The Boulder Cosmology Group meets at 7PM on the first and third Thursdays of the month at the Main Boulder Public Library. Starting in September we will also meet on second Thursdays in the Boulder Creek Room to discuss selected readings.

See for a list of all materials covered in the Cosmology Group since it began meeting in 2003.

        Cosmology discussion group topics for 2012

On January 5 we will wrap up the Whittle Cosmology series with two lectures by Steven Devadoss on the topology and geometry of the universe.
On January 19, we will start a new Teaching Company lecture series. It consists of 24 DVD lectures numbered below in the schedule, viewed two per meeting, on “Particle Physics for Non Physicists” by CU Professor Steven Pollock. These lectures should be accessible to anyone with a very modest science background. We will also discuss optional supplemental reading, mostly from Robert Oerter’s book, The Theory of Almost Everything, which tracks the Pollock lectures fairly closely.

On September 20 we will start a new series of DVD lectures on the first and third Thursdays, “Dark Matter, Dark Energy: The Dark Side of the Universe” by CalTech Professor Sean Carroll.

We will watch each 30 minute lecture and then discuss it, and will attempt to cover two lectures in each meeting. We will meet in the Boulder Creek Meeting Room on the first floor of the main Boulder Public Library on the first and third Thursdays of each month at 7-9 PM, beginning January 5.

On September 13 we will begin discussing selected readings on the second Thursday of the month in the Boulder Creek Room.

Here's the expected schedule.   Dates may slip.


Two lectures from Satyan Devadoss’s DVD lecture series “The Shape of Nature”. These lectures, titled “The Topology of the Universe” and “The Geometry of the Universe”, will cover the qualitative and quantitative nature of the shape of the space that makes up our Universe.

1. 1/19/2012 Nature of Physics (The first Pollock lecture.)

What is the world made of, how do the constituents fit, and what are the fundamental rules they obey? We discuss the history of human understanding of atoms and subatoms, and articulate some primary ideas in particle physics, focusing on what we know well.

2. 1/19/2012 Standard Model of Particle Physics

Where do we stand in our understanding of the smallest building blocks of the world? The Standard Model of particle physics is one of the greatest quantitative success stories in science. What are the players, what are the forces, and what are some of the concepts and buzzwords?

3. 2/2/2012 Pre-History of Particle Physics

We summarize the scientific evolution of atomism: prescientific ideas, the classical worldview of Isaac Newton, and finally the modern ideas of fundamental constituents. How could a famous physicist say physics was “done” in 1899?

4. 2/2/2012 Birth of Modern Physics

We explore the transition from 19th-century classical physics to 20th-century modern physics. This is the story of Planck, Rutherford, Einstein, and the early quantum physicists. We gain our primitive first understandings of the realistic structure of atoms.

5. 2/16/2012 Quantum Mechanics Gets Serious

A qualitative introduction to the work of Schrödinger, Heisenberg, and Dirac in describing electrons, this lecture looks at how the first fundamental particle was discovered. We introduce such concepts as spin and quantum electrodynamics (QED), and conclude with the experimental discovery of antimatter and the neutron. Eight key stages are in between, including the condensation of atoms, the birth of the first stars, and the formation of galaxies.

6. 2/16/2012 New Particles and New Technologies

This lecture conducts a survey of particle physics in the first half of the 20th century: cosmic rays, the discovery of the muon (“Who ordered that?”), Yukawa’s theory of nuclear force, and the discovery of the pion. We conclude by discussing the electron volt (ev) as a tool to make sense of the particle discoveries to come.

7. 3/1/2012 Weak Interactions and the Neutrino

What is a weak interaction, and how is it connected to radioactivity? What is an interaction, anyway, and how does it differ from a force? We discuss the carriers of weak forces, W and Z particles, and introduce neutrinos (ghostlike particles with no mass).

8. 3/1/2012 Accelerators and Particle Explosion

Particle accelerators, born after World War II, were in some respects the origin of big science in the United States. We discuss how these machines worked and the steady stream of new particles discovered through their use.

9. 3/15/2012 Particle “Zoo”

Some new particles exhibited a curious mix of strong and weak properties. The proper description of these "strange particles" was crucial in understanding the particle “zoo.” This lecture introduces lots of new lingo (mesons and baryons, hadrons and leptons, bosons and fermions).

10. 3/15/2012 Fields and Forces

This lecture covers the concept of a field and the early problems involved in constructing the modern theory of quantum electrodynamics (QED). We examine the 1947 Shelter Island conference, the problem of infinities, the concept of renormalization, and Feynman diagrams.

Note! 4/5, 4/19, 5/3: No DVD viewing. We will meet in the Arapaho conference room near the top of the stairs to discuss Martinus Veltman's Facts and Mysteries in Elementary Particle Physics.

04/05/2012 Veltman, Chapters 1 to 4.

04/19/2012 Veltman, Sections 7.3 and 7.6, and Chapter 8.

05/03/2012 Veltman wrapup (Chapters 9 thru 11 and any remaining questions on the rest of the book), and a presentation, “Lie Groups in Physics”, from Paul and Chela on symmetry and the standard model.

11. 5/17/2012 “Three Quarks for Muster Mark”

Hadrons (strongly interacting particles) are fundamental but not elementary. Could they be made of something else? This is the breakthrough idea of quarks. This lecture explores early quark conditions.

12. 5/17/2012 From Quarks to QCD

If quarks are the fundamental particles, how do they interact? The answer: They carry a new charge, a strong charge described by color. We introduce these concepts as part of the fledgling theory of quantum chromodynamics (QCD) from the 1970s.

13. 6/7/2012 Symmetry & Conservation Laws

What does symmetry mean to a physicist? Pretty much what it means to you: an aesthetic property of a system, a pattern that appears the same when viewed from different perspectives.
      (Here are a couple of pages of notes from Bill on symmetry and particle physics.)

14. 6/7/2012 Broken Symmetry, Shattered Mirrors

Symmetry is sometimes slightly broken or badly broken. Either way, there is something useful to be learned about the world. This lecture explores (a seemingly obvious) mirror symmetry, also called parity, and the stunning surprise that it is not perfect (parity violation).

15. 6/21/2012 November Revolution of 1974

In November of 1974, two simultaneous experimental discoveries rocked the world of particle physics. A new particle, a new quark, had been found. The charmed quark changed the scientific paradigm for physicists overnight.

16. 6/21/2012 A New Generation

The last great surprises: a new generation of particles. The tau lepton is discovered, and symmetry arguments tell scientists that the tau neutrino, and bottom and top quarks, have to be there ... and they are!

Turned out to be an impromptu showing of Lecture 19, “The Higgs Particle” because of the July 4 announcement by CERN of the discovery at the LHC of the Higgs Boson.

17. 7/19/2012 Weak Forces and the Standard Model

Progress in the 1960s and 1970s was not limited to strong forces and quarks. This is the story of the theory of Weinberg, Salam, and Glashow (the electroweak theory) that unified the fundamental weak, electric, and magnetic forces. We can now summarize the Standard Model.

18. 7/19/2012 Greatest Success Story in Physics

The Standard Model of particle physics is an impressive accomplishment. Its unparalleled success includes qualitative and quantitative measurements, with years of increasingly precise tests.
Supplemental Reading: Oerter, Chapter 10 and Appendix C.

19. 8/2/2012 The Higgs Particle

The Higgs particle is the least understood piece of our story so far, and the one central part not yet directly verified. What is this particle, and what role does it play in the Standard Model?

Supplemental readings: Wilczek, “In Search of Symmetry Lost” and Strassler, “If the Higgs Field were Zero”.

20. 8/2/2012 Solar Neutrino Puzzle

We have always assumed that neutrinos are massless, but what if they did have mass? Why are there far fewer neutrinos coming from the sun than there should be? What does it mean to talk about neutrinos changing flavor?

21. 8/16/2012 Back to the Future (1) - Experiments to Come

The SSC may be dead, but experimental particle physics is alive and vibrant! What are some of the burning issues? Among those we will discuss are the search for violations of matter-antimatter symmetry, and neutrino beams that will travel through the Earth from source to target.

22. 8/16/2012 Back to the Future (2) - Puzzles and Progress

The Standard Model is a great success. So why are many physicists looking for a more fundamental theory of nature? We'll begin with the missing link of gravity; issues of simplicity, unification, and grand unification; then two developments that to many physicists seem to be the best candidates for new physics: supersymmetry and string theory.

23. 9/6/2012 Really Big Stuff - The Origin of the Universe

What does cosmology, the study of the universe as a whole, have to do with particle physics? Matter at the very largest scales requires understanding of matter at the very tiniest. We'll discuss how particle physics fits in with the Big Bang, the more recent theory of inflation, and the newly discovered dark matter and dark energy.

24. 9/6/2012 Looking Back and Looking Forward (The last Pollock lecture)

What have we learned after more than 100 years of intense study of fundamental particles? What puzzles remain? What you might take out of this course is a sense of physical order and understanding of the constituents of the larger world.
Here, is an update from Dave Peterson on developments in particle physics since the Pollock lectures.

9/13/2012 Book Discussion: Deep Down Things: The Breathtaking Beauty of Particle Physics, by Bruce Schumm. Chapters 1 to 5.

In September we will start a new Teaching Company lecture series. It consists of 24 DVD lectures numbered below in the schedule, viewed two per meeting, on “Dark Matter, Dark Energy: The Dark Side of the Universe” by CalTech Professor Sean Carroll.

1. 9/20/2012 Fundamental Building Blocks (The first Carroll lecture)

Scientists now have a complete inventory of the universe, which is composed of three basic constituents: Ordinary matter includes every kind of particle ever directly observed; dark matter consists of massive particles known only because of their gravitational effects; and dark energy is a smoothly distributed component that whose density does not change as the universe expands.

2. 9/20/2012 The Smooth, Expanding Universe

Imagine looking into a clear night sky with perfect vision. What would you see? This lecture surveys the visible universe - from the stars in our galaxy to the cloudy patches called nebulae that astronomer Edwin Hubble proved are galaxies in their own right - and Hubble's discovery that the universe is expanding.

3. 10/4/2012 Space, Time, and Gravity

Einstein taught us that space and time can be combined into spacetime, which has the ability to evolve and grow. Indeed, what we think of as gravity is just a manifestation of the curvature of spacetime. To find things in the universe—including dark matter and dark energy—all we have to do is to map out this curvature.

4. 10/4/2012 Cosmology in Einstein's Universe

The expansion of the universe is governed by its spatial curvature and energy density, both of which have specific ways of changing as the universe grows. These features are related to each other by Einstein's general theory of relativity, which can be used to model the past and possible future of the universe.

10/11/2012 Book Discussion: Deep Down Things, by Bruce Schumm. Chapters 6 and 7. Study guide from Jeff.

5. 10/18/2012 Galaxies and Clusters

Applying the laws of dynamics to galaxies and galaxy clusters, we find that more matter is required to account for their motions than can be observed. Some of the missing mass is hot gas; however, this is still not enough, and we need to invoke some new kind of particle in galaxies and clusters: dark matter.

6. 10/18/2012 Gravitational Lensing

Another way to detect invisible matter is to use light as a probe of the gravitational field. Passing through curved spacetime, the path of a light ray is deflected due to gravitational lensing. Lensing demonstrates the existence of gravitational fields where there is essentially no ordinary matter.

7. 11/1/2012 Atoms and Particles

We peer into the atom to discover the constituents of ordinary matter: nuclei and electrons. Nuclei are made of protons and neutrons, which in turn are made of quarks. Electrons and quarks are examples of fermions, or matter particles. There are also bosons, or force-carrying particles, such as photons and gluons.

8. 11/1/2012 The Standard Model of Particle Physics

In the 1960s and 1970s, physicists developed a comprehensive theory of known fermions and bosons. Now called the standard model, this theory fits an impressive amount of data, but it leaves two crucial puzzles: the hypothetical Higgs boson and the graviton, the carrier of the gravitational force.

11/8/2012 Book Discussion: Deep Down Things, by Bruce Schumm. Chapter 8. Study guide from Jeff. Notes from Paul's talk in May on Lie Groups in Physics.

9. 11/15/2012 Relic Particles from the Big Bang

Armed with the core principles of particle physics, we know enough about the early universe to predict how many of each type of particle should be left over from the Big Bang. These "relic abundances" are crucial to understanding the origin of dark matter and light elements.

10. 11/15/2012 Primordial Nucleosynthesis

The process of nucleosynthesis describes how protons and neutrons were assembled into light elements during the first few minutes after the Big Bang. We can observe these primordial elements today and check on Einsteinian cosmology and a stringent constraint on theories of dark matter.

11. 12/6/2012 The Cosmic Microwave Background

About 380,000 years after the Big Bang, the universe had cooled sufficiently for electrons and nuclei to combine into atoms allowing light to travel much more freely. The relic photons from this era are visible to us today as the cosmic microwave background, which holds clues to the composition and structure of the universe.

12. 12/6/2012 Dark Stars and Black Holes

Candidates for dark matter include small, dark stars called Massive Compact Halo Objects (MACHOs) and black holes. Such objects are ultimately composed of ordinary matter, of which there just isn't enough to account for the dark matter. We are forced to conclude that the dark matter is a new kind of particle.

12/13/2012 Book Discussion: Deep Down Things, by Bruce Schumm. Chapters 8 to 10. Study guide from Jeff. Notes from Paul's talk in May on Lie Groups in Physics.

13. 12/20/2012 WIMPs and Supersymmetry

Weakly interacting massive particles (WIMPs) are ideal candidates for what comprises dark matter. WIMPs may have their origins in supersymmetry, which posits a hidden symmetry between bosons and fermions, and predicts a host of new, as-yet-unobserved particles, including WIMPs.

14. 12/20/2012 The Accelerating Universe

In the late 1990s, two groups of astronomers found to their astonishment that the expansion of the universe is speeding up rather than slowing down. Such behavior can't be explained by any kind of matter and suggests the existence of an entirely new component: dark energy.


For more information, e-mail group leader Jeff Grove:

This is, last updated November 2, 2012.