Astronomy 161 - Introduction to Solar System Astronomy - Autumn 2007
Richard Pogge
Astronomy 161, Introduction to the Solar System, is the first quarter of
a 2-quarter introductory Astronomy for non-science majors taught at The
Ohio State Univ...
A new podcast, Astronomy 141, Life in the Universe, is available
for those interested in continuing an exploration of topics in
modern astronomy.
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Lecture 46: Are We Alone? Life in the Universe
Are we alone in the Universe? This lecture explores the question of how
we might go about finding life on planets around other stars. Rather
than talking about speculative ideas, like the Drake Equation or SETI, I
am instead taking the approach of posing it as a problem of what to look
for among the exoplanets we have been discovering in huge numbers in the
last decade. I describe the basic requirements for life, and
how life on Earth is surprisingly tough (extremophiles). I then give a
definition of the Habitable Zone around a star, and present the
Goldilocks Problem of how a planet must be neither too hot, too cold
(for liquid water) or too big or too small to be hospitable to
life. From there I then review the problem of how to go about finding
Earth-like planets (Pale Blue Dots) around other stars, and if we do
find them, what spectroscopic signatures of life, called biomarkers, we
can look for to see if they have some form of life like we understand it
on them. Recorded on 2007 Nov 30 in 1000 McPherson Lab on the Columbus
campus of The Ohio State University. This is the final lecture for
Autumn Quarter 2007.
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Lecture 45: Exoplanets - Planets Around Other Stars
Are there planets around other stars? Are there Earth-like planets
around other stars? Do any of those harbor life? Intelligent life?
We'd like to know the answers to all of these questions, and in recent
years we've made great progress towards at least answering the first.
To date, more than 260 planets have been found around more than 200
other stars, most in the interstellar neighborhood of the Sun, but a few
at great distance. This lecture reviews the search for ExoPlanets,
discussing the successful Radial Velocity, Transit, and Microlensing
techniques. What we have found so far are very suprising systems,
especially Jupiter-size or bigger planets orbiting very close (few
hundredths of an AU) from their parent stars. Recorded 2007 Nov 29 in
1000 McPherson Lab on the Columbus campus of The Ohio State University.
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Lecture 44: Comets
Comets are chance visitors from the icy reaches of the outer Solar
System. In this lecture I describe the properties of comets, their
historical importance, and introduce the "dirty snowball" model of a
comet nucleus. At the end of class I created a model of a comet nucleus
from common household and office materials, unfortunately I could not
arrange for a videographer in time. Recorded 2007 Nov 28 in 1000
McPherson Lab on the Columbus campus of The Ohio State University.
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Lecture 43: Icy Worlds of the Outer Solar System
Beyond the orbit of Neptune lies the realm of the icy worlds, ranging in
size from Neptune's giant moon Triton and the dwarf planets Pluto and
Eris, all the way down to the nuclei of comets a few kilometers across.
This lecture discussed the icy bodies of the Trans-Neptunian regions of
the Solar System, discussing the basic properties of Triton (the best
studied such object), Pluto, Eris, and the Kuiper Belt, introducing the
dynamical families of Trans-Neptunian Objects that record in their
orbits the slow migration of Neptune outwards during the early history
of the Solar System. The Kuiper Belt is the icy analog of the main
Asteroid Belt of the inner Solar System: both are shaped by their
gravitational interaction with giant gas planets (Jupiter for the
asteroids, Neptune for the KBOs), and are composed of leftover raw
materials from the formation of their respective regions of the Solar
System. Recorded 2007 Nov 27 in 1000 McPherson Lab on the Columbus
campus of The Ohio State University.
Sobre Astronomy 161 - Introduction to Solar System Astronomy - Autumn 2007
Astronomy 161, Introduction to the Solar System, is the first quarter of
a 2-quarter introductory Astronomy for non-science majors taught at The
Ohio State University. This podcast presents audio recordings of
Professor Richard Pogge's lectures from his Autumn Quarter 2007 class.
All of the lectures were recorded live in 1000 McPherson Laboratory on
the OSU Main Campus in Columbus, Ohio.
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