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: 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

• 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