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EART 160: Planetary Science
These and all images courtesy NASA / JPL / GSFC unless otherwise noted
Some Terms
• Planet– Orbits a star, but isn’t one (no fusion)– Spherical shape (self-gravity, R > 1000 km?)– Cleared its orbit
• Dwarf Planet– Planet that hasn’t cleared its orbit
• Small solar-system body– Anything else that orbits the sun– Asteroids, Comets, Trans-Neptunian Object
(TNO)
• Planetary body– Planets and smaller objects
• Satellite or Moon– Orbits a larger planetary body
• Planetesimal– Small planetary body (< 1000 km)– Early solar system– Building block of planets
• World– Planet, Dwarf Planet, Large Satellite– Planet-like by “truthiness”
What is the class about?
• Meeting of Astronomy, Geology, and Physics
• How did the planets form?• What are they made of?• What’s happening to them?• How do we know all this?
• Foundation class for Planetary Sciences track– Eart 162: Planetary Interiors – Eart 163: Planetary Surfaces – Eart 164: Planetary Atmospheres
Contact Info
• My Name: James Roberts
• E-mail: [email protected]
• Phone: 9-3200
• Office: E&MS A200
• Office Hours: Monday 2 – 3 Thursday 11 – 12 Or by appointment
Website
• WebCT: http://ic.ucsc.edu/webct/– Login with your UCSC username and password– Uses Javascript– May need to add yourself here:
https://ic.ucsc.edu/services/learning_management_system/create_account.php – Please let me know if there’s a problem!
• Backup at http://es.ucsc.edu/~jhr/EART160– Won’t have copyrighted material
Books
• Reference, not a textbook• Beatty, Petersen, Chaiken.
The New Solar System, 4th ed.– Campus bookstore should
have this (~$70)– On reserve in Science Library– Preview available at
books.google.com
• Also on reserve:– Faure and Mensing,
Introduction to Planetary Science– Hartmann, Moons and Planets, 4th ed.
• Prerequisites:– Single-variable calculus
(e.g. Math 11B or 19B)– Introductory Physics
(e.g. Phys 5A or 6A)
• Course Philosophy– Ask questions!– Grasp concepts
before mathematics– Be critical– Connect theory to
observation
“How is astronomy different from astrology?”
“Lots and lots of math.”
-- Wiley, Non Sequitur
Homeworks
• Conceptual Questions (explain in words)
• Problems (set up and solve)
• Due each Friday
• Collaborate, don’t copy
• See me if you get stuck– It should not take you more
than an hour per problem!
Paper Discussion
• Each Friday we’ll have an in-class discussions of 1 or 2 short journal articles
• Everyone reads the paper before class– Try to understand as much as you can
• One of you gives a 5-minute summary to the class– Everybody does this once
• Discuss. What did you learn? What doesn’t make sense?
Class Project
• Pick a topic in Planetary Science • Come see me• Read up on it• Write a short paper, synthesizing your findings
and summarizing the topic• Due the last day of class: 17 March 2008• Alternately, conduct an original research project• Details will be provided in the next week or two.
Exams
• Midterm: 08 February 2008
• Final: 19 March 2008
• Questions will be similar to homeworks, but in a closed environment
• Closed-book, but you can use a single page of notes
• You must pass the final to pass the class!
Your Grade
• Weekly Homework (7 total) 40 %
• Paper Discussion 10 %
• Class Project 15 %
• Midterm 10%
• Final exam 25 %
(tentative)
Topics
• Celestial Mechanics• Solar system origin and evolution• Surfaces and interiors• Atmospheres• Rings, moons, and tides• Comets and asteroids• Space Exploration: Missions,
Astrobiology, Extrasolar Planets
• Proposed schedule is not inflexible
At last!
• Any questions on administrivia?
• Now let’s do something interesting!
• Please interrupt me at any time with questions.
Terrestrial Planets
Rock, Metal, Small amount of volatiles1000 km < R < 10000 km ?a < 5 AU (1 AU = 1.5×108 km)
Mercury
Venus Earth
The Moon
Mars
Io
Jovian PlanetsIce GiantsMostly Ice, rocky cores,
thick atmospheresR ~ 25,000 kma > 19 AU
Gas GiantsMostly Gas, Ice/Rock CoresR > 60,000 kma ~ 5-10 AU
Jupiter
Saturn
Uranus
Neptune
All have ringsMany moons
Icy Satellites
Europa
Ganymede Callisto
TitanTriton
Icy surfaceMay have rocky coreMay be rock and ice mixedMay have subsurface oceanR < 3000 kmOrbit Jovian planets
Trans-Neptunian Objects
Similar to Icy satellitesDo not orbit planetsa > 30 AU
AsteroidsItokawa
Hayabusa Flyby/”Landing” 2005Sample Return 2010
Ceres
Dawn: Flybys 2011-2015
Vesta
Made of Rock
Most in Asteroid belt (a = 2.5 – 3 AU)
MonolithicRubble Pile
Comets
Hyakutake, 1995
Deep Impact: Flyby/Impactor 1995
Tempel 1
Ice, some rockExtremely eccentric orbitsR < 50 kmKuiper Belt: a = 30 – 55 AUOort Cloud: a = 55 AU – 50,000 AU
“Comets. The icebergs of the sky.”-- Billy West as Zapp Brannigan, Futurama
A sense of scale
6371 km
1737 km
But how far apart are they?
a = 3.84×105 km = 60 R
71,500 km
696,00 km
487 km
500 km
Inner Solar System Outer Planets TNOs
12 AU 100 AU
1000 AU20,000 AU
1 light-year
“Space. It seems to go on and on forever. And then you get to the end and the gorillastarts throwing barrels at you.”
-- Billy West as Philip Fry, Futurama
Neat stuff in the Solar System
Lunar Craters
Olympus Mons
Shield volcano27 km high600 km across
Valles Marineris
Large-scale Fracture4000 km long7 km deep
Image Courtesy Malin Space Science Systems
Valley Networks
Clouds on Jupiter
Cassini
Tvashtar on Io
New Horizons
The lavas of violent Io,Though they may look like pico de gallo,
Erupt and then rainOn the sulfurous plain
Looking nothing at all like Ohio.
Saturn’s Rings
Spokes
Radio ImageColors represent particle size
Enceladus
Tiger-stripesS. Polar Plume
There once was a moon called EnceladusWhose tiger-stripes have cast a spell at us.
The south polar plumeLike an icy mushroom
Has poked its way through the ice shell at us
Titan
Thick Haze
Surface ImageHuygens Probe
Radar Map, Cassini
Mimas and Iapetus
“That’s no moon … it’s a space station!”-- Alec Guiness as Obi-Wan Kenobi, Star Wars
Herschel
Ridge
AlbedoContrast
Iapetus hasA great ridge ‘round the middle.
What is up with that?
Extrasolar Planets
Charbonneau et al., 2000
Image Courtesy ESA/Hubble
HD 209458b
More than 270 detected so far!Many are “Hot Jupiters”
Spacecraft
MESSENGER mission to Mecury
1st flyby on Monday!
Research Opportunities
• Programs for planetary research, especially during the summer
• Usually Paid!
• Check class website for listings
• Deadlines are soon – apply today!
Earth
Saturn eclipsing SunCassini Image
The Sun
Mercury
MissionsMariner 10 Flybys 1974-1975
MeSSEnGeR Launched 2004
Flyby 14 Jan 2008
Orbit 2011
Very dense
Large Iron Core
Not fully mapped
Caloris Basin3:2 Spin-Orbit Resonance
Venus
MissionsMariner 2 Flyby 1962
Venera 4 Probe 1967
Mariner 5 Flyby 1967
Venera 5, 6 Probes 1969
Venera 7-14 Landers 1970-1981
Pioneer Orbiter, Probes 1978-1992
Venera 15, 16 Orbiters 1983
Vega 1, 2 Probes, Landers 1985
Magellan Orbiter 1990-1994
Venus Express Orbiter 2006 – presentClouds of CO2 and H2SO4
90 bars pressure at surface
450 K surface temperature
Magellan RADAR Map
Aphrodite Terra
Ishtar Terra
Earth
Liquid WaterLifePlate TectonicsLarge MoonMagnetic Field
The Moon
Near SideFar Side
Maria (lava flows)
Terrae (cratered highlands)
Rotates synchronously
Luna 1-3 Flybys 1959
Pioneer 4 Flyby 1959
Ranger 4, 7-9 Impactors, 1962-1964
Zond 1-7 Flybys, 1965-1970
Luna 9-24 Landers, Orbiters 1965-1976
Surveyor 1-7 Landers, 1966-1968
Lunar Orbiter 1-5 Orbiters, 1966-1968
Explorer 35 Orbiter 1967-1973
Apollo 8, 10, 13 Manned Orbiters 1968-1970
Apollo 11, 12, 14-17 Manned Landers 1969-1972
Lunakhod 1, 2 Rovers 1970-1973
Hiten 1990-1993
Smart 1 1993-1996
Clementine Orbiter 1994
Lunar Prospector Orbiter 1998-1999
Chang’e Orbiter 2007
Chandrayaan Orbiter 09 April 2008
Lunar Reconnaisance Orbiter Orbiter 28 Oct 2008
MarsMost Earth-like planetPolar ice capsVolcanoesEvidence for past liquid water
Mariner 4, 6, 7 Flybys 1965-1969
Mariner 9 Orbiter 1971
Mars 2, 3 Orbiters 1971-1972
Viking 1, 2 Orbiters/Landers 1976-1980
Mars Global Surveyor Orbiter 1997-2006
Mars Pathfinder Lander/Rover 1997-2003
Mars Odyssey Orbiter 2001 - present
Mars Express Orbiter 2003 - present
Spirit / Orbiter Rovers 2004 – present
Mars Reconaissance Orbiter Orbiter 2006 – present
Phoenix Lander 25 May 2008
Mars Missions
GaspraMathilde
Ida
Dactyl
Eros
NEAR Shoemaker: Flyby 1997Orbiter/Lander 2000-2001
Galileo: Flybys 19911993
Jupiter
Pioneer 10, 11 Flybys 1973-1974
Voyager 1, 2 Flybys 1979
Galileo Orbiter 1995-2003
Cassini Flyby 2000
New Horizons Flyby 2007
Galilean Moons
Tvashtar Plume on Io
Conamara Chaos on Europa
Saturn
Pioneer 11 Flyby 1979
Voyager 1, 2 Flybys 1980-1981
Cassini Orbiter 2004-present
Huygens Titan Probe/Lander 2004
Uranus
Tilted on its side!Ring systemMethane Clouds
Voyager 2 Flyby 1986
Five medium-sized moons
Neptune
Voyager 2 Flyby 1989
Great Dark Spot
Triton
Captured Asteroid?Retrograde OrbitNitrogen Geysers