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 trigonometric parallaxes, and then
introduces the idea of Standard Candles, and how they are used to
develop methods for deriving Luminosity Distances based on the Inverse
Square Law of Brightness.  We will explore three luminosity-based
distance methods useful for studying our Galaxy and nearby galaxies:
Spectroscopic Parallaxes, Cepheid Variable Period-Luminosity Relation,
and the RR Lyrae P-L Relation.  Recorded 2006 February 6 in 1008 Evans
Laboratory on the Columbus campus of The Ohio State University.

Lecture 22: The Cosmic Distance Problem

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A new podcast, Astronomy 141, Life in the Universe, is available
for those interested in continuing an exploration of topics in
modern astronomy.

Astronomy 141 Podcast Teaser

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 University.

Lectures 1-4: An Explanation

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 Columbus campus of The Ohio State
University.

Welcome to Astronomy 162

How can we search for extraterrestrial intelligence, and what are we
looking for?  This second part of a 2-part lecture picks up where we
left off yesterday by examining SETI, the Search for ExtraTerrestrial
Intelligence, and reviews what we might look for and how.  We will use
this as a point of departure to then briefly review where we have come
and what we have learned in Astronomy 162, bringing this course to a
close for Winter Quarter 2006.  Recorded 2006 Mar 10 in 1008 Evans
Laboratory on the Columbus campus of The Ohio State University.

Lecture 44: Life, the Universe, and Everything (Life Part II)

Are we alone in the Universe?  This is the first part of a 2-part
lecture that will explore the question of life and the Universe.  We
will look at the conditions needed for life, and address the question of
how often we expect those conditions to be satisfied in our own Galaxy.
In this part, we introduce the Drake Equation and make some basic
estimates.  To be honest, it was supposed to be one lecture, but I ran
over time and ran into the bell.  Oops!  Very embarrasing.  Tomorrow's
lecture will finish up our discussion of life in the Universe, and then
wrap up Astronomy 162 for the quarter.  Recorded 2006 March 9 in 1008
Evans Laboratory on the Columbus campus of The Ohio State University.

Lecture 22: The Cosmic Distance Problem

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