How did we discover that the Universe is Expanding?  What does
it mean that it is expanding?  This lecture introduces Hubble's Law,
the observational evidence that the Universe is systematically
expanding.  As galaxies get more distant from us, the apparent speed
of recession gets larger in proportion.  The proportionality is the
rate of expansion, called the Hubble Parameter (H0).  This leads us
to the idea of expanding space, and the Cosmological Redshift, which
combined with the Hubble Law allows us a way to estimate very large
cosmic distances.  We will take up the more thorny issue of the
Cosmic Distance Scale in tomorrow's lecture.
Recorded 2006 February 23 in 1008 Evans Laboratory on the Columbus campus
of The Ohio State University.

Lecture 34: The Expanding Universe

Natural Sciences

Science & Medicine

Education

Training

Language Courses

Higher Education

K-12

Educational Technology

Science

Astronomy

Courses

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 34: The Expanding Universe

Download our free app to listen on your phone