Astronomy 162 - Stars, Galaxies, & the Universe

Lectures 1-4: An Explanation

Where are Lectures 1-4? This is a good question, and one I've gotten from many listeners. Here's the answer. Recorded 2006 Nov 27 on the Columbus campus of The Ohio State

Welcome to Astronomy 162

Welcome to the Astronomy 162 Lecture Podcasts! This is a brief message from me explaining the podcasts, and welcoming new and old listeners. Recorded 2006 Mar 10 on the C

Lecture 22: The Cosmic Distance Problem

How do we measure distances to astronomical objects that are too far away to use Trigonometric Parallaxes? This first lecture of Unit 4 reviews geometric methods like tri

Lecture 21: Testing Stellar Evolution

What are our observational tests of Stellar Evolution? This lecture discusses how we use Hertzsprung-Russell Diagrams of star clusters to test stellar evolution theory, a

Lecture 20: Black Holes

What happens if even Neutron Degeneracy pressure is insufficient to halt the collapse of gravity? In that case, the object simply collapses in upon itself, approaching a

Lecture 19: Extreme Stars: White Dwarfs & Neutron Stars

What happens to the cores left behind at the end of a star's life? This lecture introduces these stellar remnants: White Dwarfs (remnants of low-mass stars held up by Ele

Lecture 18: Supernovae

Once a massive star builds a massive Iron/Nickel core at the end of the Silicon Burning day, it is doomed. A catastrophic core collapse is followed by explosive ejection

Lecture 17: The Evolution of High-Mass Stars

What happens when a high-mass (more than 4 solar masses) Main Sequence stars runs out of Hydrogen in its core. At first the internal evolution looks like that of a low-ma

Lecture 16: The Evolution of Low-Mass Stars

What happens to a low-mass star (less than 4 solar masses) when it runs out of core Hydrogen and must leave the Main Sequence. This lecture describes the changes inside a

Lecture 15: The Main Sequence

What are the properties of stars on the Main Sequence? This lecture discusses what happens to a star after it alights onto the Main Sequence, burning H to He in its core,

Lecture 14: Star Formation

How do stars form? The Sun is old and in Hydrostatic and Thermal equilibrium. How did it get that way? This lecture presents the basic steps of star formation as a progre

Lecture 13: Energy Generation and Transport in Stars

How do stars generate energy in their cores, and once made, how is that energy transported to the surface where it can be radiated away as Luminosity? This lecture revisi

Lecture 12: As Long as the Sun Shines

How long can the Sun continue to shine, and what source of energy does it tap to keep shining? This lecture answers this question by introducing two important energy sour

Lecture 11: The Internal Structure of Stars

What are the physical laws that determine the internal structure of stars? We first introduce the Mass-Luminosity Relation for Main Sequence stars, as well as seeing how

Lecture 10: Synthesis: The Herzsprung-Russell Diagram

How are all of the observed properties of stars (Luminosity, Mass, Radius, Temperature and Spectral Type) related to one another? This lecture introduces the Herzsprung-R

Lecture 09: Stellar Spectra

What do the spectra of stars look like, and what can they tell us about stellar properties? This lecture introduces the idea of stellar color, gives a brief overview of t

Lecture 08: Stellar Masses & Radii

How do we measure the masses and radii of stars? This lecture describes the three basic types of binary stars, and how each are used to measure the masses of stars. Deta

Lecture 07: Stellar Brightness

How do we quantify stellar brightness? This lecture introduces the inverse square-law of apparent brightness, the relation between Luminosity and Apparent Brightness, int

Lecture 06: The Motions of the Stars

The "fixed stars" are really in constant motion, but these motions are too small to see with the human eye in a human lifetime. This lecture introduces proper motions (ap

Lecture 05: Distances of the Stars

How do we measure the distances to the stars? This lecture introduces the method of trigonometric parallaxes and the units of the Parsec and Light Year. Recorded 2006 Jan