Cosmology

1. Cosmology Structure of the Universe

2. Open/Flat Universe Expansion continues forever Galaxies separate 100 trillion yrs. star formation ceased Temperature decreases Low-mass stars burned out Dead stars and black holes Matter, radiation, and black holes will diffuse and dissipate Empty space

3. Closed Universe Reaches maximum expansion Begins to collapse…everywhere at once Galaxies and materials will merge Temperature will increase Black holes merge into super massive black holes Atomic nuclei disintegrate Finally, space, time, and matter will collapse into a singularity The “Big Crunch”

4. Oscillating Universe Theorized by Richard Tolman Final stages of a closed universe will mimic the initial stages of the Big Bang Universe will rebound and expand The “Big Bounce” Not the to be confused with the Cyclic Model, in which only an extra dimension expands and contracts via the usual three dimensions

5. Critical Density Universe continued expansion dependent upon its critical density If the CD is > 1, or critical value , gravity will halt expansion If the CD is < 1, it will expand forever Dark Energy, Dark Matter and visual matter are the components factored into the equation

6. Steady State Theory Devised by Fred Hoyle, et al in 1948 A alternative to the Big Bang Theory Appearance of the universe does not change with time Universe has no beginning or end Galaxies receding from each other and are replaced by new ones form matter that is continuously created between them Big Bag observations and CMB radiation undermined this theory

7. Big Bang Theory Universe began 13.7 billion yrs ago Began with an infinitesimally small, hot, and infinitely dense singularity It inflated, expanded and cooled to the size it is today. Continues to cool and expand

8. Big Bang Theory There was no explosion, there was an expansion Space and time had an infinite beginning which corresponded to the origin of matter and energy The singularity did not appear in space, rather space began in the singularity Prior to the singularity, nothing existed, not space, time, matter or energy

9. Aleksandr Friedmann Formulated an early Big Bang Theory Classic paper “On the curvature of Space”, in 1922 Attempted to apply Einstien’s relativity to cosmology Universe is not static Three models: open, flat or closed Open/Flat have big bang singularity and expand forever Closed or “periodic world” of expand and contract dependent upon mass density

10. Georges Lemaitre Proposed an evolving cosmological model in 1927 Reluctant to accept a “beginning” Universe existed for an infinite amount of time in a nearly static state…a pure quantum state called a “primeval atom” The static state was unstable The universe expanded

11. Big Bang Evidence • 1. We are reasonably sure the universe had a beginning; • 2. Galaxies are moving away from us at speeds proportional to their distances (Hubble’s Law); • 3. There is a cosmological constant, a vacuum energy (Dark) accelerating the expansion; • 4. 74 % of the density of the universe is Dark Energy;

12. Big Bang Evidence • 5. Cosmic Microwave Background radiation (CMB), pervading the observable universe is the remnant of the early heat of the Big Bang; * • 6. The temperature of the CMB is just right for a flat/open universe; • 7. The abundance of hydrogen and helium in the universe were synthesized during the hot dense phase of the early universe;

13. George Gamow A primordial matter, a nucleus, exploded and broke down into its constituent particles Early nuclear reactions create light elements hydrogen and helium…currently hydrogen and helium account for 75% and 24% of a the observable matter in the universe Universe cooled and heavier elements were created Intense radiation for the Big Bang would continue to pervade the universe…CMB confirmed by Penzias and Wilson

14. Big Bang Evidence • 5. Cosmic Microwave Background radiation (CMB), pervading the observable universe is the remnant of the early heat of the Big Bang; * • 6. The temperature of the CMB is just right for a flat/open universe; * • 7. The abundance of hydrogen and helium in the universe were synthesized during the hot dense phase of the early universe; *

15. Big Bang Evidence • 8. Of the matter components of the universe, visible matter accounts for only 4% and Dark Matter accounts for 22%; • 9. Those amounts compared with the vacuum energy, Dark Energy, of 74%, gives a sum density ratio of < 1, indicating a flat/open universe. • 10. The Big Bang…open and expanding.

16. The Big Bang

17. Big Bang Timeline 0 Seconds/Time Zero Singularity: A state of extremely high density, pressure, and temperature. Planck Epoch 0 - 10-43 Earliest period of time…perhaps the shortest Gravity and fundamental forces may be unified Unstable, evolving, symmetry breaking Gravity separates from the other forces at the epoch’s end

18. Big Bang Timeline Grand Unified Theory Epoch 10 -43 End of Planck Epoch to 10 -43 Strong, weak, and electromagnetic forces united as the electronuclear force Forces separated at the end 10 -35 Triggered inflationary epoch The balance of matter/anti matter tips towards matter

19. Big Bang Timeline Inflationary Epoch 10-35 Universe swells to an object measured in inches Electro-Weak Era dominated by quarks and anti-quarks Particles and antiparticles annihilate into radiation and a tiny proportion of matter Inflation stops at 10-33 Hadron and Lepton Era 10 -10 to 10-6 Quarks confined in the formation of protons, neutrons, mesons, and baryons

20. Big Bang Timeline 1 Second+ No composite nuclei and neutrons decay to protons Protons 76% and neutrons 24% 3 Minutes+ Protons and neutrons combine to form hydrogen, deuterium, helium, and lithium nuclei

21. Big Bang Timeline 300,000 Years Matter and energy decouple from a state of thermal equilibrium Electrons and protons combine to form the first atoms Free electrons are removed in atom formation and the opaque universe becomes transparent allowing photons to travel long distances without being absorbed

22. Big Bang Timeline 1 Million Years Gas clouds form and proto stars begin to coalesce together 1000 Million Years Clusters of matter form quasars, stars, and proto-galaxies Stars begin to synthesize heavier elements 14.7 Billion Years New galaxies form with solar systems condensing around stars Atoms link to form complex molecules of life-forms Present observable universe

23. Big Bang Problems Singularity: Laws of physics can not apply to conditions of the event Inflation velocities above speed of light requiring an infinite time an infinite number of ergs (units of energy/work) Smoothness: Universe is clumpy Uneven distribution of galaxies and galaxy clusters Age of the Universe: Super clusters would take more than 14 billion years to form Would take nearly 100 billion years to attract matter at observed distances.

24. Big Bang Problems Cosmic Microwave Background Radiation: Fluctuations in the CMB indicates 100 times more dark matter than visible matter No observable evidence that dark matter exists It’s a theory to make Big Bang work

25. Plasma Cosmology Hannes Alfven Father of Plasma Physics Galaxies contain magnetic fields with charged particles orbiting within them Plasma contains electrical currents creating the magnetic fields Plasma universe is controlled by electricity and magnetism, not just gravity Electromagnetism accounts for the clumpiness of the universe and the fluctuations in the CMB radiation

26. Plasma • Regarded as the fourth state of matter • Its atoms contain free floating negative electrons and positively charged ions • Electrically conductive and responds to electro-magnetic fields • The solar corona and solar wind are plasmas consisting of electrons and protons

27. Future Class Sessions • String Theory • Multi-Universes • M-Theory • Branes • Parallel Universes • Null Cosmology