Transcript Powerpoint
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) Paper Discussion Class Project Midterm Final exam (tentative) 40 % 10 % 15 % 10% 25 % 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 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