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
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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
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My Name: James Roberts
E-mail:
jhr@ucsc.edu
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
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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
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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
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Weekly Homework (7 total)
Paper Discussion
Class Project
Midterm
Final exam
(tentative)
40 %
10 %
15 %
10%
25 %
Topics
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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
Mercury
Mars
Venus
Rock, Metal, Small amount of volatiles
1000 km < R < 10000 km ?
a < 5 AU
(1 AU = 1.5×108 km)
Earth
The Moon
Io
Jovian Planets
Ice Giants
Mostly Ice, rocky cores,
thick atmospheres
R ~ 25,000 km
a > 19 AU
Neptune
All have rings
Many moons
Uranus
Saturn
Gas Giants
Mostly Gas, Ice/Rock Cores
R > 60,000 km
a ~ 5-10 AU
Jupiter
Icy Satellites
Europa
Ganymede
Triton
Titan
Callisto
Icy surface
May have rocky core
May be rock and ice mixed
May have subsurface ocean
R < 3000 km
Orbit Jovian planets
Trans-Neptunian Objects
Similar to Icy satellites
Do not orbit planets
a > 30 AU
Asteroids
Itokawa
Ceres
Monolithic
Rubble Pile
Dawn: Flybys 2011-2015
Hayabusa Flyby/”Landing” 2005
Sample Return 2010
Made of Rock
Most in Asteroid belt (a = 2.5 – 3 AU)
Vesta
Comets
Hyakutake, 1995
“Comets. The icebergs of the sky.”
-- Billy West as Zapp
Brannigan, Futurama
Tempel 1
Ice, some rock
Extremely eccentric orbits
R < 50 km
Kuiper Belt: a = 30 – 55 AU
Oort Cloud: a = 55 AU – 50,000 AU
Deep Impact: Flyby/Impactor 1995
A sense of scale
But how far apart are they?
1737 km
6371 km
a = 3.84×105 km = 60 R
71,500 km
487 km
500 km
696,00 km
Inner Solar System
Outer Planets
TNOs
12 AU
20,000 AU
100 AU
1000 AU
1 light-year
“Space. It seems to go on and on forever. And then you get to the end and the gorilla
starts throwing barrels at you.”
-- Billy West as Philip Fry, Futurama
Neat stuff in the Solar System
Lunar Craters
Olympus Mons
Valles Marineris
Shield volcano
27 km high
600 km across
Large-scale Fracture
4000 km long
7 km deep
Valley Networks
Image Courtesy Malin Space Science Systems
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 rain
On the sulfurous plain
Looking nothing at all like Ohio.
Saturn’s Rings
Spokes
Radio Image
Colors represent particle size
Enceladus
S. Polar Plume
Tiger-stripes
There once was a moon called Enceladus
Whose tiger-stripes have cast a spell at us.
The south polar plume
Like an icy mushroom
Has poked its way through the ice shell at us
Titan
Thick Haze
Radar Map, Cassini
Surface Image
Huygens Probe
Mimas and Iapetus
Herschel
Albedo
Contrast
Ridge
“That’s no moon … it’s a space station!”
-- Alec Guiness as Obi-Wan
Kenobi, Star Wars
Iapetus has
A great ridge ‘round the middle.
What is up with that?
Extrasolar Planets
HD 209458b
Image Courtesy
ESA/Hubble
More than 270 detected so far!
Many are “Hot Jupiters”
Charbonneau et al., 2000
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 Sun
Cassini Image
The Sun
Mercury
Very dense
Large Iron Core
Not fully mapped
Missions
Mariner 10
Flybys 1974-1975
MeSSEnGeR
Launched 2004
Flyby 14 Jan 2008
Orbit 2011
3:2 Spin-Orbit Resonance
Caloris Basin
Venus
Missions
Clouds of CO2 and H2SO4
90 bars pressure at surface
450 K surface temperature
Mariner 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 – present
Magellan RADAR Map
Aphrodite Terra
Ishtar Terra
Earth
Liquid Water
Life
Plate Tectonics
Large Moon
Magnetic Field
The Moon
Maria (lava flows)
Near Side
Rotates synchronously
Far Side
Terrae (cratered highlands)
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
Mars
Most Earth-like planet
Polar ice caps
Volcanoes
Evidence for past liquid water
Mars Missions
Mariner 4, 6, 7
Mariner 9
Mars 2, 3
Viking 1, 2
Flybys 1965-1969
Orbiter 1971
Orbiters 1971-1972
Orbiters/Landers 1976-1980
Mars Global Surveyor
Mars Pathfinder
Mars Odyssey
Orbiter 1997-2006
Lander/Rover 1997-2003
Orbiter 2001 - present
Mars Express
Orbiter 2003 - present
Spirit / Orbiter
Rovers 2004 – present
Mars Reconaissance Orbiter Orbiter 2006 – present
Phoenix
Lander 25 May 2008
Mathilde
NEAR Shoemaker: Flyby 1997
Orbiter/Lander 2000-2001
Gaspra
Galileo: Flybys
1991
1993
Ida
Eros
Dactyl
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 system
Methane Clouds
Voyager 2
Flyby 1986
Five medium-sized moons
Neptune
Great Dark Spot
Voyager 2
Flyby 1989
Triton
Captured Asteroid?
Retrograde Orbit
Nitrogen Geysers