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Cosmology: The History and Nature of Our Universe

Discover a wealth of insights into the origin, evolution, composition, and probable fate of our universe in this insightful course by an award-winning professor.

Cosmology: The History and Nature of Our Universe is rated 4.8 out of 5 by 186.
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Rated 1 out of 5 by from A Failed Cosmology-Philosophy Hybrid This 2008 course is well illustrated and easily followed. Whittle’s lecture approach is reminiscent of an attorney carefully building a case. His slow, halting speech (using the 1.25 "play speed" is quite useful) is accompanied by a vaguely ‘romantic' infatuation with his material and an excited, “hopping” body language. All of this puts one on guard that a pet theory is coming and by Lecture 3 [=L3], we see our first hint: "What might the cosmological principle mean emotionally?” More follow. L5: Total mass-energy = mass + gravitational energy = 0, has “kind of a spiritual" flavor. It also introduces his main scientific argument that “vacuum energy expands inflation." L17 attempts to increase our buy-in via “material rarely shown to non-specialists” including that galactic roughness began with quantum inflation effects. [The rigorous Great Course “Physics and Our Universe by Wolfson” (less dramatically and more mathematically) supports this.] L18 contains a very nice discussion of dark matter/light matter forming "casts" to form suns and micro galaxies. L18-27 are pretty standard cosmological arguments and L28 provides a nice summary of them. Whittle’s POV provides a different “viewpoint” that may be quite helpful wherever one’s understanding is a bit tenuous from other courses. L27, however, contains a seemingly innocuous capitalization error that will haunt the course and lead to an attorney-like closing argument climax in L36: “Nature 'thinks' enormously faster than we do, and those first nanoseconds...were like geologic eons to Nature." According to an online Thesaurus, the only possible reason for capitalization of nature is if we consider Nature to be a person. Although writing: “Nature ‘thinks’..." implies personhood, Whittle’s simultaneous separation of thought from nature implies a lack of personhood. His confusion amplifies itself in L29: “How does Nature know what to do, in just the right way, and where does the knowledge reside?” He suggests knowledge is "…embedded in the vacuum”. So perhaps Vacuum should be capitalized? Regretfully, this seems to be another secular/borderline cultic circular reasoning blooper. L32 on the expansion of quantum fluctuations is probably compatible with Wolfson’s mathematical models except it adds: "the end of inflation (causes) vacuum energy to drop and the expansion slows down". Contrarily, Wolfson, while crediting Guth's 1980 proposal of cosmic inflation that eventually slows expansion down, doesn't ignore the 1998 discovery that the universe is actually now re-accelerating (L59, L60 and others). The Great Course "Theory of Everything" by Don Lincoln (Senior Scientist at the Fermi National Accelerator Lab) agrees with Wolfson. From L33 on, Whittle veers into increasing supposition. L33 suspects that dense vacuums arise from quantum fluctuations in "pre-inflation field seeds"...leading to the possibility of (sci-fi) "multiverses”. He has again crossed from science into a pseudo-religious secularism. Science requires that theories fit data, not suppositional "data" be created to fit theory. While L34 correctly marvels that “our universe and its physical laws seems fine-tuned for life", his “God of the gaps" argument is used to denigrate the concept of God by saying “it also raises the new question of how the creator was created. This becomes another circular argument since the sentence also contains a similarly capitalized “Nature", raising the question of how Nature was created. It also places God and Nature in equivalent blurred confusion. L36 purports to teach that modern cosmology stories “connect us to Nature and the gods": such capitalization ignores the above circular reasoning, and this time places the god Nature above “the gods”. CONCLUSION: Our “attorney” then attempts his closing arguments: cosmology provides " a broader sense of kinship with all atomic matter” and “we're children of Nature". Unfortunately, such an emotional closure seems directly out of Fallout’s infamous "Children of the Atom Zealot Congregation". Such are the contradictory perils of secularism…but they do not belong in a science course. Buy Wolfson or Lincoln instead.
Date published: 2024-02-26
Rated 5 out of 5 by from Absolutely Outstanding Course Professor Whittle provides a deep and illuminating understanding of our knowledge of Cosmology in these 36 lectures. For those of us who have a scientific background, there is mathematics which explains the concepts, while at the same time, not being absolutely necessary to understand the basic concepts for those without a math background. I absolutely loved this course, and would recommend to anyone who wants to understand the nature and origin of the universe.
Date published: 2023-12-29
Rated 2 out of 5 by from Great course two decades ago Outdated. These courses have a shelf life and the company needs to come to grips with that and plan for regular updates.
Date published: 2023-10-17
Rated 5 out of 5 by from Understandable to laymen & scientists alike He explains everything with examples & analogies, but also gives the mathematical formulas for calculating aspects of cosmology. My only complaint is that he doesn't always tell you what each symbol is for.
Date published: 2022-10-28
Rated 5 out of 5 by from A Required Course I believe every high school or college student should have to take a course just like this one. I have walked away from this course with humility and reverence toward our universe/multiverse! Dr. Mark Whittle is an amazing instructor and made the material very accessible. I especially appreciate his keeping the human dimension as bookends. This course has inspired me to keep up with the latest developments in the field and to deepen my knowledge. Thank you, Professor Whittle, and thank you Great Courses!!
Date published: 2022-08-19
Rated 5 out of 5 by from Absolutely great! This is the best cosmology course as an introductory review so far. It was the first time I saw that creating a fundamental course could be done with minimum math. Do not expect to get out of it with a diploma in cosmology but rather get inspired by this beautiful teaching work to start learning the subject deeper.
Date published: 2022-07-31
Rated 5 out of 5 by from The best of the Great Courses I liked this so much that I gave it to a grandson and bought another (streamng) copy. It should, however be updated in light of recent developments. I've read Steve Weinberg's "Cosmology" (as well as tutoring for him in graduate quantum mechanics) and older "Gravitation and Cosmology," and this is an excellent beginning introductiopn to the topic.
Date published: 2022-07-27
Rated 5 out of 5 by from Really Superb This is a marvelous course taught by a marvelous teacher. He goes through even the most complicated ideas at an understandable pace. I have watched other courses on the topics covered and can say that Dr. Whittle's explanation of how cosmic distances are determined, how quickly physical processes can occur, and what happens when galaxies collide are the best I have encountered. His explanation of the big bang and inflation is better than that of a newer course on this topic. After viewing this course I would suggest looking at Dr. Lincoln's course on the Evidence for Modern Physics to be brought up to date on findings since Dr. Kittle's course was produced.
Date published: 2022-04-14
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Discover a wealth of insights into the origin, evolution, composition, and probable fate of our universe. In the 36 lectures of Cosmology: The History and Nature of Our Universe, astronomer and award-winning Professor Mark Whittle makes this profound subject understandable and awe inspiring. With the aid of more than 1,700 vivid illustrations, discover how this scientific field has helped us decipher mysteries about the cosmos including dark matter and dark energy, cosmic inflation, and the birth of galaxies. Filled with keen looks at cosmology's breathtaking discoveries, this course is the perfect introduction to a fascinating field of study.


Mark Whittle

Creating my course on cosmology required me to see ourselves and our world as true cosmic citizens. I hope those who watch my course will also begin to see themselves from this new cosmic perspective.


University of Virginia

Dr. Mark Whittle is Professor of Astronomy at the University of Virginia, where he has been teaching since 1986. He teaches on the solar system, stars, galaxies, cosmology, and observing techniques. He also gives frequent public lectures, and he is committed to community outreach on all areas of astronomy, particularly cosmology. Professor Whittle's research centers on various aspects of nuclear activity in galaxies, a phenomenon that arises from gas falling onto supermassive black holes. His most recent work focuses on the properties of jets that emerge from Seyfert galaxies and the role they play in energizing the central few thousand light-years. Professor Whittle uses both optical and radio telescopes for his research, including the Hubble Space Telescope. Professor Whittle was a Mackinnon Scholar at Magdalen College, University of Oxford, where he obtained his B.A. Honors in Physics, First Class. He earned his M.A. in Physics at Oxford and his Ph.D. in Astronomy at the University of Cambridge.

Cosmology: The History and Nature of Our Universe


The Journey Ahead

01: 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.

30 min
Denizens of the Universe

02: 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.

30 min
Overall Cosmic Properties

03: 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.

30 min
The Stuff of the Universe

04: 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—96%—is dark energy and dark matter. The relative amounts of these constituents have changed as the universe has expanded.

32 min
The Sweep of Cosmic History

05: 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.

31 min
Measuring Distances

06: 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.

31 min
Expansion and Age

07: 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."

32 min
Distances, Appearances, and Horizons

08: 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.

32 min
Dark Matter and Dark Energy—96%!

09: 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.

31 min
Cosmic Geometry—Triangles in the Sky

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°. This lecture discusses the success at measuring the curvature of the universe in 1998.

33 min
Cosmic Expansion—Keeping Track of Energy

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.

31 min
Cosmic Acceleration—Falling Outward

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.

32 min
The Cosmic Microwave Background

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.

31 min
Conditions during the First Million Years

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.

32 min
Primordial Sound—Big Bang Acoustics

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.

33 min
Using Sound as Cosmic Diagnostic

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.

29 min
Primordial Roughness—Seeding Structure

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.

31 min
The Dark Age—From Sound to the First Stars

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.

30 min
Infant Galaxies

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.

28 min
From Child to Maturity—Galaxy Evolution

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.

30 min
Giant Black Holes—Construction and Carnage

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.

30 min
The Galaxy Web—A Relic of Primordial Sound

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.

30 min
Atom Factories—Stellar Interiors

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.

31 min
Understanding Element Abundances

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.

31 min
Light Elements—Made in the Big Bang

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.

31 min
Putting It Together—The Concordance Model

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.

32 min
Physics at Ultrahigh Temperatures

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.

29 min
Back to a Microsecond—The Particle Cascade

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.

31 min
Back to the GUT—Matter and Forces Emerge

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.

31 min
Puzzling Problems Remain

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.

30 min
Inflation Provides the Solution

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.

29 min
The Quantum Origin of All Structure

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.

31 min
Inflation's Stunning Creativity

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.

31 min
Fine Tuning and Anthropic Arguments

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.

29 min
What's Next for Cosmology?

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.

30 min
A Comprehensible Universe?

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.

33 min