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

• December 06, 2009Astronomy 141 Podcast Teaser

  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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• November 30, 2007Lecture 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, 2007Lecture 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, 2007Lecture 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, 2007Lecture 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, 2007Lecture 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, 2007Lecture 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.

  ...more

  

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• November 20, 2007Lecture 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, 2007Lecture 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, 2007Lecture 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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