Cosmology GES339 Spring 2008
Syllabus
 
Texts:    1. Wrinkles In Time Smoot 2005
              2. The First Three Minutes Weinberg 1993 (Bookstore notes Printed 2007, same book)
            3. Ned Wright's Cosmology Tutorial http://www.astro.ucla.edu/~wright/cosmolog.htm
            4. Calibrating the Cosmos: How Cosmology Explains Our Big Bang Universe (With Amazon online reading upgrade) Levin 2007 (Set up an Amazon account and buy the upgrade with the book)
                
II. Evaluation basis: Three exams (non-comprehensive), 5-7 homework assignments, and
                   Project:   a. Research paper, 10-15 pages, approved topic, properly cited.
                   and      b1. Individual PowerPoint presentation, derived from the paper, defined audience, 20 min, presented to class & to Celebration of Student Creativity & Learning.
                   Or        b2. Poster presentation by 1-3 students, approved topic, defined audience, presented to class and to the annual Celebration of Student Creativity and Learning.
The course average will include 6 grades: 3 exams, 1 project, 1 assignments, + best of these.
Optional credit: You may add an incremental letter grade to your course grade (e.g. B+ to A-) by arranging for and presenting a PowerPoint presentation or poster to a school class in the community. You may borrow another studentÕs presentation or poster for this.
 
III. Topical Outline:
1.   What is Cosmology? Readings: Smoot Ch. 1-2, 4 & Levin Ch. 1
    a.   Tues1/22 Definition of Universe has changed often, but each definition meant "everything".
    b.   What is the universe made of?
    c.   Why is the sky black?
    d.   How big is it, or is it infinite?
    e.   How old is it? Can it be infinitely old? (Steady State discussed in Smoot Ch. 4)

    Thurs 1/24 Age: 19th Century estimates of the age of the earth
    a.   Darwin
    b.   Salinity of sea
    c.   Cooling time—thermal outflow through the crust
    d.   Solar energy from gravity—Kelvin timescale
   
2.   Tues 1/29 Expanding universe Readings: Smoot Ch. 3 Levin Ch. 2,3,5
    a. Is the universe evolving with time? If so, what was its past, what is its destiny?
    b. Is it changing in a constant manner, or is the change itself variable?
    c. What can we know about its origin?
    d. Can we ask its temperature? Is this changing?Hubble law, Hubble radius, Hubble time
    e. Velocity, Doppler shift, cosmic red shift
    f. Red shift z defined
    g. Expansion and temperature
 
3. Thurs 1/31 Distance measurement Levin Ch. 2
a.   Parallax--Hipparcos satellite
b.   Discovery of universe of galaxies (Hubble; Cepheids)
c.   Photometric distance measurement (Reviewed next week, see below)
d.   Cepheid distance determinations
e.   Beyond Cepheid scale:
    1. Expanding photospheres—Type II supernovae
    2.   Type Ia Supernovae
f. Results: Expansion is accelerating.
 
Tues. Feb 5 Distance: In-class exercise: Subtracting proper motion from apparent motion to get parallax;
Relationship of parallax to distance
Inverse correlation of proper motion and distance: Choosing candidates for parallax studies.
The direction of motion of the Hyades cluster: The convergence point
The components of motion for a star whose direction (convergence point) is known.
Ratio of tangential and radial velocity from a component triangle
Distance is known when the tangential velocity and proper motion are known.
Distance is beyond easy parallax studies. We know with confidence the distance of this cluster.
 
Thurs. Feb 7 Distance: Standard Candles and photometric distance measurements.:  
An HR diagram (color-magnitude) reviewed.
The main sequence
The main sequence in the color-magnitude diagrams of different clusters
The different magnitudes of similar stars in different clusters are due to differences in distance.
Is reddening a problem?
Cepheid variable in M100

Tues. Feb 12 Guest lecture by Tom Burbine: What is a Planet? Lecture was part of Earth Science Search for Self.

Thursday Feb. 14: Very Luminous Standard Candles Also see Feb 7 Photometric Distances
a. Type II Supernovas
b. (Expanding photospheres (review)
c. Type Ia Supernovas
d. Modern approach to Type Ia as standard candles
e. Distance vs. redshift at high z
f. Accelerating Universe!

Tues Feb. 19 Holiday

Thurs. Feb. 21 Announcement of Exam 1 Next Thurs Feb 28  Material from beginning to Feb 14.

4. Newton, Einstein and gravity
a.   Equivalence principle
b.   Gravity and curved space—general relativity
c.   Mass curves space-time. Matter & radiation follow shortest curves—geodesics
d.   Curved space concept:
    1.   Euclid's 5th axiom
    2.   Extending geometry by violating the axiom:
    3.   Positive and negative curvature
    4.   Triangles
e. Some effects of the equivalence principle and curvature of space:
    1. Aberration of starlight by the sun
    2. Excess precession of the perihelion of Mercury
  
Tues. Feb 26
     3. Gravitational red shift in white dwarfs
     4. Einstein rings
          a. Einstein Cross
          b. Collection of gravitational Lenses
          c. Abell 2218: A galaxy cluster lens

Thurs Feb 28 Exam 1 Open notes (NOT printed or photocopied!)
Two questions-Time & Distance

Tues March 4
5.   Einstein universe model:
    a.   Gravity forbids static universe:
    b.   Einstein introduces cosmological constant: Lambda, to allow a static universe
    c.   Lambda represents some sort of universal energy field, unknown to science
    d.   Static universe so obtained is not stable; also, universe is expanding.
    e.   Einstein called Lambda his biggest blunder.
 
6. Thurs Mar 6 Friedmann universe models
    a.   Not static—Closed, open or critical, depending on density
    b.   There is a theoretical critical density.
        1. Critical density depends on measureable physical constants.
        2.   Critical density = 3*Ho2/[8*pi*G] In our universe it is 1.9 x 10-32 kg/m3
        3.   The ratio (actual universal density)/(critical density) = Omega.
    c.   Closed Friedmann universe: Expanding (or contracting) but bound:
        1.   Density greater than critical density (Omega > 1)
        2.   Would eventually start to contract if expanding
        3.   Closed—has a finite (increasing) volume
        4.   Positive curvature—all world-lines intersect twice
        5.   The above means this model has a beginning and an end.
    d.   Open Friedmann universe: Expanding and unbound:
        1.   Density less than critical density (Omega < 1)
        2.   Expands eternally at a decreasing rate, always above a limiting rate.
        3.   Open—has infinite volume
        4.   Negative curvature—world-lines diverge from an intersection
        5.   Has a beginning but no end
    e.   Critical Friedmann universe: Expanding and unbound:
        1.   Density equal to critical density (Omega = 1)
        2.   Expands eternally at a decreasing rate, limiting rate is zero
        3.   Open—has infinite volume
        4.   Zero curvature—familiar Euclidean geometry
        5.   Has a beginning but no end.
    f. The actual density is a topic in itself.
 
7. Tues Mar 11 Mass density in the universe (Announce Exam 2-From Feb 21 to Mar 13)
      (Exam 2 Topics: Gravity, Einstein & Friedmann universe models, Density of Universe,
        Age of Universe)
    a.   Luminous mass
    b.   Dynamical mass--includes dark matter in galaxies & clusters. Measured by gravity.
    c.   Baryonic mass—includes all ordinary matter made in the big bang. H/D ratio.
    d.   Theoretical total—includes enough matter to make space-time "flat". (Omega = 1. Reason comes later)
    e.   Amazing ratios of ordinary matter, dark matter, and energy, as we understand them.
 
8. Thurs Mar 13 Age of the Universe (Observational-compare with free-expansion time)
    a.   Age of the oldest star clusters (HR-diagrams & stellar evolution)
    b.   Age of the oldest white dwarf stars
    c.   Age of the radioactive elements
 
9. Tues Mar 18 The hot big bang and element formation: Gamow, Alpher, & Herman
    a.    Yelm
    b.   He production
    c.   Prediction of universal temperature
    d.   Penzias & Wilson
    e.   Cosmic background radiation
    f.   COBE spectrum
  
Thurs Mar 20 Exam 2

Tues Mar 25-Thurs Mar 27 Spring Break

10. Tues April 1 The first three minutes: Modern version
    a.   Elementary particles- photons, protons, neutrons, electrons, neutrinos & antiparticles in number equilibrium
    b.   As the temperature drops, the energy to make the heavier particles is no longer available, so annihilations become permanent and heavier particles become rare.
    d.   Finally, everything is rare except photons. That's the beginning of the modern universe; photons are a billion times more common than particles of matter.
    e.   Ultimately, temperature drops to where D is stable. Then all neutrons  (and an equal number of protons) become bound into He. The H-He ratio of the universe is set.
    f.   Density of matter

11. Thurs April 3 The radiation horizon: T = 340,000 years
    a.  Universe becomes transparent
    b.  Ripples in the matter density are present and potentially visible.
    c.  Appearance of the horizon strongly constrains age, total density, and structures.
    d. COBE results: First picture of the horizon.
    e.  WMAP results: The baby picture of the universe.
 
12. Tues April 8 Cosmic inflation:
    a.   Horizon problem
    b.   Flatness problem
    c.   Smoothness problem
    d.   Inflation concept: The return of Lambda with a physical basis. Omega = 1

13. Thurs April 10 Measurement of structure: