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PH1600: Introductory Astronomy
Lecture 9: Saturn & Neptune
PH1600: Introductory Astronomy
Lecture 9: Saturn & Neptune
Next Lecture: Pluto, Dwarf Planets, and Comets
School: Michigan Technological University
Professor: Robert Nemiroff
Online Course WebCT pages:
http://courses.mtu.edu/
This class can be taken online ONLY, class
attendance is not required!
You are responsible for…
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Lecture material
Listed wikipedia entries
 But not higher math
APODs posted during the semester
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APOD review every week during lecture
Completing the Quizzes
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Homework quizzes 1, 2, 3 & 4 already due
Homework 5 will be released today
See WebCT at http://courses.mtu.edu/
Wikipedia entries:
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Saturn
Rings of Saturn
Titan_(moon)
Enceladus_(moon)
Cassini-Huygens
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Neptune
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Jovian Planets
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Jupiter, Saturn, Uranus, Neptune
Large massive planets
Rings
Many moons
Expansive and thick gaseous
atmospheres
Planets in the West
Credit & Copyright: Jimmy Westlake (Colorado Mountain College)
APOD: 2005 June 24
Planets and Fire by Moonlight
Credit & Copyright: Dmitrii Zagorodnov
APOD: 2008 July 9
Saturn
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Planet
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Second largest planet after Jupiter
d=9.5 Earths, r=9.5 AU, P=29.5 years
Average density less than water
Visited by Voyager 1 & 2 in 1980s
Saturn’s Rings
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Made of many small particles inside Roche
limit
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Small pebbles to car sized particles
Razor thin: 80,000 km radius; 10 meters
thick
Several different rings affected by
different moons
Cassini division between A and B rings
A Shadow on the Rings of Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2004 July 21
The Seasons of Saturn
APOD: 2003 April 5
NASA/JPL/Space Science Institute
Cassini Images Saturn's A Ring
Credit: UVIS, U. Colorado, ESA, NASA
APOD: 2004 July 12
Movie: Cassini Crosses Saturn's Ring Plane
Credit: NASA / JPL / SSI ; Animation: Gordan Ugarkovic & Emily Lakdawalla
APOD: 2007 January 31
Saturn in Blue and Gold
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2006 May 3
Mysterious Spokes in Saturn's Rings
Credit: CICLOPS, JPL, ESA, NASA
APOD: 2006 November 27
In the Shadow of Saturn
Credit: CICLOPS, JPL, ESA, NASA
APOD: 2006 October 16
Saturn: Atmosphere
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Mostly hydrogen, some helium,
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Trace amounts of other elements
Rotates one in 10 hours
Hurricane-like storms but no Great
Red Spot
Winds at 1800 km/hr
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Four times faster than Jupiter
Saturn Rotates
Credit: HST, NASA
APOD: 2000 October 3
Storm Alley on Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2004 November 2
Saturn: Interior and B-field
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No solid surface
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Radiates 2x energy emitted from Sun
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Rocky liquid core
metallic hydrogen
Atmosphere (top 1,000 km only)
Power source unknown – likely continued
gravitational contraction
B-field but 20x weaker than Jupiter
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Still strong enough to channel auroras
Saturnian Aurora
Credit: J. Trauger (JPL), NASA
APOD: 2005 February 19
Persistent Saturnian Auroras
Credit: J. Clarke (Boston U.) &
Z. Levay (STScI), ESA, NASA
APOD: 2005 February 22
A Hurricane Over the South Pole of Saturn
Credit: CICLOPS, JPL, ESA, NASA
APOD: 2006 November 13
A Mysterious Hexagonal Cloud System on Saturn
Credit: NASA/JPL, VIMS Team, University of Arizona
APOD: 2007 April 3
Neon Saturn
Credit: VIMS Team, U. Arizona, ESA, NASA
APOD: 2007 June 27
A Persistent Electrical Storm on Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2008 May 5
Moons
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Titan
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Phoebe
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Only Solar System moon with thick atmosphere
Rains methane
Possibly a captured comet
Dione
Enceladus
Mimas
Rhea
Hyperion
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Very low density – lots of empty caverns
Rotating Titan in Infrared Light
Credit: VIMS Team, U. Arizona, ESA, NASA
APOD: 2006 February 15
Methane Rain Possible on Titan
APOD: 2006 August 2
Descent Panorama of Saturn's Titan
Credit: ESA, NASA, Descent Imager/Spectral Radiometer Team (LPL)
APOD: 2006 May 8
Titan Landscape
Credit: ESA, NASA,
Descent Imager/Spectral Radiometer Team (LPL)
APOD: 2005 January 17
Huygens on Titan Illustrated
Illustration Credit: ESA
APOD: 2006 January 31
Possible Methane Lakes on Titan
Credit: Cassini Radar Mapper, JPL, ESA, NASA
APOD: 2006 July 31
Phoebe: Comet Moon of Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2006 February 12
Ancient Craters on Saturn's Rhea
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2006 May 30
A Great White Spot on Rhea
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2005 May 30
Enceladus and the Search for Water
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2006 March 10
Fountains Discovered on Saturn's Enceladus
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2005 December 5
Enceladus Creates Saturn's E Ring
Credit: CICLOPS, JPL, ESA, NASA
APOD: 2007 March 27
Bright Cliffs Across Saturn's Moon Dione
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2006 September 5
Unusual Cratering on Saturn's Dione
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2007 August 1
Saturn's Iapetus: Moon with a Strange Surface
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2005 February 1
Iapetus in Black and White
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2007 September 14
An Unusually Smooth Surface on Saturn's Telesto
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2006 February 22
Pandora: A Shepherd Moon of Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
APOD: 2005 November 23
Neptune
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Very similar to Uranus
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R=30 AU; P=165 years
Mostly Hydrogen, helium, etc.
Colder, more storms than Uranus
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Excuse me?
Similar size, mass, color, rings
Excuse me?
Great Dark Spot disappeared
Now the outermost Planet
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Further than Pluto from 1979-1999
Pluto now considered only a “dwarf planet”
Dark Spots on Neptune
Credit: Voyager 2 Team, NASA
APOD: 2001 August 21
Neptune's Great Dark Spot: Gone But Not Forgotten
Credit: Voyager Project, JPL, NASA
APOD: 2001 December 1
Two Hours Before Neptune
Credit: Voyager 2, NASA
APOD: 2002 September 22
Crescent Neptune and Triton
Credit: Voyager 2, NASA
APOD: 2006 June 18
Neptune’s Moon Triton
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Large like a Galilean Moon of Jupiter
70% rock, 30% water ice
Rotates retrograde (backwards)
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Probably captured from elsewhere
Might have ice-volcanoes
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Like Saturn’s Enceladus
Triton: Neptune's Largest Moon
Credit: Voyager 2, NASA
APOD: 1999 October 10
APOD: 2005 October 3
Saturn's Hyperion: A Moon with Odd Craters
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA