DOCSLIB.ORG

Linking Asteroids and Meteorites Through Reflectance Spectroscopy

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Linking Asteroids and Meteorites Through Reflectance Spectroscopy Astronomy 101 The Solar System Tuesday, Thursday 2:30-3:45 pm Hasbrouck 20 Tom Burbine [email protected] Course • Course Website: – http://blogs.umass.edu/astron101-tburbine/ • Textbook: – Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. • You also will need a calculator. Office Hours • Mine • Tuesday, Thursday - 1:15-2:15pm • Lederle Graduate Research Tower C 632 • Neil • Tuesday, Thursday - 11 am-noon • Lederle Graduate Research Tower B 619-O Homework • We will use Spark • https://spark.oit.umass.edu/webct/logonDisplay.d owebct • Homework will be due approximately twice a week Class Averages • For people who took all 4 tests: • Class average is 81 • Grades range from a 98.5 to a 55.4 • Scores will go up when the lowest exam grade is dropped after the final • A (92.50 – 100) • A- (89.50 – 92.49) • B+ (87.50 – 89.49) • B (82.50 – 87.49) • B- (79.50 – 82.49) • C+ (77.50 – 79.49) • C (72.50 – 77.49) • C- (69.50 – 72.49) • D (59.50 – 69.49) • F (below 59.49) Final • Cumulative • Monday - 12/14 • 4:00 pm • Hasbrouck 20 • Review Session • Sunday -12/13 • 3:00 pm • Hasbrouck 134 Formulas you may need to know • p2 = a3 • F = GMm/r2 • F = ma • a = GM/r2 • Escape velocity = sqrt(2GM/r) • T (K) = T (oC) + 273.15 • c = f*λ • E = h*f • KE = 1/2mv2 • E = mc2 • Density = mass/volume • Volume = 4/3πr3 More Formulas • Power emitted per unit surface area = σT4 • λmax (nm) = (2,900,000 nm*K)/T • Apparent brightness = Luminosity 4π x (distance)2 Intelligent Life • Intelligent life that we can detect is usually defined as life that can build a radio telescope Radio • Transmitting information over radio waves is very cheap • uses equipment that is easy to build • has the information-carrying capacity necessary for the task • The information also travels at the speed of light. Fermi’s Paradox • Where are they? Fermi’s Paradox • Why have we not observed alien civilizations even though simple arguments would suggest that some of these civilizations ought to have spread throughout the galaxy by now? Reason for question • Straightforward calculations show that a technological race capable of interstellar travel at (a modest) one tenth the speed of light ought to be able to colonize the entire Galaxy within a period of one to 10 million years. Explanation • Interested in us but do not want us (yet) to be aware of their presence (sentinel hypothesis or zoo hypothesis) Explanation • Not interested in us because they are by nature xenophobic or not curious Explanation • Not interested in us because they are so much further ahead of us Explanation • Prone to annihilation before they achieve a significant level of interstellar colonization, because: (a) they self-destruct (b) are destroyed by external effects, such as: (i) the collision of an asteroid or comet with their home world (ii) a galaxy-wide sterilization phenomenon (e.g. a gamma-ray burster (iii) cultural or technological stagnation Explanation • Capable of only interplanetary or limited interstellar travel because of fundamental physical, biological, or economic restraints Fermi’s paradox • The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations. • http://en.wikipedia.org/wiki/Fermi_paradox Jupiter • Largest planet – Mass - 1.899×1027 kg (317.8 Earths) – Jupiter is 2.5 times more massive than all the other planets combined • Mean density - 1.326 g/cm3 • Equatorial diameter - 142,984 km (11.209 Earths) Probes to Jupiter • Pioneer 10 – 1973 • Pioneer 11 - 1974 • Voyager 1 – 1979 • Voyager 2 - 1979 • Ulysses - 1992 • Galileo – 1995 - Orbiter • Cassini - 2000 Jupiter • Jupiter's atmosphere is composed of ~81% hydrogen and ~18% helium. • Jupiter probably has a core of rocky material amounting to something like 10 to 15 Earth-masses. • Above the core lies the main bulk of the planet in the form of liquid metallic hydrogen. This exotic form of the most common of elements is possible only at pressures exceeding 4 million bars – 1 bar ≈ standard atmospheric pressure at sea level on Earth. • Jupiter is composed – relatively small rocky core – surrounded by metallic hydrogen – surrounded by liquid hydrogen – surrounded by gaseous hydrogen. Clouds • clouds of ammonia (NH3), methane (CH4), ammonia hydrosulfide (NH4HS) • zone for the light stripes • belt for the dark stripes • http://en.wikipedia.org/wiki/Cloud_pattern_on_Jupiter • The differences in colors are caused by slight differences in chemical composition and temperature • http://zebu.uoregon.edu/~imamura/121/lecture- 13/vjupitr2.mov Galileo Probe Great Red Spot • A particularly violent storm, about three times Earth's diameter, is known as the Great Red Spot, and has persisted through more than three centuries of human observation. • The spot rotates counterclockwise, once every 7 days. Jupiter’s Rings • Jupiter has a faint planetary ring system composed of smoke-like dust particles knocked from its moons by meteor impacts. Jupiter has four rings Voyager 1 and 2 • Voyager 2 launched first (1977) • Then Voyager 1 (1977) Grand Tour • Planetary Grand Tour was an ambitious plan to send unmanned probes to the outermost planets of the solar system. Conceived by Gary Flandro of the Jet Propulsion Laboratory, the Grand Tour would have exploited the alignment of Jupiter, Saturn, Uranus, Neptune and Pluto Voyager 2 • Went to Jupiter, Saturn, Uranus, and Neptune Voyager 1 • Went to Jupiter and Saturn Voyager Golden Record Pioneer 10 and 11 Plaques (1972) Saturn Saturn • Known since prehistoric times • Galileo was the first to observe it with a telescope in 1610 • In 1659, Christian Huygens correctly inferred the geometry of the rings • Saturn is the least dense of the planets; its density (0.7 g/cc) is less than that of water. Rings • Very thin • 250,000 km or more in diameter they are less than one kilometer thick • The ring particles seem to be composed primarily of water ice, but they may also include rocky particles with icy coatings. Roche Limit • Rings are either a satellite torn apart by tidal forces or material that was never allowed to condense into moons because of the tidal forces • http://csep10.phys.utk.edu/astr161/lect/saturn/rings.html Cassini-Huygens • Visited Saturn and Titan Uranus Uranus • Discovered by William Herschel in 1781 • In 1977, the first nine rings of Uranus were discovered Atmosphere • The atmosphere of Uranus is composed of 83% hydrogen, 15% helium, 2% methane and small amounts of acetylene and other hydrocarbons. • Methane in the upper atmosphere absorbs red light, giving Uranus its blue-green color. Unusual • Tipped on its side • Why? Probably • Due to a collision Uranus’ Satellites • Cordelia • Miranda • Ophelia • Ariel • Bianca • Umbriel • Cressida • Titania • Desdemona • Oberon • Juliet • 2001U3 • Portia • Caliban • Rosalind • Stephano • 2003U2 • Trinculo • Belinda • Sycorax • 1986U10 • 2003U3 • Puck • Prospero • 2003U1 • Setebos • 2002U2 • Instead of being named after people from classical mythology, Uranus' moons take their names from the writings of William Shakespeare and Alexander Pope. Neptune Neptune • After the discovery of Uranus, it was noticed that its orbit was not as it should be in accordance with Newton's laws. • It was therefore predicted that another more distant planet must be perturbing Uranus' orbit. • Neptune was first observed by Johan Galle and Heinrich d'Arrest on 1846 Sept 23 very near to the locations predicted from theoretical calculations based on the observed positions of Jupiter, Saturn, and Uranus. Galileo • Galileo's astronomical drawings show that he had first observed Neptune on December 27, 1612, and again on January 27, 1613; • on both occasions Galileo had mistaken Neptune for a fixed star • Neptune's blue color is largely the result of absorption of red light by methane in the atmosphere Great Dark Spot • Thought to be a hole Scooter Small dark spot Great Dark Spot has disappeared Neptune’s Rings Shoemaker-Levy 9 • Comet that hit Jupiter • Discovered in 1993 • Hit Jupiter in 1994 Roche Limit • The smallest distance at which a natural satellite can orbit a celestial body without being torn apart by the larger body's gravitational force. The distance depends on the densities of the two bodies and the orbit of the satellite. • If a planet and a satellite have identical densities, then the Roche limit is 2.446 times the radius of the planet. • Jupiter's moon Metis and Saturn's moon Pan are examples of natural satellites that survive despite being within their Roche limits Why is the Roche Limit important? • Comet Shoemaker-Levy 9's decaying orbit around Jupiter passed within its Roche limit in July, 1992, causing it to break into a number of smaller pieces. • All known planetary rings are located within the Roche limit • The first impact occurred at 20:15 UTC on July 16, 1994 • Fragment A of the nucleus slammed into Jupiter's southern hemisphere at a speed of about 60 km/s. • Instruments on Galileo detected a fireball which reached a peak temperature of about 24,000 K, compared to the typical Jovian cloudtop temperature of about 130 K, before expanding and cooling rapidly to about 1500 K after 40 s. Has this happened before? Ganymede Ganymede-Europa Satellites • Jupiter has 63 known satellites • The four large Galilean moons plus many more small ones some of which have not yet been named: Simon Marius (1573-1624) • In 1614, Marius published his work Mundus Iovialis describing how he had discovered Jupiter’s Moons some days before Galileo did • The names by which these satellites are known today (Io, Europa, Ganymede and Callisto) are those given them by Marius. • But untile the middle of the 20th century, these satellited were known as "Jupiter I," "Jupiter II," "Jupiter III," and "Jupiter IV" • Gan De, a Chinese astronomer, may have discovered the moons in 362 BC Galileo Galileo spacecraft • Launched in 1989 • It arrived at Jupiter on December 7, 1995 • On September 21, 2003, Galileo's mission ended by crashing into Jupiter's atmosphere to avoid any chance of it contaminating the Galilean moons with bacteria from Earth.
Load more

Recommended publications
  • Mission to Jupiter
    This book attempts to convey the creativity, Project A History of the Galileo Jupiter: To Mission The Galileo mission to Jupiter explored leadership, and vision that were necessary for the an exciting new frontier, had a major impact mission’s success. It is a book about dedicated people on planetary science, and provided invaluable and their scientific and engineering achievements. lessons for the design of spacecraft. This The Galileo mission faced many significant problems. mission amassed so many scientific firsts and Some of the most brilliant accomplishments and key discoveries that it can truly be called one of “work-arounds” of the Galileo staff occurred the most impressive feats of exploration of the precisely when these challenges arose. Throughout 20th century. In the words of John Casani, the the mission, engineers and scientists found ways to original project manager of the mission, “Galileo keep the spacecraft operational from a distance of was a way of demonstrating . just what U.S. nearly half a billion miles, enabling one of the most technology was capable of doing.” An engineer impressive voyages of scientific discovery. on the Galileo team expressed more personal * * * * * sentiments when she said, “I had never been a Michael Meltzer is an environmental part of something with such great scope . To scientist who has been writing about science know that the whole world was watching and and technology for nearly 30 years. His books hoping with us that this would work. We were and articles have investigated topics that include doing something for all mankind.” designing solar houses, preventing pollution in When Galileo lifted off from Kennedy electroplating shops, catching salmon with sonar and Space Center on 18 October 1989, it began an radar, and developing a sensor for examining Space interplanetary voyage that took it to Venus, to Michael Meltzer Michael Shuttle engines.
    [Show full text]
  • JUICE Red Book
    ESA/SRE(2014)1 September 2014 JUICE JUpiter ICy moons Explorer Exploring the emergence of habitable worlds around gas giants Definition Study Report European Space Agency 1 This page left intentionally blank 2 Mission Description Jupiter Icy Moons Explorer Key science goals The emergence of habitable worlds around gas giants Characterise Ganymede, Europa and Callisto as planetary objects and potential habitats Explore the Jupiter system as an archetype for gas giants Payload Ten instruments Laser Altimeter Radio Science Experiment Ice Penetrating Radar Visible-Infrared Hyperspectral Imaging Spectrometer Ultraviolet Imaging Spectrograph Imaging System Magnetometer Particle Package Submillimetre Wave Instrument Radio and Plasma Wave Instrument Overall mission profile 06/2022 - Launch by Ariane-5 ECA + EVEE Cruise 01/2030 - Jupiter orbit insertion Jupiter tour Transfer to Callisto (11 months) Europa phase: 2 Europa and 3 Callisto flybys (1 month) Jupiter High Latitude Phase: 9 Callisto flybys (9 months) Transfer to Ganymede (11 months) 09/2032 – Ganymede orbit insertion Ganymede tour Elliptical and high altitude circular phases (5 months) Low altitude (500 km) circular orbit (4 months) 06/2033 – End of nominal mission Spacecraft 3-axis stabilised Power: solar panels: ~900 W HGA: ~3 m, body fixed X and Ka bands Downlink ≥ 1.4 Gbit/day High Δv capability (2700 m/s) Radiation tolerance: 50 krad at equipment level Dry mass: ~1800 kg Ground TM stations ESTRAC network Key mission drivers Radiation tolerance and technology Power budget and solar arrays challenges Mass budget Responsibilities ESA: manufacturing, launch, operations of the spacecraft and data archiving PI Teams: science payload provision, operations, and data analysis 3 Foreword The JUICE (JUpiter ICy moon Explorer) mission, selected by ESA in May 2012 to be the first large mission within the Cosmic Vision Program 2015–2025, will provide the most comprehensive exploration to date of the Jovian system in all its complexity, with particular emphasis on Ganymede as a planetary body and potential habitat.
    [Show full text]
  • High-Resolution Mosaics of the Galilean Satellites from Galileo SSI
    Lunar and Planetary Science XXIX 1833.pdf High-Resolution Mosaics of the Galilean Satellites from Galileo SSI. M. Milazzo, A. McEwen, C. B. Phillips, N. Dieter, J. Plassmann. Planetary Image Research Laboratory, LPL, University of Arizona, Tucson, AZ 85721; [email protected] The Galileo Spacecraft began mapping the Jovian orthographic projection centered at the latitude and system in June 1996. Twelve orbits of Jupiter and more longitude coordinates of the sub-spacecraft point to than 1000 images later, the Solid State Imager (SSI) is still preserve their perspective. Depending on the photometric collecting images, most far superior in resolution to geometry and scale, it may be necessary to apply a anything collected by the Voyager spacecraft. The data photometric normalization to the images. Next, the collected includes: low to medium resolution color data, individual frames are mosaicked together, and mosaicked medium resolution data to fill gaps in Voyager coverage, and onto a portion of the base map for regional context. Once very high-resolution data over selected areas. We have the mosaic is finished, it is checked to make sure that the tie been systematically processing the SSI images of the and match points were correct, and that the frames mesh. Galilean satellites to produce high-resolution mosaics and to We produce 3 final products: (i) an SSI-only mosaic, (ii) SSI place them into the regional context provided by medium- images mosaicked onto regional context, and (iii) the resolution mosaics from Voyager and/or Galileo. addition of a latitude-longitude grid to the context mosaic. Production of medium-resolution global mosaics is The purpose of this poster is to show the mosa- described in a companion abstract [1].
    [Show full text]
  • Appendix Contains a Timeline, Galileo Mission Overview (June 1996–December 1997), and a Set of Quick–Look Orbit Facts Sheets
    A P P E N D I X This appendix contains a timeline, Galileo Mission Overview (June 1996–December 1997), and a set of Quick–Look Orbit Facts sheets. The essentials of each orbit are listed. We have provided them as a handy reference while the orbiter’s tour progresses in the months to come. Appendix • Page A-1 Project Galileo Quick-Look Orbit Facts Appendix • Page A- 5 PROJECT GALILEO QUICK-LOOK ORBIT FACTS Fact Sheet Guide Title Quick Facts Indicates the target satellite and the number of the This section provides a summary listing of the orbit in the satellite tour. In this example, Ganymede is characteristics of the target satellite encounter as well the target satellite on the first orbit of the orbital tour. as the Jupiter encounter. PROJECT GALILEO QUICK-LOOK ORBIT FACTS PROJECT GALILEO QUICK-LOOK ORBIT FACTS Ganymede - Orbit 1 Ganymede - Orbit 1 Encounter Trajectory Quick Facts Ganymede Flyby Geometry +30 min Ganymede Encounter Earth Sun 27 June 1996 Ganymede C/A +15 min 06:29 UTC Ganymede C/A Altitude: 844 km Jupiter 6/27 6/26 133 times closer than VGR1 70 times closer than VGR2 Earth Speed: 7.8 km/s 0W -15 min Sun Jupiter C/A 6/28 Latitude: 30 deg N Longitude: 112 deg W 270W -30 min Perijove Io 28 June 1996 00:31 UTC Europa Jupiter Range: 11.0 Rj Time Ordered Listing Ganymede 6/29 Earth Range: 4.2 AU EVENT TIME (PDT-SCET) EVENT (continued) TIME (PDT-SCET) OWLT: 35 min Start Encounter 23 June 96 09:00 Europa C/A (156000 km) 18:22 Callisto Start Ganymede-1 real-time survey (F&P) 09:02 Europa global observation (NIMS/SSI) 18:43
    [Show full text]
  • The Other Side
    Just how did we get there? and space; like Tarzan swinging from technology, and human expertise As the outer planets plod through vine to vine through the jungle, missing to catch up. the frozen void, once every 175 years a transition by even the smallest of JPL formally proposed the Grand they line up in such a way that Jupiter’s margins would spell disaster. A few Tour in 1970, with Harris M. “Bud” gravity can be used to fing a properly months and several reams of graph Schurmeier (BS ’45, MS ’48, ENG aimed spacecraft on toward Saturn, paper later, Flandro had worked out ’49) as the project manager. This was and thence to Uranus and Neptune. In hundreds of itineraries—some reaching an A-team effort: Schurmeier had just THE the spring of 1965, Caltech aeronautics all the way to then-planet Pluto—for presided over the Mariner 6 and 7 grad student Gary Flandro (MS ’60, the upcoming launch window. His fybys of Mars, and his collaborators PhD ’67) was working part-time up boss, Elliott “Joe” Cutting, booked included JPL’s planetary program at JPL analyzing so-called gravity- him a meeting with the chief of JPL’s director, Robert Parks (BS ’44), and its assist trajectories when he realized that advanced technical studies offce, spacecraft systems manager, Raymond OTHER such a four-for-one alignment would aeronautics professor Homer Stewart Heacock (BS ’52, MS ’53). It was also occur between 1976 and 1979; (PhD ’40). Stewart embraced the idea, a gold-plated Cadillac of a mission—a intrigued by the possibilities, he set christening it the Grand Tour.
    [Show full text]
  • The Global Colors of Ganymede As Seen by Galileo Ssi
    Lunar and Planetary Science XXX 1822.pdf THE GLOBAL COLORS OF GANYMEDE AS SEEN BY GALILEO SSI. T. Denk1, K.K. Khurana2, R.T. Pappalardo3, G. Neukum1, J.W. Head3, T.V. Rosanova4, and the Galileo SSI Team, 1DLR, Institute of Planetary Exploration, 12484 Berlin, Germany, e-mail: [email protected], 2UCLA, Los Angeles, CA, 3Brown University, Providence, RI, 4USGS, Flagstaff, AZ. Ganymede, as observed by the Galileo SSI Dark vs. bright and polar terrain. The bright camera, shows a banded, latitude-dependent color ("sulci") and dark ("regio") areas as well as the polar structure which is partly independent of geologic caps are the most obvious surface features on Ganyme- units. A correlation of the surface color with the de when seen at global scale from large distances. The magnetic field of Ganymede is reported, with areas albedo of the polar caps on the leading side is highest, exposed to the charged particles coming from the of the "regio" areas lowest, and of the "sulci" areas in Jovian environment often being redder than shielded between. (The polar caps of the trailing side will be terrain. The northern polar cap can be subdivided discussed below.) The bright polar caps are probably into a whitish area on the pole and the leading side, caused by water frost (e.g., Smith et al. 1981, Hillier and a darker, reddish area on the trailing side. The frost of the south-polar cap appears less opaque than in the north. The spectra of the dark "regio" areas are redder at the long SSI wavelength range than those of the brighter "sulci" terrains, but not significantly different at short SSI wavelengths.
    [Show full text]
  • NASA PAST and Future: a Personal Memoir
    STORY | ASK MAGAZINE | 25 NASA Past anD FUTURE: A PER sonaL MEmoIR BY Ken Randle When I was working for the Sperry Corporation in the sixties, we submitted a proposal to the Jet Propulsion Laboratory (JPL) to provide support for their unmanned space exploration programs. Our proposal won and, in July 1966, I took a team of twenty-three engineers to JPL. I had two responsibilities: manage the team and provide the configuration design of spacecraft for the Future Projects Study team. Mariner 10’s first image of Mercury, Photo Credit: NASA acquired on March 24, 1974. 26 | ASK MAGAZINE Exploring the Solar System For this discovery, Flandro received an award from the British T he Fut u re Projec t s St udy te a m, u nder JPL’s d irec t ion, per formed Interplanetary Society. The grand tour missions would require four six-month feasibility studies for NASA’s consideration. Two an entirely new kind of spacecraft, a design with capabilities far of them became successful missions—a pretty good record. beyond those of the simple machines that had reached the moon, The first study was for a mission to Venus with the release of Venus, and Mars. At the time, Voyager was the most complex a capsule to the surface before going on to a flyby of Mercury. unmanned machine ever designed. There had to be a boom for This became the Mariner 10 mission, the first mission to use the radioisotope thermoelectric generator, another boom for the the gravity assist of one planet to reach another planet.
    [Show full text]
  • Voyager Issue 2 Spring 2018
    ISSUE The University of Tennessee Space Institute’s 02 May 2018 Voyager Featured in this Highlights Issue A Message from the Executive Director, 2018 Black History Month program Dr. Mark Whorton Recent & Spring is now in full swing at the UT Space Institute and Wu’s Student Upcoming great things are happening. Thanks to Meghan Morris Competition Events for a great job in pulling together our UTSI Newsletter – The UTSI Voyager! We are especially excited about our newsletter title this month because it directly reflects on Astronaut Seddon Accolades our friend and colleague, Dr. Gary Flandro. Dr. Flandro is being honored in May as a Distinguished Alumnus of Caltech for his stellar achievement in conceiving the Students Dominate Featured Grand Tour of outer planets using gravitational assists in AIAA Student Department the Voyager Missions. Please congratulate Dr. Flandro Conference for this well-deserved, high honor. You will also read in the following pages about other great work by our team Welcomes as well as upcoming events. We are excited that our Kraft - Guest Speaker Chancellor, Dr. Beverly Davenport, is bringing her cabinet for AIAA Greater to visit our campus on June 4. Let’s get ready for a great Huntsville Section Student Clubs visit to show that UTSI is the place to be. Schmisseur lead of $9.8 million dollar contract UTSI’s newest family Marvin Look for in each issue! member, Tonya Travis Recent Events at UTSI Dr. Sidney A. 3rd Annual Wu Student Former NASA Astronaut, Rhea McPhee, speaker for Presentation Competition rd Seddon, M.D. 23 Annual African March 28, 2018 at UTSI American History Twelve students competed in the student competition.
    [Show full text]
  • Radar Imaging of Solar System Ices
    RADAR IMAGING OF SOLAR SYSTEM ICES A DISSERTATION SUBMITTED TO THE DEPARTMENT OF ELECTRICAL ENGINEERING AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY Leif J. Harcke May 2005 © Copyright by Leif J. Harcke 2005 All Rights Reserved ii iv Abstract We map the planet Mercury and Jupiter’s moons Ganymede and Callisto using Earth-based radar telescopes and find that all bodies have regions exhibiting high, depolarized radar backscatter and polarization inversion (µc > 1). Both characteristics suggest volume scat- tering from water ice or similar cold-trapped volatiles. Synthetic aperture radar mapping of Mercury’s north and south polar regions at fine (6 km) resolution at 3.5 cm wavelength corroborates the results of previous 13 cm investigations of enhanced backscatter and po- larization inversion (0:9 µc 1:3) from areas on the floors of craters at high latitudes, ≤ ≤ where Mercury’s near-zero obliquity results in permanent Sun shadows. Co-registration with Mariner 10 optical images demonstrates that this enhanced scattering cannot be caused by simple double-bounce geometries, since the bright, reflective regions do not appear on the radar-facing wall but, instead, in shadowed regions not directly aligned with the radar look direction. A simple scattering model accounts for exponential, wavelength-dependent attenuation through a protective regolith layer. Thermal models require the existence of this layer to protect ice deposits in craters at other than high polar latitudes. The additional attenuation (factor 1:64 15%) of the 3.5 cm wavelength data from these experiments over previous 13 cm radar observations supports multiple interpretations of layer thickness, ranging from 0 11 to 35 15 cm, depending on the assumed scattering law exponent n.
    [Show full text]
  • Challenging the Paradigm: the Legacy of Galileo Symposium
    Challenging the Paradigm: The Legacy of Galileo Symposium November 19, 2009 California Institute of Technology Pasadena, California Proceedings of the 2009 Symposium and Public Lecture Challenging the Paradigm: The Legacy of Galileo NOVEMBER 19, 2009 CAHILL BUILDING - HAMEETMAN AUDITORIUM CALIFORNIA INSTITUTE OF TECHNOLOGY PASADENA, CALIFORNIA, USA © 2011 W. M. KECK INSTITUTE FOR SPACE STUDIES, ISBN-13: 978-1-60049-005-07 CALIFORNIA INSTITUTE OF TECHNOLOGY ISBN-10: 1-60049-005-0 Sponsored by The W.M. Keck Institute for Space Studies Supported by The Italian Consulate – Los Angeles The Italian Cultural Institute – Los Angeles Italian Scientists and Scholars in North America Foundation The Planetary Society Organizing Committee Dr. Cinzia Zuffada – Jet Propulsion Laboratory (Chair) Professor Mike Brown – California Institute of Technology (Co-Chair) Professor Giorgio Einaudi – Università di Pisa Dr. Rosaly Lopes – Jet Propulsion Laboratory Professor Jonathan Lunine - University of Arizona Dr. Marco Velli – Jet Propulsion Laboratory Table of Contents Introduction……………………………………………………………………………….. 1 Galileo's New Paradigm: The Ultimate Inconvenient Truth…………………………... 3 Professor Alberto Righini University of Florence, Italy Galileo and His Times…………………………………………………………………….. 11 Professor George V. Coyne, S.J. Vatican Observatory The Galileo Mission: Exploring the Jovian System…………………………………….. 19 Dr. Torrence V. Johnson Jet Propulsion Laboratory, California Institute of Technology What We Don't Know About Europa……………………………………………………. 33 Dr. Robert T. Pappalardo Jet Propulsion Laboratory, California Institute of Technology The Saturn System as Seen from the Cassini Mission…………………………………. 55 Dr. Angioletta Coradini IFSI – Istituto di Fisica dello Spazio Interplanetario dell’INAF - Roma Solar Activity: From Galileo's Sunspots to the Heliosphere………………………….. 67 Professor Eugene N. Parker University of Chicago From Galileo to Hubble and Beyond - The Contributions and Future of the Telescope: The Galactic Perspective…………………………………………………….
    [Show full text]
  • Beyond the Heliopause
    BOOKS & ARTS COMMENT SPACE SCIENCE Beyond the heliopause Roger D. Launius savours a masterful account, by a veteran of interplanetary space science, of the Voyager probes’ mission to the giant planets. spacecraft for an extended mission. Voyager was downgraded to a Jupiter–Saturn fly-by, but engineers designed as much longevity into the probes as the US$875-million budget would allow. NASA launched Voyager 2 on 20 August 1977, and Voyager 1 followed on a faster, shorter trajectory on 5 September. Bell, who hung out with the science team as an undergraduate at the California Insti- tute of Technology in Pasadena, describes how the craft achieved their objectives — and then some. Voyager 1 was, for example, pro- grammed for a close encounter with Saturn’s moon Titan, during which it revealed a com- plex world with an atmosphere, thick clouds and water ice. It showed that Titan was ripe for scientific investigation, paving the way for the sustained investigations of the Huygens– Cassini mission at the dawn of this century. But this fly-by deflected Voyager 1 out of the Solar System’s elliptical plane; unable to con- tinue on to Uranus and Neptune, the craft’s planetary mission ended. Voyager 2 continued on to the two outer­ most giant planets. Bell reports how, as the probes flew, controllers constantly repro- grammed the on-board computers, which had only about 5,000 words’ worth of mem- ory each, to take advantage of scientific opportunities. Successfully capturing data was hugely taxing, but mission engineers and scientists made it work. The probes explored the giant planets’ systems of rings and magnetic fields, find- NASA/SPL Jupiter’s Great Red Spot, a massive stable storm photographed by Voyager 2 in 1979.
    [Show full text]
  • Modern Mars' Geomorphological Activity
    Title: Modern Mars’ geomorphological activity, driven by wind, frost, and gravity Serina Diniega, Ali Bramson, Bonnie Buratti, Peter Buhler, Devon Burr, Matthew Chojnacki, Susan Conway, Colin Dundas, Candice Hansen, Alfred Mcewen, et al. To cite this version: Serina Diniega, Ali Bramson, Bonnie Buratti, Peter Buhler, Devon Burr, et al.. Title: Modern Mars’ geomorphological activity, driven by wind, frost, and gravity. Geomorphology, Elsevier, 2021, 380, pp.107627. 10.1016/j.geomorph.2021.107627. hal-03186543 HAL Id: hal-03186543 https://hal.archives-ouvertes.fr/hal-03186543 Submitted on 31 Mar 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 1 Title: Modern Mars’ geomorphological activity, driven by wind, frost, and gravity 2 3 Authors: Serina Diniega1,*, Ali M. Bramson2, Bonnie Buratti1, Peter Buhler3, Devon M. Burr4, 4 Matthew Chojnacki3, Susan J. Conway5, Colin M. Dundas6, Candice J. Hansen3, Alfred S. 5 McEwen7, Mathieu G. A. Lapôtre8, Joseph Levy9, Lauren Mc Keown10, Sylvain Piqueux1, 6 Ganna Portyankina11, Christy Swann12, Timothy N. Titus6,
    [Show full text]