Astrophysics: Frontiers and Controversies - Audio
by Charles Bailyn
To listen to an audio podcast, mouse over the title and click Play. Open iTunes to download and subscribe to iTunes U collections.
(ASTR 160) This course focuses on three particularly interesting areas of astronomy that are advancing very rapidly: Extra-Solar Planets, Black Holes, and Dark Energy. Particular attention is paid to current projects that promise to improve our understanding significantly over the next few years. The course explores not just what is known, but what is currently not known, and how astronomers are going about trying to find out. This course was recorded in Spring 2007.
||01 - Introduction||Professor Bailyn introduces the course and discusses the course material and requirements. The three major topics that the course will cover are (1) exoplanets--planets around stars other than the Sun, (2) black holes--stars whose gravitational pull...||10/9/2009||Free||View in iTunes|
||02 - Planetary Orbits||Exoplanets are introduced and students learn how astronomers detect their presence as well as the challenges associated with it. Physics equations are explained as well as their importance in the context of the course. A number of problems are...||10/9/2009||Free||View in iTunes|
||03 - Our Solar System and the Pluto Problem||Class begins with a review of the first problem set. Newton's Third Law is applied in explaining how exoplanets are found. An overview of the Solar System is given; each planet is presented individually and its special features are highlighted...||10/9/2009||Free||View in iTunes|
||04 - Discovering Exoplanets: Hot Jupiters||The formation of planets is discussed with a special emphasis on the bodies in the Solar System. Planetary differences between the celestial bodies in the Inner and Outer Solar System are observed. Professor Bailyn explains how the outlook of our ...||10/9/2009||Free||View in iTunes|
||05 - Planetary Transits||Professor Bailyn talks about student responses for a paper assignment on the controversy over Pluto. The central question is whether the popular debate is indeed a "scientific controversy." A number of scientific "fables" are discussed and a moral is ...||10/9/2009||Free||View in iTunes|
||06 - Microlensing, Astrometry and Other Methods||The class begins with a discussion on transits – important astronomical events that help astronomers to find new planets. The event occurs when a celestial body moves across the face of the star it revolves around and blocks some of its light.||10/9/2009||Free||View in iTunes|
||07 - Direct Imaging of Exoplanets||Class begins with a problem on transits and learning what information astronomers obtain through observing them. For example, radii of stars can be estimated. Furthermore, applying the Doppler shift method, one can find the mass of a star.||10/9/2009||Free||View in iTunes|
||08 - Introduction to Black Holes||The second half of the course begins, focusing on black holes and relativity. In introducing black holes, Professor Bailyn offers a definition, talks about how their existence is detected, and explains why (unlike in the case with exoplanets ...||10/9/2009||Free||View in iTunes|
||09 - Special and General Relativity||The discussion of black holes continues with an introduction of the concept of event horizon. A number of problems are worked out to familiarize students with mathematics related to black hole event horizons. In a longer question and answer session...||10/9/2009||Free||View in iTunes|
||10 - Tests of Relativity||The lecture begins with the development of post-Newtonian approximations from Newtonian terms. Several problems are worked out in calculating mass, force and energy. A discussion follows about how concepts like mass and velocity are ...||10/9/2009||Free||View in iTunes|
||11 - Special and General Relativity (cont.)||The lecture begins with a comprehensive overview of the historical conditions under which Einstein developed his theories. Of particular impact were the urgent need at the turn of the 19th century to synchronize clocks around the world; Einstein's...||10/9/2009||Free||View in iTunes|
||12 - Stellar Mass Black Holes||One last key concept in Special Relativity is introduced before discussion turns again to black celestial bodies (black holes in particular) that manifest the relativistic effects students have learned about in the previous lectures. The new concept...||10/9/2009||Free||View in iTunes|
||13 - Stellar Mass Black Holes (cont.)||Class begins with clarification of equations from the previous lecture. Four post-Newtonian gravitational effects are introduced and discussed in detail. The first of these is the so-called Perihelion Precession, which occurs when the major axis of a...||10/9/2009||Free||View in iTunes|
||14 - Pulsars||Professor Bailyn begins with a summary of the four post-Newtonian effects of general relativity that were introduced and explained last time: precession of the perihelion, the deflection of light, the gravitational redshift, and gravitational waves.||10/9/2009||Free||View in iTunes|
||15 - Supermassive Black Holes||The lecture begins with a question-and-answer session about black holes. Topics include the extent to which we are sure black holes exist in the center of all galaxies, how massive they are, and how we can observe them. The lecture then turns to...||10/9/2009||Free||View in iTunes|
||16 - Hubble's Law and the Big Bang||The third and final part of the course begins, consisting of a series of lectures on cosmology. A brief history of how cosmology developed into a scientific subject is offered. The discovery of dark energy, along with dark matter, played a crucial...||10/9/2009||Free||View in iTunes|
||17 - Hubble's Law and the Big Bang (cont.)||Class begins with a review of magnitudes and the problem set involving magnitude equations. Implications of the Hubble Law and Hubble Diagram are discussed. Professor Bailyn elaborates on the Big Bang theory of cosmology and addresses ...||10/9/2009||Free||View in iTunes|
||18 - Hubble's Law and the Big Bang (cont.)||Professor Bailyn returns to the subject of the expansion of the universe to offer explanations that do not require belief in the Big Bang theory. One alternative is a theory that, in the past, the entire universe was reduced to an "initial ...||10/9/2009||Free||View in iTunes|
||19 - Omega and the End of the Universe||Class begins with a review of the issues previously addressed about the origin and fate of the universe. The role of gravity in the expansion of the universe is discussed and given as the reason why the rate of expansion cannot remain constant ...||10/9/2009||Free||View in iTunes|
||20 - Dark Matter||This lecture introduces an important concept related to the past and future of the universe: the Scale factor, which is a function of time. With reference to a graph whose coordinates are the Scale factor and time, the problem of dark matter...||10/9/2009||Free||View in iTunes|
||21 - Dark Energy and the Accelerating Universe and the Big Rip||Class begins with a review of the mysterious nature of dark matter, which accounts for three quarters of the universe. Different models of the universe are graphed. The nature, frequency, and duration of supernovae are then addressed. Professor ...||10/9/2009||Free||View in iTunes|
||22 - Supernovae||Professor Bailyn offers a review of what is known so far about the expansion of the universe from observing galaxies, supernovae, and other celestial phenomena. The rate of the expansion of the universe is discussed along with the Big Rip theory...||10/9/2009||Free||View in iTunes|
||23 - Other Constraints: The Cosmic Microwave Background||Reasons for the expansion of the universe are addressed at the start of this lecture, focusing especially on the acceleration of dark energy. Supernovae were the first evidence for the existence of dark energy. Two other proofs are presented.||10/9/2009||Free||View in iTunes|
||24 - The Multiverse and Theories of Everything||Professor Bailyn begins the class with a discussion of a recent New York Times article about the discovery of a new, earth-like planet. He then discusses concepts such as epicycles, dark energy and dark matter; imaginary ideas invented to explain...||10/9/2009||Free||View in iTunes|
Good Lecturer and interesting class...
I have to start this saying that I am Math-phobic, yet Prof. Bailyn makes some VERY complicated math approachable... but it IS astrophysics so it's still complicated... It helps immensely that I am not worried about taking the midterm or the final.
He is a good lecturer and is animated and funny. Certainly entertaining enough to enjoy just listening to him. However, if you are trying to grasp the math at all, I suggest using the video version of this, although, even with the video you occasionally miss something (the camera is firmly focused on the overhead projector and you hear him say 'that means it goes this way' but you never see which way that is.
The subject matter is dead-on current. It is talking about the planets and the problems they present up to when this class was held. Fascinating stuff!
I would heartily suggest following this iTunesU selection.