What is the Meaning of This? Claudia Alexander Over a decade of exploration... Discovery of an ocean: Priceless Major Findings: • An ocean under the surface of Europa. • First ever successful probe of a gas giant atmosphere. • An icy satellite capable of gggenerating its own magnetosphere (Ganymede). • Characterization of the thin exospheres of icy satellites. • Sufficient detail of Io’s volcanism to call it a window into Earth’s past. • Detailed sampling of the Io plasma environment and its intricate connection to the dynamics of the magnetosphere. • Complete understanding of the formation of the Jovian ring. • High resolution sampling of a rarely Project Inception—November 19, 1977 visited region: the Jovian radiation belts LhdItltCiLaunch and Interplanetary Cruise—Oc t. 18, 1989 - Dec. 5, 1995 Galileo Prime Mission—Dec. 5, 1995 - Dec. 15, 1997 Galileo Europa Mission (GEM)—Dec. 15, 1997 - Jan. 1, 2000 • Discovery of an asteroid with its own Galileo Millennium Mission (GMM)—Jan. 1, 2000 - Sept. 21, 2003 moon 10/21/03 Galileo End of Mission Summary ‐cja‐ 2 Claudia with GLL Comet Nevski‐Novichonok (ISON) as it may appear at sunset on Nov. 29, if it survives its close approach. • Target of Rosetta Mission: Comet 67P/Churymov‐Gerasimenko. • Art Chmielewski’d best joke: Ukrainian sources reported today that the Rosetta target comet Churyumov‐Gerasimenko discoverer Dr. Churyumov married his former graduate student Dr. Gerasimenko. Dr. Gerasimenko will now hyphenate her name, Gerasimenko‐Churyumov. Dr. Churyumov stated that he would like the comet’s name to reflect his complete Russian name including the otchestvo, father’s name – Chury, making the comet’s name Churyvich‐Churyumov‐Gerasimenko‐Churyumov. The matters became somewhat more complicated as Dr. Churyumov’s ex‐wife Natasha Harasimenko‐Churyumov stated via her attorney tha t her name needs to be adde d to 50% of her ex‐husband’s discoveries. Consequently, from now on the comet’s name will be legally changed to Churyvich‐Churyumov‐Gerasimienko‐ Churyumov‐Harasimenko‐Churyumov. What might have been a difficult linguistic problem was solved by the NEXT mission which was approved for an extitension. The NtNext‐NEXT will now retrieve the impactor from Tempel 1 and use it to hit Churyvich‐Churyumov‐ Gerasimienko‐Churyumov‐Harasimenko‐ Churyumov. “Our calculations show that the impactor will split the C‐C‐G‐C‐H‐C into 6 equal chunks, one for each part of the name,” said the Next‐NEXT project manager. Solar System Formation interstellar 4.6 Billion years cloud ago ‐‐ solar nebula & proto‐sun Key Questions: flattens 1. Whether interstellar ices survived into a the accretion shock and were rotating directly incorporated into comets? disk 2. Whether any chem. rxn were important in the part of the accretion disk in which comets formed? 3. Whether or not the details of the abundances of ice in comets are dust +gas good constraints on the solar sticks to form system? planets, asteroids & comets painting by Kazuaki Iwasaki HOT COLD early solar nebula FROST LINE young sun rock‐ice bodies rocky bodies comets Comets = Frozen Time Capsules Key Questions with which to unravel some of these mysteries to be addressed by Rosetta • D/H ratio • 17O • Amorphous/crystalline ice • Homogeneity/inhomogeneity of the surface New solar system H2O Along this line, geochemistry 17 –the relationship with rocks δ O determines the variation within the solar disc Prior H2O Along this line, mass Determines variation within the solar disc The Sun (Genesis) δ18O Modern Era of Comet Science Lyttleton’s Model Whipple’s model Sandbank Model Icy Conglomerate Model – Swarm of ice and dust – Consist mostly of ice with particllles sublimating layers – Based on limited – Based on indirect observations observation • Meteor shower – Non‐gravitational forces distributions – Meteor storm ejection • Eclipsing the sun‐ no shadow speeds and angles After Halley Comet 1986 • Confirmed solid body ….R.I.P Sandbank Model • But… – Low AlbedoÆ darker than soot, no ice – Low Bulk densityÆ porous?? – JtJetsÆ not uniform sublimation – Not spherical‐‐> irregular Halley’s comet taken by Giotto spacecraft on shape body March 13th, 1986. Solid nucleus was confirmed. Model Adaptations Rubble Pile Model Fluffy Aggregate Model Icy Glue Model • FtFragments are more • SlltilSmall particles wea kly • consitist o f lbldlarge boulders tightly packed, and bound to each other, fasten by icy dust grain welded together by forming a porous, open mix called the Whipple collision-induced structure with large glue evaporation and internal void spaces • Could explain the jets subsequent freezing of •Shoemaker-Levy event found on Halley ice. supports model : strength •Failed to support the • Shoemaker-Levy event Shoemaker Levy event supports model : tensile •No such reservoir of strength boulders exist as of now Data Results ‐ Inhomogeneities ? TlTempel 1 Wild 2 BllBorelly ≠ ≠ •Smooth surface areas, craters, •More Spherical layered •Bowling Pin shaped •Steep slopes, overhang, •Several mini‐outbursts •Brighter smooth terrain in preserved craters the middle, rugged ends, •High porosity and low density‐ mottled terrain ‐> loose aggregates? •Pre‐solar grains •Prominent collimated and •Particle size = 1‐10 μm vs. 10 ‐ •Jets, outgassing‐‐> 100 μm pre‐impact disintegrating fan ( like Halley) jets •Homogenous albedo •Large cohesive strength: icy •Hot dry surface dirt ball • Sunlit surface T above •Low albedo w/ bright spots sublimation T •Low albedo w/ bright spots •No craters‐ weak surface? •Similar to solar and CI • Crystalline silicate and other chondritic material (A&C) high T materials??? Comets from Afar: Shoemaker-Levy 9 (SL9) SL9 broke into pieces during a close encounter with Jupiter in 1992 and Impacts by disrupted collided with Jupiter in objects can make crater chains like this one on July 1994. Ganymede New Issues: Do we have comet ‘geology’ such as cryo-volcanism or planation? DI: V e verka etal (2012) Stardust-NExT: Veverka et al (2012) DI: Belton & Melosh (2009) US Rosetta Experimenter Workshop, 2/6/2012 14 Dana Point, CA 1965 Caltech Black Student Union Claudia Alexander graduation from UCLA: 1985 Windows to Adventure! Will be adding Rheasilvia into Book 1 (Mountains) Where to find me today! (May, 2013) 1. Astronomy Wise 2. Pasadena Now • pasadenanow.com/main/red‐ phoenix‐rising‐at‐litfest 3. Literary Network for the Baltimore Urban Book Festival • Thelitearynetwork.com /2013/ 04/30/claudia‐alexander‐ interview‐baltimore‐urban‐ bookfestival‐featured‐author 4. African‐American Author Expo • Amazon Author Page • Amazon.com/clauda‐ alexander/e/B008GN871M • And catch me in June at the Liemert Park Village Book Festival Sources of Inspiration • Ray T. Reynolds & Pat Cassen (Ames Research) – Jupiter Orbiter Probe (Io volcanic paper) • Yvonne Pendleton (Ames Research/NASA HQ) having a family will cause a hit on your career, but its OK! • CTR – Published & Published but Perished just the Same! (cartoon on his office wall! – interested in just about everything) • TIG –a vision about comet exploration & the future of finite differencing methods • Chris Jones (JPL – how to manage) • Roberta Johnson (UCLA, UM, UCAR –it’s OK to do both education and science!) Total Solar Eclipse (France, 2000?) [h[Chris was th]here!] Ray FkFrank C. Krishan Linda S..