Astronomy 161 - Introduction to Solar System Astronomy 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.

  ...more

  

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• December 01, 2006Lecture 46: 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 200 planets have been found around 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

  Doppler Wobble, 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. The existance of a significant population of so-called

  "Hot Jupiters" may be telling us that planetary migration can be much

  more extreme that we saw in our own Solar System, or that these

  planetary system formed in a very different way than ours. It seems

  appropriate to end this class with more questions than answers, but

  that's where the science becomes most exciting. Recorded 2006 Dec 1 in

  100 Stillman Hall on the Columbus campus of The Ohio State University.

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• November 30, 2006Lecture 45: Is Pluto a Planet?

  What is a planet? Is Pluto a planet? This lecture traces the debate on

  the nature of what it means to be a planet by taking an historical approach,

  looking at how the question has arisen with the discovery of the asteroids and

  later Pluto and the Kuiper Belt. Many of the issued raised at the 2006

  IAU General Assembly meeting were raised two centuries before after the

  discovery of Ceres and Pallas. We will end with the new definition of a

  planet, and why Pluto is better understood as a Dwarf Planet, among the

  two largest objects of the class of small icy bodies of the outer solar

  system, than as the smallest of the planets. Recorded 2006 Nov 30 in

  100 Stillman Hall on the Columbus campus of The Ohio State University.

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• November 29, 2006Lecture 44: Comets

  Comets are occasional visitors from the icy reaches of the outer Solar

  System. This lecture discusses the orbits, structure, and properties of

  comets, and introduces the "dirty snowball" model of a comet nucleus.

  The end of class was a demo where I created a model of a comet nucleus

  from common household and office materials. Imagine a twisted

  combination of Alton Brown and Emeril Lagasse with a PhD in Astrophysics

  and you get the idea. We were not able to arrange for a videographer to

  come, but we did get some stills before the batteries died on the

  digital camera. The pictures are on the lecture webpage. The lecture

  is slightly abbreviated because we did the student evaluation of

  instruction surveys before class started. Recorded 2006 Nov 29 in 100

  Stillman Hall on the Columbus campus of The Ohio State University.

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• November 28, 2006Lecture 43: Icy Worlds of the Outer Solar System

  Beyond the orbit of Neptune is the realm of the icy worlds, ranging in

  size from Triton, the giant moon of Neptune, and the dwarf planets Pluto

  and Eris, all the way down to the nuclei of comets. 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

  2006 Nov 28 in 100 Stillman Hall on the Columbus campus of The Ohio

  State University.

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• November 27, 2006Lecture 42: Asteroids and Meteoroids

  Asteroids are the leftover rocky materials from the formation of the

  Solar System that reside mainly in a broad belt between the orbits of

  Mars and Jupiter. Meteoroids are fragments of asteroids or bits of

  debris from passing comets that occasionally pass through our atmosphere

  as meteors, and even more rarely survive the fiery passage to reach the

  ground as a meteorite. This lecture reviews the physical and dynamical

  (orbital) properties of Asteroids and Meteoroids, and discusses the role

  of Jupiter and orbital resonances in dynamically sculpting the Main

  Belt. Recorded 2006 Nov 27 in 100 Stillman Hall on the Columbus campus

  of The Ohio State University.

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• November 22, 2006Lecture 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

  physics - resonances and shepherd moons - that govern their evolution.

  Recorded 2006 Nov 22 in 100 Stillman Hall on the Columbus campus of The

  Ohio State University.

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• November 21, 2006Lecture 40: The Saturn System

  Saturn is attended by a system of 56 known moons and bright, beautiful

  rings. The Moon system is the focus of our attention today. Saturn has

  one giant moon, Titan, which is the 2nd largest moon in the Solar

  System, and the only one with a heavy atmosphere. On Titan, the

  atmosphere is mostly nitrogen and methane, but the temperature and

  pressure are such that methane plays the same role that water plays on

  the Earth: it can be either a solid, gas, or liquid. I will review

  tantalizing evidence from the Cassini and Huygens probes that there is,

  in fact, liquid methane and maybe even liquid methane lakes on Titan.

  Most of the other moons are ancient, icy, and heavily cratered -

  geologically dead worlds - but one, Enceladus, is a big surprise. 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 2006 Nov 21 in 100 Stillman Hall on the Columbus

  campus of The Ohio State University.

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• November 20, 2006Lecture 39: The Moons of Jupiter

  Jupiter is surrounded by a solar system in miniature of 63 known moons.

  Most (59) are tiny, irregular bodies that are a combination of captured

  asteroids and comets. The 4 largest are the giant Galilean Moons: Io,

  Europa, Ganymede, and Callisto. 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 2006 Nov 20 in 100 Stillman Hall on the

  Columbus campus of The Ohio State University.

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• November 16, 2006Lecture 38: Uranus and Neptune

  Uranus and Neptune are the smallest and outermost of the 4 Jovian

  planets. While superficially similar to Jupiter and Saturn, there are

  substantial differences. Uranus and Neptune have smaller rocky cores

  surrounded by deep, slushy ice mantles and relatively thinner hydrogen

  atmospheres, quite different from the massive cores and deep metallic

  hydrogen mantles of Jupiter and Saturn. We will also ask why they

  appear blue, look at their internal energy and weather, and then review

  the properties of the Jovian planets as a group. Recorded 2006 Nov 16

  in 100 Stillman Hall on the Columbus campus of The Ohio State

  University.

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