23 – How to Live Given the Certainty of Death

23 – How to Live Given the Certainty of Death

By |

Podcast: Play in new window | Download (Duration: 46:35 — 42.6MB) | Embed

Subscribe: Email | RSS

In this lecture, Professor Kagan invites students to pose the question of how one should live life knowing that it will certainly end in death. He also explores the issue of how we should set our goals and how we should go about achieving them, bearing in mind the time constraints. Other questions raised are how this ultimately affects the quality of our work and our accomplishments, as well as how we decide what is worth doing in life.

20 – Dark Matter

20 – Dark Matter

By |

Podcast: Play in new window | Download (Duration: 49:37 — 45.4MB) | Embed

Subscribe: Email | RSS

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.

22 – Fear of Death

22 – Fear of Death

By |

Podcast: Play in new window | Download (Duration: 47:49 — 43.8MB) | Embed

Subscribe: Email | RSS

Professor Kagan explores the issue of how thinking about death may influence the way we live. Fear as an emotional response to death is discussed as well as whether it is appropriate and under what conditions. A distinction is made between fear of the process of dying, and fear of death itself and what may come when one is dead. Finally, a number of other negative emotions are considered as possible appropriate responses to death and dying, such as anger, sadness, and sorrow.

19 – Omega and the End of the Universe

19 – Omega and the End of the Universe

By |

Podcast: Play in new window | Download (Duration: 49:10 — 45.0MB) | Embed

Subscribe: Email | RSS

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 and will eventually slow down. The actual density of the universe is calculated using various methods. Finally, the unsolved problem of dark matter is addressed and two explanatory hypotheses are proposed. One is that the universe is comprised of WIMPs (Weakly Interactive Massive Particles) that fulfill two requirements: they have mass and do not interact with light. The second hypothesis is that dark matter is made of MACHOs (Massive Astrophysical Compact Halo Objects), which scientists have attempted to identify through gravitational lenses.

21 – Other Bad Aspects of Death, Part II

21 – Other Bad Aspects of Death, Part II

By |

Podcast: Play in new window | Download (Duration: 49:47 — 45.6MB) | Embed

Subscribe: Email | RSS

Further bad aspects of death are considered, including ubiquity, or the fact that death may occur at any time and strike anyone. Professor Kagan invites students to contemplate the possibility of death-free time periods, vacation spots, and activities. Then there is consideration of the value of the human condition, which consists of life, followed by death. Finally, the question is raised as to whether it could be appropriate to refuse to face the facts about our mortality. Professor Kagan distinguishes between two ways in which thinking about these could influence human behavior. On the one hand, it may give one the reason to behave differently; on the other hand, it may just cause a change in behavior.

18 – Hubble’s Law and the Big Bang pt 3

18 – Hubble’s Law and the Big Bang pt 3

By |

Podcast: Play in new window | Download (Duration: 50:13 — 46.0MB) | Embed

Subscribe: Email | RSS

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 singularity,” in which everything was much closer, and therefore denser and hotter. Since the universe is in constant flux, however, it follows that in the future things will drift apart. The Steady State explanation for the expansion of the universe is then explained. Coined as a derogatory term meant to ridicule supporters of the Big Bang theory, Steady State purports that new energy and matter are constantly created as the universe expands, to fill in the void that results from the expansion. The discovery of quasars refuted the Steady State theory. The lecture ends with a discussion of how observing very distant objects allows us to look back in time, and also gives us a glimpse into the future of galaxies and the universe.

20 – The Value of Life, Part II; Other Bad Aspects of Death, Part I

20 – The Value of Life, Part II; Other Bad Aspects of Death, Part I

By |

Podcast: Play in new window | Download (Duration: 50:39 — 46.4MB) | Embed

Subscribe: Email | RSS

Lecture 20 continues the discussion of the value of life. It considers the neutral container theory, which holds that the value of life is simply a function of its contents, both pleasant and painful, and contrasts this with the valuable container theory, which assigns value to being alive itself. The lecture then turns to a consideration of some of the other aspects of death that may contribute to the badness of death. Among the issues addressed are the inevitability, variability and unpredictability of death.

17 – Hubble’s Law and the Big Bang pt 2

17 – Hubble’s Law and the Big Bang pt 2

By |

Podcast: Play in new window | Download (Duration: 51:51 — 47.5MB) | Embed

Subscribe: Email | RSS

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 controversial questions related to the age, development, and boundaries of the universe. The fate of the universe, and possibly its end (known as the Big Crunch) are addressed. Imagining an expanding three-dimensional universe is proposed. The lecture ends with a question-and-answer session during which students inquire about a variety of topics related to cosmology, such as the center of the universe, its current expansion, and hypothetical collapse.

19 – Immortality Part II; The Value of Life, Part I

19 – Immortality Part II; The Value of Life, Part I

By |

Podcast: Play in new window | Download (Duration: 49:01 — 44.9MB) | Embed

Subscribe: Email | RSS

The lecture begins with further exploration of the question of whether it is desirable to live forever under the right circumstances, and then turns to consideration of some alternative theories of the nature of well-being. What makes a life worth living? One popular theory is hedonism, but the thought experiment of being on an “experience machine” suggests that this view may be inadequate.

16 – Hubble’s Law and the Big Bang

16 – Hubble’s Law and the Big Bang

By |

Podcast: Play in new window | Download (Duration: 50:48 — 46.5MB) | Embed

Subscribe: Email | RSS

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.