Astronomy 161 - Introduction to Solar System Astronomy - Autumn 2007

By Richard PoggeScience Education Courses Natural Sciences Astronomy

Astronomy 161 - Introduction to Solar System Astronomy - Autumn 2007 episodes

December 06, 2009 Astronomy 141 Podcast Teaser
A new podcast, Astronomy 141, Life in the Universe, is available
for those interested in continuing an exploration of topics in
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November 30, 2007 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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November 29, 2007 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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November 28, 2007 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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November 27, 2007 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.
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November 26, 2007 Lecture 42: Asteroids
Asteroids are the leftover rocky materials from the formation of the
Solar System that reside primarily in a broad belt between the orbits of
Mars and Jupiter. This lecture reviews the physical and orbital
properties of Asteroids, and discusses the role of Jupiter and orbital
resonances in dynamically sculpting the Main Belt of Asteroids. Once
again, we see how the history of the dynamical evolution of our Solar
System is written in the orbits of its members. Recorded 2007 Nov 26 in
1000 McPherson Lab on the Columbus campus of The Ohio State University.
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November 21, 2007 Lecture 41: Planetary Rings
All Jovian planets have rings. We are most familiar with the bright,
spectacular rings of Saturn, but the other Jovian planets have rings
systems around them. This lecture describes the different ring systems
and their properties, and discusses their origin, formation, and the
gravitational interactions - resonances, perturbations, and shepherd
moons - that govern their evolution. Recorded 2007 Nov 21 in 1000
McPherson Lab on the Columbus campus of The Ohio State University.
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November 20, 2007 Lecture 40: The Saturn System
Saturn is attended by a system of 60 known moons and bright, beautiful
rings. Today we will explore the moons of Saturn. Among the highlights
are Saturn's lone giant moon, Titan, the 2nd largest moon in the Solar
System and the only one with a heavy atmosphere. The atmosphere of
Titan is mostly nitrogen with a little methane, but the temperature and
pressure are such that methane plays the same role on Titan that water
plays on the Earth: it can be either a solid, gas, or liquid. The
Cassini and Huygens probes have recently shown that there is evidence of
liquid methane flows and mudflats, and even liquid methane lakes as big
as the Great Lakes or Caspian seas on Earth. The other moon of interest
is Enceladus. The shiniest object in the Solar System, Enceladus has
spectacular fountains - cryovolcanos - that spew water vapor from
reservoirs created in its tidally-heated interior. This ice repaves
much of the surface of Enceladus, giving it a young, shiny surface, and
builds the E ring of Saturn. Recorded 2007 Nov 20 in 1000 McPherson Lab
on the Columbus campus of The Ohio State University.
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November 19, 2007 Lecture 39: The Moons of Jupiter
Jupiter has its own personal solar system in miniature of 63 known
moons. Most are tiny, irregular bodies that are a combination of
captured asteroids and comets, but it is the 4 largest, the giant
Galilean Moons: Io, Europa, Ganymede, and Callisto, that is of greatest
interest to us in this lecture. Each is a fascinating world of its own,
with a unique history and properties: volcanically active Io, icy Europa
which may hide an ocean of liquid water beneath the surface, the grooved
terrain of Ganymede, and frozen dirty Callisto with the most ancient
surface of the four. Recorded 2007 Nov 19 in 1000 McPherson Lab on the
Columbus campus of The Ohio State University.
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November 15, 2007 Lecture 38: The Ice Giants - Uranus and Neptune
The Ice Giants Uranus and Neptune are the outermost major planets of our
Solar System. Internally they small rocky cores surrounded by deep,
slushy ice mantles and shallow hydrogen atmospheres, quite unlike the
massive cores and deep metallic hydrogen mantles of Jupiter and Saturn.
This lecture describes their basic properties: the origin of their vivid
blue/green colors, their composition, structure, and weather. At the
end we'll contrast and compare their properties to those of the Gas
Giants. Recorded 2007 Nov 15 in 1000 McPherson Lab on the Columbus
campus of The Ohio State University.
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