In 2016 the Boulder Cosmology Group met at 6PM for DVD lectures on the second and fourth Wednesdays of the month and reading discussions on third Mondays at the Main Branch of the Boulder Public Library.
See http://www.sackett.net/cosmologyAll.htm for a list of all materials covered in the Cosmology Group since it began meeting in 2003.
2016 Second and Fourth Wednesdays, selected DVD lectures from Professor Mark Whittle's course “Cosmology: The History and Nature of Our Universe”. This series of 36 half hour lectures covers the physics of the origin and evolution of the universe from the big bang to the present and beyond. Topics include how the universe started in the big bang, the cosmic microwave background and what can be learned from it, the expansion of the universe, which has been found to be accelerating rather than slowing as previously thought, the ‘cosmological principle’ that the universe is presumed to be roughly the same everywhere on very large scales, the composition of the universe which is only about 4% known, the formation of galaxies, stars, and the chemical elements, and the perhaps surprising outcome of all this that some parts of the universe are inhabitable. For a full description of the series, with descriptions of each lecture, visit http://www.teach12.com/tgc/courses/course_detail.aspx?cid=1830.
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 6-8 PM, beginning January 13. These lectures will start out slowly and move into more advanced topics, but will stay within reach of anyone with a modest background in science.
Expected Schedule with Monday book discussions flagged in bold:
January 11, 2016 Book Discussion: An Introduction to Modern Cosmology, by Andrew Liddle. Chapters 8 - 10.
Links to notes, derivations, and problem solutions from Boulder Cosmology Group Liddle discussions.
Note: This ^^^^ discussion was held a week earlier than usual because of Martin Luther King Day
January 13, 2016
1. The Journey Ahead
Cosmology takes the entire universe as its subject, not just its form, structure, and contents, but also how it was born and how it has evolved. You look at the origin of cosmology in creation stories before taking a whirlwind tour of the whole course.
2. Denizens of the Universe
This lecture introduces the hierarchy of structures in the universe: from planets to stars, galaxies, galaxy clusters, and larger groupings of galaxies called the cosmic web. Since light travels at a finite speed, looking far away also means looking far back in time.
January 27, 2016
3. Overall Cosmic Properties
The universe is lumpy at the scale of galaxies and galaxy clusters. But at larger scales it seems to be smooth and similar in all directions. This property of homogeneity and isotropy is called the cosmological principle.
4. The Stuff of the Universe
The most familiar constituents of the universe are atomic matter and light. Neutrinos make up another component. But by far the bulk of the universe is dark energy and dark matter. The relative amounts of these constituents have changed as the universe has expanded.
February 8, 2016 Book Discussion: An Introduction to Modern Cosmology, by Andrew Liddle. Chapters 11 - 13 & Advanced Topic 3.
Links to notes, derivations, and problem solutions from Boulder Cosmology Group Liddle discussions.
Note: This ^^^^ discussion was held a week earlier than usual because of Presidents' Day
February 10, 2016
5. The Sweep of Cosmic History
Take a quick trip through the history of the universe, from the big bang to a conjectured future of ever-accelerating expansion. Eight key stages are in between, including the condensation of atoms, the birth of the first stars, and the formation of galaxies.
6. Measuring Distances
Astronomers use a ‘distance ladder’ of overlapping techniques to determine distances in the universe. Triangulation works for nearby stars. For progressively farther objects, observers use pulsating stars, the rotation of galaxies, and a special class of supernova explosions.
February 24, 2016
7. Expansion and Age
Measurements of the Doppler shift of galaxies in the early 20th century revealed that essentially all were moving away from us. The more distant ones are moving faster, in direct proportion to their distance. This is the famous Hubble Law, which implies an initial ‘big bang.’
8. Distances, Appearances, and Horizons
Defining distances in cosmology is tricky, since an object's distance continually increases with cosmic expansion. There are three important distances to consider: the emission distance, when the light set out; the current distance, when the light arrives; and the distance the light has traveled.
March 9, 2016
9. Dark Matter and Dark Energy - 96%!
Atomic matter comprises less than 5% of the total cosmic census. This realization came with the discovery of dark matter (23%) in the 1970s and dark energy (73%) in the late 1990s. They are ‘dark’ because they are detectable only by their subtle gravitational effects.
10. Cosmic Geometry - Triangles in the Sky
Einstein's theory of gravity suggests that space could be positively or negatively curved, so that giant billion-light-year triangles might have angles that don't add up to 180 degrees. This lecture discusses the success at measuring the curvature of the universe in 1998.
March 21, 2016 Book Discussion: An Introduction to Modern Cosmology, by Andrew Liddle. Chapter 14 - 15 & Advanced Topics 4 - 6.
Links to notes, derivations, and problem solutions from Boulder Cosmology Group Liddle discussions.
March 23, 2016
Note: No meeting this day because of a snowstorm that closed the library.
April 13, 2016
11. Cosmic Expansion Keeping Track of Energy
Has the universe's rate of expansion always been the same? You answer this question by applying Newton's law of gravity to an expanding sphere of matter, finding that the expansion was faster in the past and slows down over time.
12. Cosmic Acceleration Falling Outward
You investigate why the three great eras of cosmic history radiation, matter, and dark energy have three characteristic kinds of expansion. These are rapid deceleration, modest deceleration, and exponential acceleration. The last is propelled by dark energy, which makes the universe fall outward.
April 18, 2016 Book Discussion: The Science of Interstellar, by Kip Thorne. Parts I - IV (Chapters 1 to 16).
April 27, 2016
13. The Cosmic Microwave Background
By looking sufficiently far away, and hence back in time, we can witness the ‘flash’ from the big bang itself. This arrives from all directions as a feeble glow of microwave radiation called the cosmic microwave background (CMB), discovered by chance in 1964.
14. Conditions during the First Million Years
You visit the million-year-old universe to take in the sights: a slowly changing rainbow sky, a low-density super-hot atmosphere, and everywhere, brilliant light.
May 11, 2016
15. Primordial Sound - Big Bang Acoustics
Earth's atmosphere is the medium for sound waves. Was the primordial atmosphere of the young universe also conducive to sound? The answer is yes, as proved by tiny variations in the CMB. You hear re-creations of this primordial sound, which is somewhere between a musical note and noise.
16. Using Sound as Cosmic Diagnostic
Slight differences in the properties of the universe lead to slightly different sound spectra. These differences allow cosmologists to use sound spectra to determine what kind of universe we inhabit. You listen to the primordial sound of three universes of different densities.
May 16, 2016 Book Discussion: The Science of Interstellar, by Kip Thorne. Parts V - VII (Chapters 17 to 31).
May 25, 2016
17. Primordial Roughness - Seeding Structure
There are two key players in the growth of structure in the universe: atomic matter and dark matter. This lecture looks at how dark matter created the framework into which atomic matter ultimately gathered. From these concentrations of atomic matter, stars and galaxies eventually formed.
18. The Dark Age - From Sound to the First Stars
How does the universe move from a smooth, uniformly filled state, ringing with primordial sound, to one with stars and galaxies? You follow the process that resulted in the first stars, which were massive, brilliant beacons lighting up the early universe.
June 8, 2016
19. Infant Galaxies
Once the first generation of stars had formed, they began to collect into infant galaxies, chaotic collections of stars and gas that were much smaller than today's huge, majestic galaxies. The best telescopic images, such as the Hubble Ultra Deep Field, show this exuberant period.
20. From Child to Maturity - Galaxy Evolution
The young universe matured into its present adult phase through the ceaseless collision of small galaxies to make big ones. Our own Milky Way galaxy formed this way and has a major collision looming in its future, 3 or 4 billion years from now.
June 20, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapters 1 - 2. Gravitation; Entropy, Statistical Physics, and Information.
June 22, 2016
21. Giant Black Holes - Construction and Carnage
At the heart of essentially every galaxy lies a giant black hole, a million to a billion times as massive as the sun. These monsters play an important role in the lives of galaxies. Confirming their existence was an impressive achievement of the Hubble Space Telescope.
22. The Galaxy Web - A Relic of Primordial Sound
A simulated intergalactic trip shows you the three-dimensional distribution of galaxies in our region of the universe. On the largest scale, galaxies form a weblike pattern that matches the peaks and troughs of the primordial sound in the early universe.
July 13, 2016
23. Atom Factories - Stellar Interiors
Humans are no less a part of the universe than any star or galaxy, and the atoms in us can only have arrived via a cosmological route. This lecture discusses how heavier elements came from stellar processes, including nuclear reactions and supernova explosions.
24. Understanding Element Abundances
The theory of atom genesis in the interiors of stars is confirmed by the proportions of each element throughout the cosmos. The relative abundances hardly vary from place to place, so that gold isn't rare just on earth, it's rare everywhere.
July 18, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapter 3. Electromagnetism and Maxwell's Equations.
July 27, 2016
25. Light Elements - Made in the Big Bang
There is one glaring error in the story of atom-genesis inside stars: far too much helium. It must have been produced in the big bang along with other light elements. According to theory, this occurred when the universe was just three minutes old.
26. Putting It Together - The Concordance Model
This lecture reviews the six key pieces of evidence that indicate that we live in an expanding, evolving universe that began in a hot big bang a few billion years ago. Together with five key observational datasets, these pieces yield a remarkably consistent picture called the concordance model.
August 10, 2016
27. Physics at Ultrahigh Temperatures
This lecture begins your investigation of the universe during its first second, which is an immense tract of time in nature. To understand what happened, you need to know how nature behaves at ultrahigh energy and density. Fortunately, the physics is much simpler than you might think.
28. Back to a Microsecond - The Particle Cascade
At one microsecond, all the particles of the standard model of particle physics were present. By the time the universe was a few minutes old, matter-antimatter annihilation and nuclear fusion had roughly created today's composition of mainly photons and a few protons, helium nuclei, and electrons.
August 15, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapters 4 - 5. Electromagnetic Waves; Special Relativity.
August 24, 2011
29. Back to the GUT - Matter and Forces Emerge
You venture into the bizarre world of the opening nanosecond. There are two primary themes: the birth of matter and the birth of forces. Near one nanosecond, the universe was filled with a dense broth of the most elementary particles. As temperatures dropped, particles began to form.
30. Puzzling Problems Remain
Although the standard big bang theory was amazingly successful, it couldn't explain several fundamental properties of the universe: Its geometry is Euclidean, it's smooth on the largest scales, and it was born slightly lumpy on smaller scales. The theory of cosmic inflation offers a comprehensive solution.
September 14, 2016
31. Inflation Provides the Solution
This lecture shows how the early universe might enter a brief phase of exponentially accelerating expansion, or inflation, providing a mechanism to launch the standard hot big bang universe. This picture also solves the flatness, horizon, and monopole problems that plagued the standard big-bang theory.
32. The Quantum Origin of All Structure
Inflation also helps explain the origin of cosmic lumpiness. During inflation, tiny quantum mechanical fluctuations can get frozen as real fluctuations when they expand faster than light, away from their place of origin. The expansion then stretches these fluctuations to cosmic proportions.
September 19, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapters 4 - 5. Electromagnetic Waves; Special Relativity.
Yes, we're still working on the same chapters as the August 15th discussion.
September 28, 2016
33. Inflation's Stunning Creativity
All the matter and energy in stars and galaxies is exactly balanced by all the negative energy stored in the gravitational fields between the galaxies. Inflation is the mechanism that takes nothing and makes a universe - not just our universe, but potentially many.
October 12, 2016
34. Fine Tuning and Anthropic Arguments
Why does the universe have the properties it does and not some different set of laws? One approach is to see the laws as inevitable if life ever evolves to ask such questions. This position is called the anthropic argument, and its validity is hotly debated.
35. What's Next for Cosmology?
The next 20 years in cosmology promise to be no less interesting than the last. New experiments are in the works to deepen our understanding in six areas: dark matter, dark energy, the universe's first billion years, galaxy evolution, inflation, and the early universe.
October 17, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapter 6. Atoms and Quantum Theory.
“EPR and Bell's Theorem”, clarification from Bill Daniel on Ch. 6's coverage of the Einstein, Podolsky, Rosen Paradox.
October 26, 2016
36. A Comprehensible Universe?
Why is it possible for us to understand the universe? Could our apparent comprehension be an illusion? There are good reasons to believe that we have authentic access to the deepest secrets of nature and that we should not be surprised to feel at home in the universe.
November 9, 2016
Having finished Whittle's Cosmology Course, the next 12 lectures will be from
“Black Holes Explained” by University of California, Berkeley Professor Alex Filippenko.
We'll start out assuming we will do one lecture per session but we may go faster. The schedule will be updated as we go.
Black Hole Lectures 1: A General Introduction to Black Holes, and 2: The Violent Deaths of Massive Stars.
November 21, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapter 6 (continued). Atoms and Quantum Theory.
“EPR and Bell's Theorem”, clarification from Bill Daniel on Ch. 6's coverage of the Einstein, Podolsky, Rosen Paradox,
and a paper from Dave on “Concrete Hidden Variables”.
December 14, 2016
Black Hole Lectures 3: Gamma-Ray Bursts–The Birth of Black Holes, and 4: Searching for Stellar-Mass Black Holes.
December 19, 2016 Book Discussion: Basic Concepts in Physics: From the Cosmos to Quarks, by Masud Chaichian. Chapter 7. Quantum Electrodynamics.
“The Dirac Equation”, from It Must Be Beautiful: Great Equations of Modern Science.
For more information, e-mail group leader Jeff Grove: jeff1.grove@gmail.com.
This is http://www.sackett.net/cosmologySchedule2016.htm, last updated January 8, 2017.