Kerr Black Hole

15. Most black holes now are accreting mass and have jets Because the star that formed the black hole was rotating and the mass falling in spirals inward, the black hole is rotating: it is a Kerr black hole

16. The Binary Pulsar When they finally collide, they will form a black hole. Watch Binary Pulsar and Neutron Star Merger videos

17. Black holes won’t last forever

18. Hawking Radiation

19. At the end of the Black Hole Era only electrons, positrons, extremely long wavelength photons and a few exotic elementary particles remain. The Dark Era is truly dark

20. The Dark Era e+e+ e-e- e-e- e+e+

21. Phase Transitions Ice pockets forming in a salt water pool

22. Quantum Mechanical Tunneling

23. The Universe could tunnel to a new vacuum energy state

24. The probability of tunneling depends on the wave properties of the universe

25. The Heat Death of the Universe

26. An Alternate End: The Big Crunch

27. The more likely ending: The Big Rip