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 96% of the universe. The Anthropic Principle is introduced and the possibility of the multiverse is addressed. Finally, biological arguments are put forth for how complexity occurs on a cosmological scale. The lecture and course conclude with a discussion on the fine differences between science and philosophy.
Other lectures from this course
Showing posts with label Yale Astrophysics. Show all posts
Showing posts with label Yale Astrophysics. Show all posts
Sunday, 12 February 2012
Sunday, 5 February 2012
Yale: Frontiers and Controversies in Astrophysics, Lecture 23
ASTR 160 - Frontiers and Controversies in Astrophysics
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
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. The first is the Cosmic Microwave Background, which is a form of electromagnetic radiation that is perfectly smooth and equal in all directions. It firmly supports the Big Bang theory. Projects attempting to measure it, such as COBE and WMAP, are discussed. Secondly, Large-Scale Clustering is introduced: by measuring the degree of clustering, astronomers hope to advance their understanding of dark energy and dark matter. Computer simulations of the evolution of the universe are shown.
Other lectures from this course
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
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. The first is the Cosmic Microwave Background, which is a form of electromagnetic radiation that is perfectly smooth and equal in all directions. It firmly supports the Big Bang theory. Projects attempting to measure it, such as COBE and WMAP, are discussed. Secondly, Large-Scale Clustering is introduced: by measuring the degree of clustering, astronomers hope to advance their understanding of dark energy and dark matter. Computer simulations of the evolution of the universe are shown.
Other lectures from this course
Monday, 9 January 2012
Yale: Frontiers and Controversies in Astrophysics, Lecture 22
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 and the balance of dark energy and dark matter in the universe over time. The point at which the universe shifts from accelerating to decelerating is examined. Worries related to the brightness of high redshift supernovae and the effects of gravitational lensing are explained. The lecture also describes current project designs for detecting supernovae at high or intermediate redshift, such as the Joint Dark Energy Mission (JDEM) and Large Synoptic Survey Telescope (LSST).
Other lectures from this course
Other lectures from this course
Friday, 30 December 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 21
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 Bailyn presents data from the Supernova Cosmology Project and pictures of supernovae taken by the Hubble Space Telescope. The discovery of dark energy is revisited and the density of dark energy is calculated. The Big Rip is presented as an alternative hypothesis for the fate of the universe.
Other lectures from this course
Other lectures from this course
Tuesday, 13 December 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 20
ASTR 160 - Frontiers and Controversies in Astrophysics
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
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 is addressed again. Cosmological redshifts are measured to determine the scale of the universe. The discovery of the repulsive, anti-gravitational force of dark energy is explained. The lecture concludes with discussion of Einstein's biggest mistake: the invention of the cosmological constant to balance gravity.
Other lectures from this course
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
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 is addressed again. Cosmological redshifts are measured to determine the scale of the universe. The discovery of the repulsive, anti-gravitational force of dark energy is explained. The lecture concludes with discussion of Einstein's biggest mistake: the invention of the cosmological constant to balance gravity.
Other lectures from this course
Sunday, 27 November 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 19
ASTR 160 - Frontiers and Controversies in Astrophysics
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
Omega and the End of the Universe
Omega is the actual density of the universe divided by its critical density: if it is greater than 1, there will be a big crunch; if it is lesse than 1, the universe will expand forever. Evaluating omega is not easy, partly because of dark matter (WIMPs:Weakly Interactive Massive Particles, and MACHOs: Massive Astrophysical Compact Halo Objects).
Other lectures from this course
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
Omega and the End of the Universe
Omega is the actual density of the universe divided by its critical density: if it is greater than 1, there will be a big crunch; if it is lesse than 1, the universe will expand forever. Evaluating omega is not easy, partly because of dark matter (WIMPs:Weakly Interactive Massive Particles, and MACHOs: Massive Astrophysical Compact Halo Objects).
Other lectures from this course
Tuesday, 8 November 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 18
ASTR 160 - Frontiers and Controversies in Astrophysics
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
Hubble's Law and the Big Bang
Other lectures from this course
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
Hubble's Law and the Big Bang
Other lectures from this course
Wednesday, 21 September 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 17
ASTR 160 - Frontiers and Controversies in Astrophysics
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
Professor Charles Bailyn
Spring 2007
Source: Yale University, Open Yale Courses
- Review of Magnitudes
- Implications of Hubble's Discoveries on the Aging Universe
- Conceptualizing a Three-Dimensional Universe
- Q&A: The Big Bang, the Expansion, and the Big Crunch
Monday, 1 August 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 16
Source: Yale University, Open Yale Courses
Lecture 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 role in the development of cosmology. The lecture then discusses the discovery of spiral nebulae in 1920, as well as the "Great Debate" over what they were. Hubble's famous redshift diagram is presented as the basis for Hubble's Constant and Big Bang cosmology. The difficulty of measuring distance of objects in space, and how to do it using the parallax method and the standard candle method, are discussed. Measure brightness using the magnitude scale is explained. Class ends with a review of logarithms.
00:00 - Chapter 1. Introduction to Cosmology
03:34 - Chapter 2. Spiral Nebulae and Hubble's Redshift Diagram
17:35 - Chapter 3. Measuring the Distance of a Star: The Parallax Method
25:13 - Chapter 4. Measuring Brightness: The Standard Candle Method
38:06 - Chapter 5. Absolute and Apparent Magnitude
48:04 - Chapter 6. Conclusion
Other lectures from this course
Lecture 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 role in the development of cosmology. The lecture then discusses the discovery of spiral nebulae in 1920, as well as the "Great Debate" over what they were. Hubble's famous redshift diagram is presented as the basis for Hubble's Constant and Big Bang cosmology. The difficulty of measuring distance of objects in space, and how to do it using the parallax method and the standard candle method, are discussed. Measure brightness using the magnitude scale is explained. Class ends with a review of logarithms.
00:00 - Chapter 1. Introduction to Cosmology
03:34 - Chapter 2. Spiral Nebulae and Hubble's Redshift Diagram
17:35 - Chapter 3. Measuring the Distance of a Star: The Parallax Method
25:13 - Chapter 4. Measuring Brightness: The Standard Candle Method
38:06 - Chapter 5. Absolute and Apparent Magnitude
48:04 - Chapter 6. Conclusion
Other lectures from this course
Thursday, 14 July 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 15
Source: Yale University, Open Yale Courses
Supermassive Black Holes
00:00 - Supermassive Black Holes and Gravitational Waves
07:15 - Strong-Field Relativity
17:01 - X-Rays of Binary Stars
30:08 - Finding Black Holes with X-Rays
46:43 - Conclusion
Other lectures from this course
Supermassive Black Holes
00:00 - Supermassive Black Holes and Gravitational Waves
07:15 - Strong-Field Relativity
17:01 - X-Rays of Binary Stars
30:08 - Finding Black Holes with X-Rays
46:43 - Conclusion
Other lectures from this course
Friday, 17 June 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 14
Source: Yale University, Open Yale Courses
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. The concept of gravitational lensing is discussed as predicted by Einstein's general relativity theory. The formation of a gravitational lens can be observed when light from a bright distant source bends around a massive object between the source (such as a quasar) and the observer. Professor Bailyn then offers a slideshow of gravitational lenses. The issue of finding suitable astronomical objects that lend the opportunity to observe post-Newtonian relativistic effects is addressed. The lecture ends with Jocelyn Bell and the discovery of pulsars.
Suggestion for the cameraman: when the teacher is commenting a picture, show the picture, not the teacher!
See other lectures in this series.
Sunday, 29 May 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 13
Source: Yale University, Open Yale Courses
Four post-Newtonian gravitational effects are introduced. The first of these is the Perihelion Precession, which occurs when the major axis of a planet's elliptical orbit precesses within its orbital plane, in response to changing gravitational forces exerted by other planets. Secondly, deflection of light is described as the curving of light as it passes near a large mass. Gravitational redshift is explained as a frequency effect that occurs as light moves away from a massive body such as a star or black hole. Finally, the existence and effects of gravitational waves are discussed.
See other lectures in this series.
Four post-Newtonian gravitational effects are introduced. The first of these is the Perihelion Precession, which occurs when the major axis of a planet's elliptical orbit precesses within its orbital plane, in response to changing gravitational forces exerted by other planets. Secondly, deflection of light is described as the curving of light as it passes near a large mass. Gravitational redshift is explained as a frequency effect that occurs as light moves away from a massive body such as a star or black hole. Finally, the existence and effects of gravitational waves are discussed.
See other lectures in this series.
Sunday, 1 May 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 12
Source: Yale University, Open Yale Courses
Metrics in general relativity, Schwarzschild metric, perihelion precession of Mercury.
See other lectures in this series.
Metrics in general relativity, Schwarzschild metric, perihelion precession of Mercury.
See other lectures in this series.
Monday, 25 April 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 11
Source: Yale University, Open Yale Courses
General relativity, curvature of space time.
See other lectures in this series.
General relativity, curvature of space time.
See other lectures in this series.
Thursday, 7 April 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 10
Source: Yale University, Open Yale Courses
This particular lecture is about introductory special relativity (there is no real application to astrophysics).
See other lectures in this series.
This particular lecture is about introductory special relativity (there is no real application to astrophysics).
See other lectures in this series.
Saturday, 19 March 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 9
Source: Yale University, Open Yale Courses
This lecture is titled "Special and General Relativity", but this subject is introduced in the last 10 minutes. Before that, professor Bailyn talks about the event horizon and answers several random questions about black holes.
See other lectures in this series.
This lecture is titled "Special and General Relativity", but this subject is introduced in the last 10 minutes. Before that, professor Bailyn talks about the event horizon and answers several random questions about black holes.
See other lectures in this series.
Tuesday, 8 March 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 8 (Introduction to Black Holes)
Source: Yale University, Open Yale Courses
Black holes, escape velocity, Schwarzchild radius. Birth of a black hole: star in hydrostatic equilibrium, white dwarf, Chandrasekhar limit, neutron star.
See other lectures in this series.
Black holes, escape velocity, Schwarzchild radius. Birth of a black hole: star in hydrostatic equilibrium, white dwarf, Chandrasekhar limit, neutron star.
See other lectures in this series.
Saturday, 19 February 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 7
Source: Yale University, Open Yale Courses
Third method to detect exoplanets: astrometry (and comparison with other methods: radial velocity and transit). In the last 10 minutes: presentation of some upcoming projects: Kepler mission (transits), SIM mission (astrometry), Terrestrial Planet Finder (direct planet imaging).
See other lectures in this series.
Third method to detect exoplanets: astrometry (and comparison with other methods: radial velocity and transit). In the last 10 minutes: presentation of some upcoming projects: Kepler mission (transits), SIM mission (astrometry), Terrestrial Planet Finder (direct planet imaging).
See other lectures in this series.
Thursday, 10 February 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 6
Source: Yale University, Open Yale Courses
Finding planets from transits: some planets are discovered when they partially obscure light coming from star. Planetary migration.
See other lectures in this series.
Finding planets from transits: some planets are discovered when they partially obscure light coming from star. Planetary migration.
See other lectures in this series.
Saturday, 29 January 2011
Yale: Frontiers and Controversies in Astrophysics, Lecture 5
Source: Yale University, Open Yale Courses
First 10 minutes: some comments about assignment "Is the controversy about Pluto a scientific controversy?"; science can be affected by culture. Motion of star and planet around the center of mass. Graph of radial velocities interpreted as a system containing 3 planets. Back to "hot jupiters": discovery of 51 Peg b shows the importance of "expecting the unexpected". Alternative explanations of hot jupiters (double star systems, pulsating stars) proved wrong.
See other lectures in this series.
First 10 minutes: some comments about assignment "Is the controversy about Pluto a scientific controversy?"; science can be affected by culture. Motion of star and planet around the center of mass. Graph of radial velocities interpreted as a system containing 3 planets. Back to "hot jupiters": discovery of 51 Peg b shows the importance of "expecting the unexpected". Alternative explanations of hot jupiters (double star systems, pulsating stars) proved wrong.
See other lectures in this series.
Subscribe to:
Posts (Atom)