THE PLANETARY REPORT SEPTEMBER EQUINOX 2014 VOLUME 34, NUMBER 3 Planetary.Org

THE PLANETARY REPORT SEPTEMBER EQUINOX 2014 VOLUME 34, NUMBER 3 planetary.org

BEYOND HUMAN VISION TURNING UP THE COLOR ON SATURN’S ICY MOONS

TESTIFYING FOR SCIENCE C VOLATILES ON MERCURY C EXOPLANETS: HONING THE HUNT ADVOCATING FOR SPACE CASEY DREIER is director of advocacy for The Planetary Society. A Key Witness for Exploration Planetary Science Gets Its Day in Congress

THE E-MAIL ARRIVED early ownership rights of natural science community and the on a warm morning during resources collected in space important work they do,” the final days of August. It to private companies. said House Science Commit- was from a staff member Jim’s testimony focused tee Chairman Lamar Smith on the U.S. House of Repre- on two major points: (R-TX) in a prepared state- sentatives Subcommittee on 1. Advances in planetary ment before the hearing. “I Space, writing to let us know science depend heavily hope that [the White House] that in a week and a half on planetary explora- is paying attention to today’s there would be a hearing on tion missions, and discussion.” the state (and fate) of plane- 2. Today’s dollars pay for The hearing was a clear tary science and, by the way, tomorrow’s missions. sign that The Planetary So- would The Planetary Soci- Although planetary science ciety’s continued advocacy ety’s president be interested looks strong, it’s because for the health and future in testifying? the current suite of missions of planetary exploration ABOVE On September 10, Yes—yes, he would. were paid for in the past. The missions is working. That 2014, Planetary Society Eleven busy days later, Jim rate of new missions being success is a direct result President Jim Bell [center] Bell arrived in Washington, built today has decreased of our members’ efforts to testified before the U.S. D.C. to address the uncertain substantially. As current contact their representa- House of Representatives future of planetary science missions age and end, there tives, and their donations Subcommittee on Space about the importance at NASA. As a professional will be few replacements in support of our programs. of continued funding planetary scientist, he un- ready to continue explor- Little known fact: Congress, for planetary science. derstands the major scientific ing the solar system. In fact, for the most part, does questions of his field inside after 2017, there will be no not pay for its witnesses to and out. As president of The NASA spacecraft exploring travel to D.C. to speak. The Planetary Society, he gets the outer planets or inner Society was able to provide the importance of continued planets. Since advances in travel for Jim Bell to testify space exploration for society planetary science depend in front of Congress thanks at large. In short, he was a so heavily on new data from to the generosity of you, perfect witness for the sub- spacecraft, there will be a our members. committee. drop in science activity in Congress, particularly The hearing, Exploring these crucial areas. These the House of Representa- To hear Jim Bell discuss his Our Solar System: The ASTER- gaps can be mitigated, Jim tives, has strongly support- Congressional appearance, listen to this episode OIDS Act as a Key Step, took argued, by restoring the ed planetary exploration in of Planetary Radio: a close look at the recent budget to historical levels as both its monetary appropri-

bit.ly/1m8hWqD cuts to NASA’s Planetary soon as possible. ations and policy authoriza- Photo: Tushar Dayal for The Planetary Society Science Division initiated by The congressional repre- tions. We’re building better the White House in 2013. It sentatives on the subcom- support in the Senate and also examined a proposed mittee were receptive and in NASA. Our message is Read Jim’s full written bill, the American Space they enjoyed seeing samples getting out there—planetary testimony [pdf download]: Technology for Exploring of the stunning images of science is great exploration bit.ly/1v4yv8G Resource Opportunities In our solar system that we bang for the buck—and last Deep Space (ASTEROIDS) provided for the testimony. month’s hearing testifies Act, which would grant “We value the planetary to that.

2 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 CONTENTS SEPTEMBER EQUINOX 2014

ADVOCATING FOR SPACE A Key Witness for Exploration 2 Jim Bell testifies on Capitol Hill.

COVER STORY Blue Pearls for Rhea 8 Paul Schenk creates color-enhanced maps of Saturn’s icy moons.

Missives from MESSENGER 14 Rebecca Thomas describes a surprisingly volatile-rich Mercury. DEVELOPMENTS IN SPACE SCIENCE Honing the Hunt 20 Bruce Betts talks about a new exoplanet project, and OSETI getting back on the rails.

DEPARTMENTS 4 Your Place in Space Bill Nye reports on The Planetary Society’s Strategic Plan.

6 Happening on Planetary Radio Fascinating guests and some special live events!

6 On Planetary.org New things are happening all the time on The Planetary Society’s blogs!

7 Questions & Answers Looking back at the Sun?

7 Factinos A Neptune-sized planet with clear skies!

19 What’s Up? A meteor shower and a partial solar eclipse.

22 Snapshots from Space The view from Pillinger Point.

Mars and the full Moon over Saint Peter’s Basilica. Photo: Tushar Dayal for The Planetary Society 23 MySky

ON THE COVER: Cassini, like all robotic explorers we launch into deep space, has deepened our understanding of our solar environs in many ways—some anticipated and some not. Dialing up Cassini’s infrared, green, and ultraviolet filters draws out details in the surfaces of Saturn’s icy moons that we cannot see in natural color wavelengths. This map of Enceladus’ far side shows the redepositon of icy dust (pink and yellow) from the “tiger stripe” vents (cyan tinted) at the moon’s South Pole.

CONTACT US The Planetary Report (ISSN 0736-3680) is published quarterly at the Editor DONNA E. STEVENS The Planetary Society editorial offices of The Planetary Society, 85 South Grand Avenue, Art Director LOREN A. ROBERTS for HEARKEN CREATIVE 85 South Grand Avenue Pasadena, CA 91105-1602, 626-793-5100. It is available to members of The Copy Editor AXN ASSOCIATES Pasadena, CA 91105-1602 Planetary Society. Annual dues in the United States are $37 (U.S. dollars); Technical Editor JAMES D. BURKE General Calls: 626-793-5100 in Canada, $40 (Canadian dollars). Dues in other countries are $57 (U.S. Science Editor BRUCE BETTS E-mail: [email protected] dollars). Printed in USA. Third-class postage at Pasadena, California, and at Chief Operating Officer JENNIFER VAUGHN Internet: planetary.org an additional mailing office. Canada Post Agreement Number 87424. Director of Communications ERIN GREESON

Viewpoints expressed in columns and editorials are those of the authors and do not necessarily represent positions of The Planetary Society, its officers, or its advisers. © 2014 by The Planetary Society. All Rights Reserved. The Planetary Society and The Planetary Report: Registered Trademarks ® The Planetary Society. Planetary Radio and Planetfest ™ The Planetary Society. YOUR PLACE IN SPACE

COFOUNDERS CARL SAGAN BILL NYE is chief executive 1934–1996 officer of The Planetary Society. BRUCE MURRAY 1931–2013

LOUIS D. FRIEDMAN Executive Director Emeritus

BOARD OF DIRECTORS Chairman of the Board DANIEL T. GERACI Founder & co-CEO Investing in the Future Arithmos Financial Innovations That’s What We Do at The Planetary Society President JAMES BELL Professor, School of Earth and Space Exploration, Arizona State University

Vice President HEIDI HAMMEL IN THE COURSE of just about any human ing addition to the staff. You may already be Executive Vice President, Association of Universities for Research in Astronomy undertaking, be it laying out the streets of a reading Media Producer Jason Davis’ illuminat- Chief Executive Officer BILL NYE city, rotating crops, getting the kids to school ing blog, and you’ll soon be enjoying the videos Science Educator on your way to work, or deciding what pitch by Merc Boyan, another new media producer. Secretary C. WALLACE HOOSER to throw to the next batter in a baseball game, Our executive assistant Whitney Pratz has Associate Professor of Radiology, University of Texas we want to have a plan. We want to figure streamlined everyone’s workday, especially Southwestern Medical School

G. SCOTT HUBBARD out just what we’re trying to accomplish Jennifer’s. Digital Marketing Manager Karen Professor, Department of Aeronautics and Astronautics, and then come up with a way to get it done. Hames has improved the performance and Stanford University Well, ever since I took over here four years the overall look of our e-mail and marketing Treasurer LON LEVIN ago (I just celebrated my employment anni- communications. If you’re a Society volunteer, SkySevenVentures

ALEXIS LIVANOS versary), the Board of Directors and many of thank you; I’m sure you’ve been in touch with Research Professor, Faculty Associate you have wanted the Society to have a plan—a Kate Howells, our dedicated, Canada-based Engineering & Applied Science, California Institute of Technology strategic plan. Thanks to the diligence of our volunteer network manager. I am delighted JOHN LOGSDON that many of you have already heard from our Professor Emeritus, Space Policy Institute, chief operating officer Jennifer Vaughn and The George Washington University the staff, along with our superb consultant new director of development Richard Chute; BIJAL “BEE” THAKORE Regional Coordinator for Asia Pacific, Warren Riley, we have an excellent strategic he brings valuable wisdom and experience to Space Generation Advisory Council plan. Look for it soon in mailboxes and on our operations. Our new director of commu- NEIL deGRASSE TYSON Astrophysicist and Director, planetary.org Hayden Planetarium, . nications is Erin Greeson; she will make a big American Museum of Natural History The main goals of the plan are to help us difference in how we connect with the world FILLMORE WOOD Vice President and Regional Counsel, achieve our mission and vision of empowering and, especially, with you. As a member, you BP, retired

INTERNATIONAL COUNCIL the world’s citizens to advance space science are the reason we all came to work today. ROGER-MAURICE BONNET Executive Director, and exploration, so that people everywhere International Space Science Institute can know the cosmos and our place within it. EUROPA UNITES CAPITOL HILL YASUNORI MATOGAWA Associate Executive Director, The team and I have talked the plan and goals Jupiter’s moon Europa has gotten a great deal Japan Aerospace Exploration Agency

MAMORU MOHRI through. We feel we can achieve our three-year of attention recently, because people in the Director, National Museum of Emerging Science and Innovation goals by August 21, 2017, when a total eclipse space industry, and in the government sector RISTO PELLINEN of the Sun will darken a swath from Northwest that funds exploration, are coming to realize Director of Science in Space Research, Finnish Meteorological Institute to Southeast right across the United States. It how straightforward it might be to fund a ADVISORY COUNCIL BUZZ ALDRIN will be a big day for the Sun and, we hope, a mission out there and look at the plumes RICHARD BERENDZEN JACQUES BLAMONT big day for the Society. that may be streaming through the cracks in ROBERT. D. BRAUN DAVID BRIN The big idea behind the big ideas is to be Europa’s surface—a shell of water ice covering JAMES CANTRELL FRANKLIN CHANG-DIAZ even more influential, to promote an even an ocean twice the size of our own. So in July, FRANK DRAKE OWEN GARRIOTT more engaged and enthusiastic citizenry that we held an event on Washington, D.C.’s Capitol Photo: Tushar Dayal for The Planetary Society GARRY E. HUNT BRUCE JAKOSKY embraces the importance and optimism of Hill to raise awareness of the opportunity, THOMAS D. JONES SERGEI KAPITSA space exploration, so that humankind can importance, and fundamental awesomeness CHARLES E. KOHLHASE JR. LAURIE LESHIN look farther and deeper into space, make of such a mission. What if there’s something JON LOMBERG ROSALY LOPES HANS MARK extraordinary discoveries, and advance our alive out there? BOB MCDONALD JOHN MINOGUE understanding of how we fit into it all. How Our own Casey Dreier set the stage. We had ROBERT PICARDO JOHN RHYS-DAVIES hard could it be? wonderful presentations from NASA’s Chief KIM STANLEY ROBINSON DONNA L. SHIRLEY To help us grow, we have hired several Scientist Ellen Stofan and Europa Mission KEVIN STUBE LORNE TROTTIER new people, each of whom is an outstand- Study Scientist Bob Pappalardo. It was great.

4 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 YOUR PLACE IN SPACE

Congressmen John Culberson, Lamar Smith, our cultures. My dad often gave me access to and Adam Schiff showed up and contributed. his tools. I remember spending a lot of time Whether or not you’re from the United States, measuring things with a metal tape measure. this was a remarkable example of how space I suspect our LightSail design team did as brings out the best in us. These gentlemen well. Our sails are deployed with metal ribbon are from different political parties and might “tape measure” booms. The Japanese engi- often disagree, but here they are like-minded neers, most of whom are quite a bit younger and motivated to make the mission happen. than I am, grew up with origami, the art of I wrapped it up with my talk on “P.B. and folding paper. And sure enough, their solar J.” or the Passion, Beauty, and Joy of explora- sail designs involve extraordinary, elegant, tion and discovery. Everyone was impressed and efficient methods of folding and packing by the science, and by the attendance of more the sail material. It’s just cool. than two hundred young staffers, people who As I toured the spacecraft display area in the want to see NASA take us to this new, exciting lobby, where JAXA has models of Hayabusa, place—a place where we will certainly make IKAROS, and several other Japanese-built astonishing discoveries. spacecraft, a group of about thirty Japanese students recognized me. I was stunned. Appar- ABOVE In July, The VISITING JAXA ently, the “Science Guy” television show makes Planetary Society I recently made my first trip to Japan and my its way to a sector of the Japanese educational hosted “The Lure of first visit with our colleagues at the Japanese system. I gave each kid a Planetary Society pin. Europa” on Washington, D.C.’s Capitol Hill. Aerospace Exploration Agency ( JAXA). It was wonderful to see the students’ enthusi- Here, Bill explains the I met with Makoto Yoshikawa at JAXA’s asm on the other side of Earth. importance of a new Institute of Space and Astronautical Science. mission to the Jovian We discussed the Society and our deeply PROGRESS ON LIGHTSAIL-1 moon to a crowded shared interest in solar sailing. He and his And finally, I must mention thatLightSail-1 room. At his side is team are as eager as any NASA principal inves- passed its Day-in-the-Life test, showing that the Jet Propulsion Laboratory’s Europa tigator in trying to get a new solar sail mission the sail can perform its key functions in space. Mission Study Scientist funded. I got a brief tour of their clean room/ The whole team gathered on the campus of Bob Pappalardo. final assembly building, which is strikingly Cal Poly San Luis Obispo to watch it unfurl similar to others I’ve visited in the U.S. and its sails and pass the major systems test. For Europe. (I guess to get air clean enough for a full report on the day’s activities (and to spacecraft assembly, we all have to abide by watch the sail deploy), go to bit.ly/1mVgXut.

Photo: Tushar Dayal for The Planetary Society the same laws of physics.) Especially gratify- People around the world will be able to ing, and just plain fun, was meeting with the watch it from here on our planet’s surface, young engineers who are monitoring Japan’s as well as in space from its own onboard Interplanetary Kite-craft Accelerated by Radia- cameras. It will be a fantastic experience for tion Of the Sun (IKAROS) solar sail (see the July/ citizens of the world. Together we can engage August 2010 issue of The Planetary Report), people in space exploration; together we can and planning the next sail mission. change the world. As an engineer raised in the United States, I was struck by how we all are influenced by

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 5 QUICK SCANS

HAPPENING ON

PLANETARYplanetary.org/radio RADIO LIVE: WE SEE THEE RISE: THE CANADIAN SPACE PROGRAM We welcomed 1,600 Canadian space enthusiasts to the University of Toronto in October for our celebration of Canada in space! Guests included Canadian space writer Elizabeth Howell, University of Western Ontario planetary scientist Gordon “Oz” Osinski, and Canadian Space Agency astronaut Jeremy Hansen. bit.ly/1qjyuqP

LIVE: MAVEN ARRIVES AT MARS! The United States’ latest guest of the Red Planet entered orbit on the evening of September 22, 2014, and the crowd at Planetary Radio Live was watching with fingers crossed.bit.ly/1mztkf5

MIGUEL ALCUBIERRE, INVENTOR OF WARP DRIVE? Distinguished physicist Miguel Alcubierre developed the general relativity-based model for warp drive 20 years ago, but he doubts it will ever be a reality. bit.ly/1wfqH2F

ALAN STERN AND A BIG MILESTONE ON THE WAY TO PLUTO New Horizons Principal Investigator Alan Stern discusses passing through Neptune’s orbit on August 25, as well as MAVEN and a new Uwingu initiative. bit.ly/1mOGJuJ

THE SEARCH FOR EXTRATERRESTRIAL POLLUTERS? Harvard student Henry Lin has led work that determined the soon-to-be-launched James Webb Space Telescope may be able to detect an alien civilization by analyzing pollution in its atmosphere. bit.ly/VjGRKV

Find these shows and our entire archive of Planetary Radio at planetary.org/radio! ON PLANETARY.ORG PROJECTS UNFURLING SAIL Video from LightSail’s Day-in- the-Life test. bit.ly/1mVgXut SPACE IMAGERY AMAZING VIEWS BOOK REVIEW FROM INDIA Mars LONG-DISTANCE THE NIXON SPACE Orbiter Mission delivers on its AUTO MECHANIC DOCTRINE John promise of stunning views of Exhaustive detail about Logsdon’s new book shows Mars. bit.ly/1vppB5i Curiosity’s wheel damage, its

how the post-Apollo era was causes, and possible solu- Illustrations: NASA/ESA/R. Hurt, JPL-Caltech defined by Richard Nixon. tions. bit.ly/1z1mWxt bit.ly/1yHuLgR SCIENCE UPDATE LOOKING INTO THE FUTURE NEWS MARS UPDATE Emily FLYING TO EUROPA EARLY ARRIVAL Jason Lakdawalla comments on the FUN IN 60 SECONDS Van Kane looks at potential Davis figures out why Orion fourth full drill hole on Mars RANDOM SPACE FACT issues for designing a is on the launchpad early. and speculates on wild rock Videos coming soon on suitable mission to Europa. bit.ly/1yCQsPb fractures. bit.ly/1pCX45Q planetary.org! bit.ly/1ryyWZp

6 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 FACTINOS

SCIENTISTS HAVE DISCOVERED clear skies and steamy water vapor on a gaseous, Neptune-size planet outside our solar system. The planet is the smallest for which molecules of any kind have been detected. The planet, HAT-P-11b, is located 120 light- years away in the constellation Cygnus. Unlike Neptune, this planet orbits close to its star— about once every five days. Scientists believe it to be a warm place with a rocky core and gaseous atmosphere. Clouds in a planet’s atmosphere can block QUESTIONS AND ANSWERS the view to underlying molecules that reveal information about the planet’s composition In popular astronomy books and history. Finding clear skies on a Neptune- size world is a good sign that other smaller and magazines, the Sun is al- planets might have similarly good visibility. Q most invariably depicted as In the new study, which was reported in just another bright star in Pluto’s dark the September 25, 2014 issue of Nature, the sky. Are there plans to have New Hori- researchers set out to look at the atmosphere zons look back and take a picture of the of HAT-P-11b, not knowing if it would contain clouds or not. They used Hubble’s Wide Sun from Pluto’s distance? Field Camera 3, and a technique called — Rafael Moro-Aguilar, Madrid, Spain transmission spectroscopy, in which a planet is observed as it crosses in front of its parent ABOVE Scientists have Great question! While the Sun is star. Starlight filters through the rim of the discovered relatively clear just one of many stars, it’s still planet’s atmosphere and into a telescope’s skies, illustrated above, on lens. If molecules such as water vapor are the brightest star in Pluto’s sky HAT-P-11b, an exoplanet A present, they absorb some of the starlight, by quite a bit. When New Horizons pass- about the size of Neptune. leaving distinct signatures in the light that es by Pluto on July 14, 2015, its distance Until now, all exoplanets reaches the telescope. observed in this size have from the Sun will be almost 33 times Using this strategy, Hubble was able to been found to have high the distance between Earth and the detect water vapor at HAT-P-11b. The team then cloud layers that blocked Sun. The Sun will be over a thousand used NASA’s Kepler and Spitzer telescopes to any detection of molecules verify that the water was, indeed, emanating times dimmer there than it is on Earth, in their atmospheres, from the planet. but even that will be too bright for the as depicted below. The results from all three telescopes spacecraft’s two imaging instruments: demonstrate that HAT-P-11b is blanketed in Ralph (its visible and infrared imager/ water vapor, hydrogen gas, and likely other spectrometer), and LORRI (Long Range yet-to-be-identified molecules. The scientists plan to examine more exo-Neptunes in the Reconnaissance Imager). We’re worried future and hope to apply the same method that taking pictures of the Sun might to smaller super-Earths—the massive, rocky damage the instruments before the ex- cousins to our home world with up to ten tended mission to fly by Kuiper belt ob- times the mass. ject (KBO) targets takes place. However, “The work we are doing now is important

Illustrations: NASA/ESA/R. Hurt, JPL-Caltech after New Horizons flies by a KBO, risk- for future studies of super-Earths and even smaller planets, because we want to be able ing these instruments will not matter to pick out in advance the planets with clear any more, so we could try it then. We atmospheres that will let us detect molecules,” just haven’t planned that far out yet—for said Caltech’s Heather Knutson, a coauthor on now, our eyes are on Pluto! the study. —Amanda Zangari —from NASA Southwest Research Institute

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 7 PAUL SCHENK maps icy moons and is a co-investigator on New Horizons, and a participating scientist on Dawn and Cassini.

Blue Pearls for Rhea All mosaics and images: NASA/JPL-Caltech/SSI/Paul Schenk, Lunar and Planetary Institute Color-Mapping Saturn’s Icy Moons

THE FIRST FIFTY YEARS of solar system ex- Britain, has been the star, but Mimas, Tethys, ploration have surprised us with many sci- Dione, Rhea, and Iapetus also have not dis- entific marvels and insights, but no one, not appointed. The maps and high-resolution even the great, pioneering space artist Chesley mosaics of these moons not only reveal scien- Bonestall, anticipated the fascinating vistas tific surprises, they bring out the best in these the planets would reveal. Mars Reconnaissance small worlds. Orbiter and rover images of the Red Planet have a stark beauty all their own, like the Painted FIRST FULL-COLOR MOON MAPS Desert in Arizona, and Europa often resembles Global color mapping of Saturn’s classic a Jackson Pollack painting in the right light. Yet midsize icy moons (those known before the

ABOVE In this Cassini mosaic, it is subtle, majestic, ringed Saturn that has a start of the Space Age) is now essentially constructed from infrared special place in our imaginations. complete, thanks to ten years of Cassini’s (IR), green, and ultraviolet Cassini has been streaming stunning images orbital operations. Cassini’s orbital tour was (UV) images, splotches of blue lie scattered along of Saturn to Earth since 2004. While the designed to map these moons piecemeal. the equator—somewhat ringed planet and its large moon Titan have Because the Saturnian system is so densely like a string of pearls—on certainly lived up to expectations, many of the populated, each moon could be visited Saturn’s icy moon Rhea. The planet’s icy moons have become unexpected up-close only a few times. There have been blue patches were formed stars in Cassini’s show. By turning on the color more than twelve targeted encounters with when ring particles in orbit switch in our mapping process, these little ice Enceladus but only six with Dione and two around the moon hit its heavily cratered surface, worlds have now come into their own. with Iapetus, for example. These encounters disrupting its soil. The Every planet we map in detail surprises us, were at distances of less than 3,000 kilome- scene is 650 kilometers and Saturn’s moons are no exception. Encela- ters (1,860 miles) or so. Thanks to planning (about 400 miles) long. dus, barely measuring 600 kilometers (about by Cassini team members such as Cornell 370 miles) across and no larger than Great University’s Paul Helfenstein and Tilmann

8 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 LEFT Enceladus looks pretty enough in a “natural” color image (left) taken through All mosaics and images: NASA/JPL-Caltech/SSI/Paul Schenk, Lunar and Planetary Institute Cassini’s red, green, and blue filters. But if we bump up its colors beyond the range of human vision using those same IR, green, and UV colors (right), interesting things begin to emerge. Not only do the bluish walls of Denk of Berlin’s Free University, the space- sometimes beyond, and it is in this range that recently formed fractures craft returned images from different regions the color differences really pop out. stand out, but the moon’s or hemispheres during these encounters, to orange and pink global surface pattern becomes more be reconstructed later. More distant encoun- A MOSAIC OF THOUSANDS OF IMAGES pronounced. The pink areas ters filled in the remaining gaps. How are such maps produced? Each new are where fine particles falling Like most planetary cameras, and unlike map is made from more than a thousand out from the icy moon’s imaging spectrometers, the Cassini Imaging individual images, obtained in four distinct south polar jets are thickest. Science System (ISS) camera acquires each spectral channels, or layers. The first layer color filter image separately for later trans- is the base map, constructed of hundreds of mission to Earth. Cassini must also do its the highest resolution clear filter images of

mapping in the form of multiple frame each body. This filter has the best transpar- mosaics of those areas in view during each ency to light and covers the visible spectral encounter. Most of these mosaics were range. Base map resolution depends on acquired in three colors, and they have now the resolution of the majority of the images, been assembled into the first seamless, high- which were chosen to highlight feature defi- resolution full-color maps of these bodies. nition. For Iapetus and Rhea the map reso- The natural colors of these moons are muted lution is 400 meters, Dione and Tethys 250 and slightly greenish in cast, but Cassini also meters, and Mimas 200 meters per pixel. At mapped in a color range extending beyond 100 meters, Enceladus has by far the best human vision. Our human color vision mapping coverage for any icy satellite. The ranges from approximately 400 to 700 nano- color images were selected to provide the meters in wavelength. The new Cassini maps best color resolution at each wavelength. are in the ultraviolet (UV) and near-infrared Ideally, we selected color images acquired at (IR) range, from 340 to 930 nanometers and the same time as the base map images.

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 9 Rhea Mimas

Mapping starts as individual clear, IR, of cratered regions on Rhea, I noticed an ABOVE Cassini’s new color green, and UV images are calibrated to odd, bluish spot on its equator. More on this maps of Saturn’s icy moons remove electronic camera and charge-cou- interesting feature later, but being curious reveal many differences pled device (CCD) effects. Each image is I wanted to know if there were other such among them. Rhea’s surface then registered into what we call the global spots on Rhea. Sure enough, a color mosaic is divided into dark and brighter sides (the pearls are control network to properly position it on to the east showed several more bluish spots, too small to be seen here). the surface, re-projected to a common map also on the equator. In fact, bluish spots Mimas is dominated by the format, photometrically adjusted to remove were strung more than halfway along Rhea’s Herschel impact crater, but the effects of global shading, and then digi- equator like an enormous string of bluish its bluish equatorial zone tally combined to make a global map in each pearls! Here was a mystery, one requiring a stands out. Tethys, too, is dominated by a big crater but color filter. The three color maps are then more complete global map. also features a large fracture merged with the clear base map to make the If Rhea has “blue pearls,” what about her system (shown here), a bluish final map. siblings? The next logical step was to make

equatorial zone (left) similar color maps of all six of the larger airless, icy All mosaics and images: NASA/JPL-Caltech/SSI/Paul Schenk, Lunar and Planetary Institute to Mimas’, and a reddish moons. These maps show that several of the darkening on one side. On moons have dark, reddish discolorations bright and dark Iapetus, the equatorial ridge is visible. In on their leading and trailing hemispheres, the areas between the moon’s easily understood as discolorations due to hemispheres, the ridge is E-ring dust and magnetospheric alteration partly ice covered and stands by charged particles, respectively. None of out from the dark material. the other moons have the same blue pearls, RIGHT One of Rhea’s “blue but Mimas and Tethys have something just pearls” is seen up close as weird: wide bands of bluish to “UV-ish” in this perspective view NEW DISCOVERIES AND NEW PUZZLES discoloration along their equators. Broad of its heavily cratered Although it was always planned to eventually and diffuse, these bands stretched across landscape. This Cassini IR, produce global color maps of these moons, their leading hemispheres like giant cum- Green, and UV mosaic was the maps and the discoveries they unlocked merbunds (like Earth’s Moon, Saturn’s obtained at a resolution of 130 meters per pixel and is were results of serendipity. For example, in moons are locked and keep one side facing approximately 85 kilometers the process of producing a high-resolution Saturn and one side facing forward). (about 50 miles) wide. stereo (3–D) mosaic and topographic map Here were some new puzzles revealed

10 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 SATURN’S ICY MOONS

Tethys Iapetus

in the color patterns of Saturn’s icy moons. STRINGS OF BLUE PEARLS I called some of my colleagues, and we set Back to those beautiful blue pearls on Rhea. to work figuring out what we were seeing. These small spots form irregular discolor- Chris Paranicus, of Johns Hopkins Univer- ations a few kilometers across along the sity’s Applied Physics Laboratory, had been equator, separated by 50 to 100 kilometers using Cassini’s Magnetospheric Imaging In- (30 to 60 miles). Curiously, they are always strument (MIMI) to look at the behavior of found only on the locally highest spots on the high-energy electrons trapped in Saturn’s equator. This pattern is similar to another one magnetic field. He found that they impact of Cassini’s great discoveries: the 20-kilometer the surfaces of these moons in a pattern (12 mile)-high topographic ridge on Iapetus, exactly the same as our equatorial UV color also found only along the equator. bands on Mimas and Tethys. Three months How does a monstrous ridge resemble after this discovery, Cassini’s Composite a faint set of blue spots? The maps show

All mosaics and images: NASA/JPL-Caltech/SSI/Paul Schenk, Lunar and Planetary Institute Infrared Spectrometer (CIRS) found that that the ridge on Iapetus is not continuous the color patterns also correlate very well but broken into isolated knobs and shorter ABOVE Bright, icy patches lie with a thermal anomaly, a cold temperature segments along the equator, in roughly the on the flanks of a 10-kilometer pattern commonly known as the Mimas/ same pattern as what we see on Rhea. The dif- (6.2 mile)-high mountain Tethys Pac-Man Feature, indicating that the ference between the two is that the ridge on in this perspective view of impact of the electrons alters the grain size Iapetus has mass and height, while the blue Saturn’s strange, icy moon Iapetus. These hills are part and compaction of these icy surfaces in ob- pearls on Rhea are merely discolorations on of the satellite’s famous globe- servable ways. Here is a classic example of an otherwise undisturbed surface. girdling equatorial ridge how planetary processes are revealed when One of the more interesting ideas to and mountain system, which we explore with a comprehensive suite of in- explain the ridge on Iapetus, put forward by probably formed long ago struments at many wavelengths. European Space Agency’s Wing-Huen Ip, was when a dense, orbiting ring system re-accreted back onto its surface. This view is 100 PAUL SCHENK is a planetary research scientist at the Lunar and Planetary Institute in Houston, kilometers (62 miles) wide. Texas, where he studies the cratering, volcanic, and geologic histories of the outer planets’ icy moons. He also uses colors, topography data, and high-resolution imaging to map those icy moons. On his days off, he sometimes goes diving wearing an old diving suit and brass helmet and is something of a diving historian. He also flunked out of art school.

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 11 ABOVE Rhea’s recently formed Inktomi crater appears to glow pale yellow in this three-color (IR, green, UV) Cassini view. This 50-kilometer (30 mile)-wide crater ejected bright ice over a broad that a ring-like mass of particles formed in ally hit the surface at very low grazing angles, area. The blue-rimmed craters at left are older. orbit around Iapetus, possibly from a large hitting the first high obstruction that gets in impact event, and that some of this mass their way. On Rhea, not many particles hit BELOW LEFT Bluish ice re-accreted back onto the surface along the and only the regolith is disturbed, exposing is visible along the inner equator. This novel idea was not considered deeper ices. On Iapetus, many millions of tiny walls of Bagdad Sulcus, very plausible, or at least very likely, when it particles hit the same obstructions, slowly ac- one of Enceladus’ active was first proposed in 2007. With the discov- cumulating a narrow pile of debris along the “tiger stripe” vents. This IR, green, and UV view was ery of a similar (though much less massive) equator, hence a long set of ridges. obtained at 35 meters-per- feature on Rhea, the concept of temporary pixel resolution and is 30 rings forming around satellites becomes ENCELADUS REPAINTS ITSELF kilometers (about 19 miles) much more plausible, indeed likely, as Enceladus, with its active jets and plumes across. The pinkish area several of my colleagues have since shown at the South Pole, always seems to steal is covered by fine material deposited from the icy jets. in numerical models. Ringed satellites are the show, and it should be no surprise that another of the profound discoveries of the Enceladus is the most colorful of Saturn’s icy BELOW RIGHT Temperature Cassini mission. moons. Several factors combine to make this maps of Mimas and Tethys How does one construct a ridge from a so. First, Enceladus’ surface is geologically from Cassini’s Composite ring? It’s relatively simple. Ring particles younger than the other moons and has not Infrared Spectrometer orbiting moons of giant planets do not last had as much time for erosion, which tends show cold areas identical to the bluish regions seen long but either dissipate into space or slowly to mute geologic colors. Second, the geologic in the global maps on (think centuries) spiral in toward the surface. activity on Enceladus results in continual the preceding page. With no atmosphere, the particles eventu- fracturing and exposure of new crust at the

Pac-Man on the Moons of Saturn Mimas Tethys Mimas/Tethys Pac-Man Feature image: NASA/JPL-Caltech/GSFC/SWRI 95K 90K

80K 80K

Mimas Tethys 65K 70K

12 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 SATURN’S ICY MOONS

surface. Third, some of the ice-rich, colorful dust from the plumes and jets at the South Pole returns to its surface. When we looked at the first color maps of Enceladus, they appeared different from the others. There was a global symmetry, with opposite hemispheres redder than the rest of the surface, but the pattern was offset 40 degrees from where we expected it to be. When I showed this map to my colleagues, one of them said, “We have seen this pattern, too.” As I was mapping color on Enceladus, Sasha Kempf of the University of Colorado and Jurgen Schmidt of Finland’s University of Oulu had been modeling what happens to the dust-sized grains of ice from these plumes. Most of this icy dust escapes to form the giant E-ring around Saturn but some of the dust returns to the surface, mostly in two giant tongue-like extensions from the South Pole that extend northward beyond the equator. Our color map, showing two large areas brighter in the UV spectrum (or bluer) than normal, matched this pattern Color maps with their subtle hues also give us ABOVE Global maps of almost exactly. Here was direct evidence a more realistic sense of what these surfaces Enceladus (top) and Dione that Enceladus was repainting itself with a look like from a human perspective, and are (bottom) show surprising diversity of features. The kind of extremely fine “snow,” with accu- somehow more intuitively insightful than yellow and pink colors mulations up to meters or tens of meters in the grey-tone images and mosaics that are of Enceladus betray the some areas. often published. Humans have a strong aes- redeposition of ice dust Many other areas on Enceladus show in- thetic sense of natural beauty, especially on from the jets at its South triguing color complexities related to local their native planet. Color mapping of plan- Pole. Dione, however, is geologic history. Tectonically fragmented etary surfaces thus helps us leap beyond the affected by radiation particles altering the regions have complex color patterns. The scientific information gleaned and provides backside (left) and turning most striking color differences are associ- a unique human look at nature’s handi- it dark, broken only by the Mimas/Tethys Pac-Man Feature image: NASA/JPL-Caltech/GSFC/SWRI ated with relatively young, deep fractures. work. Each of the planetary bodies we have network of bright fractures. The exposed walls of these fractures are looked at across the solar system, including The brighter forward side even bluer than the plume dust deposits and the moons, has proved to be a unique world at right is covered in dust from Saturn’s E-ring. The perhaps similar to the striking bluish ice we with its own inherent geology and native bright splotch on Dione is often see in tourist pictures of polar glaciers beauty. One can only wonder what we will the young 30-kilometer- here on Earth. find when we start exploring the thousands wide crater Creusa. of other planetary bodies being discovered INSIGHTS FROM COLOR in our galactic neighborhood. Mapping in color helps us unravel the geologic histories of all the icy moons, in- More information about Paul Schenk’s icy cluding Enceladus, Dione, and the rest of moons mapping project is available on the Saturn’s family, and has been directly re- Lunar and Planetary Institute’s website at sponsible for several interesting discoveries. lpi.usra.edu/icy_moons.

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 13 REBECCA THOMAS is a PhD research student at The Open University, U.K.

Missives from MESSENGER New Views of Mercury Reveal a More Volatile-Rich World

ONE OF THE MOST EXCITING findings of the change radically. MESSENGER has sent back MESSENGER spacecraft currently orbiting a wealth of invaluable data: images of the Mercury is evidence that the planet is rich entire surface at unprecedented resolutions, in volatiles (substances that readily change topographic data from its laser altimeter, and from solid to vapor at low temperatures). For chemical and mineralogical data from its spec- instance, MESSENGER has detected higher- trometers. All this has led us to a surprising than-expected abundances of these substanc- conclusion: Mercury is neither dead nor dry. es on the planet’s surface, as well as land- With daytime temperatures exceeding 400 forms best explained by volatiles escaping degrees Celsius (750 degrees Fahrenheit), from within its crust and mantle. Mercury’s surface was never going to be a Prior to MESSENGER’s arrival we knew land of rivers and jungles. All the same, the that Mercury has a huge iron core, and the percentage of volatile elements at its surface leading hypotheses to explain this implied is startling. MESSENGER’s X-ray and gamma- that the planet would be volatile-depleted. ray spectrometers have detected ten times For example, processes in the early solar the sulfur content of the silicate portion of nebula may have meant that the building Earth and a higher potassium-to-thorium blocks for Mercury were iron-rich but vola- ratio than on Mars. This is despite the fact

tile-poor. Alternatively, Mercury may have that both sulfur and potassium are relatively Images: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington suffered substantial volatile loss shortly after volatile. Though it is possible that internal it formed, either in a giant impact or by va- processes have concentrated volatiles at Mer- porization in the heat of the hot young Sun, cury’s surface and the bulk planet’s volatile ABOVE The region around Rachmaninoff, a double- as was recently suggested for dense exoplan- concentration is lower, it certainly does not ringed impact basin on ets close to their stars. look like Mercury is highly volatile-depleted. Mercury, is scientifically intriguing because it LEARNING ABOUT THE SURFACE A GEOLOGICALLY ACTIVE MERCURY shows evidence of hollows Data gathered by Mariner 10 in the 1970s and Volatiles are important to me as a planetary (surface features caused by sublimation of volatiles) and Earth-based radar observations did not chal- geologist because of the positive effect they explosive volcanism (including lenge these hypotheses to any great degree. have on so many of the processes that make a the largest such deposit on The surface looked old and cratered, and planet geologically active. For example, they Mercury, at upper right). though there were indications of volatiles lower the melting temperature of rock and in permanently shadowed craters near the favor volcanism, and their presence in the North Pole, they could have been delivered crust enables movement of faults. Addition- from outside by cometary impact. However, ally, volatiles at the surface lead to all kinds of after MESSENGER reached Mercury in 2008, fascinating geomorphological processes—just made three flybys and then settled into orbit, look at Mars or Titan—and volatiles in magma our view of the innermost planet has had to can lead to dramatically explosive eruptions.

14 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 190 km MESSENGER

53.5 km

The more we look at Mercury’s surface, LEFT These high-resolution the more we see confirmation that volatiles images of hollows in dark, low reflectance material are in play there. Its most intriguing (and (LRM) at the rim of Sholem downright beautiful) surface features are the Aleichem crater show their small, haloed depressions known as “hollows.” detailed morphology. They Clusters of hollows with diameters from one have broadly flat floors with kilometer (0.6 mile) to hundreds of kilome- some rough blocks, and ters occur all over the planet’s surface, usually their margins are very crisp, suggesting that they formed in impact craters. They look like the surface 4 km recently in geologic terms. has been eaten away, leaving flat-floored depressions about 50 meters deep. Bright, BELOW The impactor that bluish material on their floors and in a halo formed Mercury’s de Graft around them made them stand out even in crater seems to have exposed dark LRM rock. Sometime lower-resolution Mariner 10 images, and they after that, hollows formed were initially dubbed Bright Crater Floor all over the crater’s floor and Deposits (BCFDs). What is really surprising peak structures, as seen in about hollows is that they look so fresh: their these magnified views. The

Images: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington margins are crisp and they are not superposed hollows’ formation was by impact craters, large or small. Because probably due to sublimation of the LRM at the surface and the subsequent loss to space.

41 km 10 km

30 km

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 15 344 km 33 km

ABOVE Bright, relatively red counting superposed impact craters is our surface volatiles should have been lost by deposits form a “line of fire” best method of dating planetary surfaces from now? The answer to this quandary is impact at the margin of an ancient orbit, this lack of cratering means it is quite cratering. As mentioned above, most hollows impact basin, and they possible hollows are forming even now. are in impact craters. Craters with hollows surround pits that we believe to be explosive volcanic vents. So what do hollows have to do with vola- are almost always either in the dark substrate The close-up shows Kuniyoshi tiles? The way they cluster to form wide, known as low reflectance material (LRM) or crater, a very young crater relatively flat-floored areas makes it improb- they expose LRM in their interiors. It seems southwest of the line. able that they are the vents of volcanic erup- that LRM is a volatile-bearing rock and that Kuniyoshi’s freshness suggests tions, so our best guess is that they form by fresh exposures of it result in volatile loss and that it, and the explosive volcanism within it, may be the loss of volatile material from the planet’s hollow formation, leaving behind the eye- less than a billion years old— surface. Considering the searing temperatures catching bright material. very young in Mercury terms! reached at Mercury’s daytime, the prime can- How LRM formed in the first place is the didate mechanism for their formation is subli- next important question. Mercury’s crust mation: volatile elements near the surface are is very thin, so could it be upper mantle

heated, go straight from the solid state to gas, material? Or is it the original crust of Mercury, Images: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington and are lost to the exosphere. The distribution formed at the dawn of the planet’s history? of hollows across the planet’s surface does The answer to this is essential for determining seem to confirm this. Surface regions that whether LRM’s high volatile content is a result receive more heating from the Sun have more of a high bulk volatile content within Mercury, hollows than generally cooler areas. Addition- or whether it has built up through concentra- ally, hollows in those colder areas are more tion of volatiles in one particular substrate. frequently associated with volcanic vents than hollows elsewhere, which may mean heating RECENT EXPLOSIVE VOLCANISM from within can also provide the energy While hollows show a high concentration of required for volatile loss in areas where the volatiles at the surface, our best probe of the Sun’s heat is less dominant. planet’s interior is volcanism. There has been This begs the question: if solar heating a lot more volcanic activity on Mercury than strips volatiles away from the surface, why we used to think. Lava plains cover 27 percent do we see fresh hollows? Surely, all the near- of the globe, and vents surrounded by bright,

REBECCA THOMAS is in the final year of her PhD research into the geology of the planet Mercury, making new discoveries about the innermost planet using data from the MESSENGER spacecraft. She has also investigated extremely recent flows on the Cerberus Plains of Mars.

16 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 MESSENGER

169 km 42.5 km

red deposits across the planet seem to be the This is what we think the bright, red, diffusely ABOVE The pyroclastic result of widespread explosive volcanism. margined deposits around central pits are. At deposit northeast of What’s more, this volcanism was long-lived: last count, we have found these deposits at Rachmaninoff is the largest on Mercury, spanning 130 large-scale lava plains have been dated up 150 locations on Mercury. The deposits can kilometers from the center to 3.5 billion years ago, and smaller effusive be enormous: the largest, northeast of the of its vent. It appears that and explosive eruptions appear to have con- Rachmaninoff basin, extends up to 130 kilo- the vent may actually be two tinued into at least the last 2 billion years, meters (about 80 miles) from its vent. It takes or three conjoined volcanic and probably as recently as 1 billion years a very high volatile concentration to eject pits, suggesting that the site of eruption moved over time. ago. This is despite the fact that, as a small particles to that distance, at least as much as body with a high surface-area-to-volume ratio, the concentration present in such eruptions Mercury would be expected to cool faster on Earth. than a larger planet like Earth, leaving less The important question here is where the energy for magma melting. That cooling has volatiles are coming from. One option is that also led to global contraction and lithospheric they may not begin in the magma at all. When

Images: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington thickening, which hinder magma ascent even rising magma hits shallow seawater or a lake or if magma is being generated at depth. aquifer on Earth, violently explosive eruptions As mentioned earlier, volatiles reduce the can occur. So far, the evidence does not point melting temperature of rock, so the more toward such a strong contribution from non- volatiles are present in Mercury’s crust and magmatic volatiles. Hollows are our clearest in- mantle, the easier it is to melt it. However, the dicators of volatiles in the crust, and though ex- detection of long-lived volcanism alone is not plosive volcanism often occurs near them, the enough to prove there are volatiles at depth scale of eruption does not seem to increase if in Mercury. Other processes could account there are more hollows or if hollows are closer for it; for instance, insulation of the planet’s to the vent. While we cannot rule out some in- interior by a thick outer megaregolith, as has corporation of volatiles from the rock through been proposed to explain similarly long-lived which the magma rises, the evidence as it volcanism on the Moon. A much better indi- stands doesn’t point to sudden mixing with a cator of the presence of volatiles is the wide- large body of subsurface volatiles. spread occurrence of explosive volcanism. That leaves the magma itself as the main Volcanism becomes explosive when volatiles source of the volatiles, which is exciting in the magma or in its environs expand and because it may indicate that Mercury’s mantle rip the magma to pieces, spraying out frag- is volatile-rich. But here we have to tread ments that fall to create pyroclastic deposits. carefully. The volatile concentration at the

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 17 MESSENGER

ABOVE A bright cluster time of eruption isn’t necessarily the same as would lead to a volatile-depleted planet. of hollows etches an that in the magma at depth—volcanic systems Some theories, such as early vaporization of area within an unnamed are much more complex than that. On Earth, much of the planet’s rocky mantle by the Sun, basin on Mercury. This is the only area within volatiles often concentrate in magmas during probably need to be thrown out completely. the basin in which hollows storage in a subsurface magma chamber. Others have to be modified to account for are found. To the bottom left Volatile-poor minerals crystallize out first, what we’re now learning about Mercury’s is part of the peak ring of the leaving the remaining melt volatile-enriched. composition. For instance, new versions of basin. This peak ring has Additionally, the magma can be enriched in the giant impact hypothesis have volatiles re- been modified by subsequent volatiles by incorporation of melted volatile- accreting after the impact. impacts. This is a high- resolution observation, at rich wall rock. Our understanding of both hollows and ex- Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington 21 meters per pixel, so the full The evidence does point to subsurface plosive volcanism will benefit from the next image is about 27 kilometers storage of this kind on Mercury: volcanic vents six months of observations by MESSENGER, (about 17 miles) square. often form groups or overlap each other, in- as it gathers data from lower altitudes before dicating that they originate from one shallow impacting the surface next March. After that source body from which the site of eruption we have a lot to look forward to from BepiCo- varied over time. That means that the far- lombo, the joint ESA and JAXA mission that flung pyroclastic deposits do not necessar- should be arriving at Mercury in 2024. Com- ily indicate incredibly volatile-rich magma at positional analyses will be the key to under- depth. Still, to be concentrated in this way, standing both hollows and explosive volca- volatiles did need to be originally present in nism and figuring out what they mean about the magma or its environs, so, as with hollows, the planet’s bulk volatile content and the pro- explosive volcanism is an excellent sign that cesses that have concentrated it. The better Mercury has significant volatile content. we understand Mercury, the better we understand the early history of our solar system as UNDERSTANDING MERCURY’S FORMATION a whole. It’s endlessly fascinating how small- All this tells us that we need to go back to scale features on planetary surfaces can give those proposed formation mechanisms for us the answers to some of the biggest ques- Mercury and seriously reconsider those that tions of all.

18 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 SOCIETY TRAVEL WHAT’S UP? by Bruce Betts

IN THE SKY

A partial solar eclipse is visible October 23 from most of North America. The Geminid meteor shower peaks December 13 and 14. Often the best meteor shower of the year, its 100 meteors per hour may be seen from a dark site. Bright Jupiter Lake Titicaca is in the pre-dawn east in October, getting higher as the weeks progress. In October, Saturn sinks lower in the early and a Total evening southwest as days pass. Reddish Mars stays in the Lunar Eclipse early evening southwest throughout northern autumn. SEPTEMBER 19-OCTOBER 3, 2015

Experience the archeological wonders of Peru and Bolivia on this South American adventure! We’ll visit Arequipa and drive up into the Andes to Puno on the shore of Lake Titicaca, situated at 12,507 feet and surrounded by spectacular peaks. We’ll visit the Floating Islands RANDOM and take a hydrofoil across the lake to La Paz, Bolivia where we’ll also explore the site of Tiahuanacu (Tiwanaku). We’ll enjoy the Total Lunar SPACE FACT Eclipse from Lake Titicaca and then wrap up our expedition in Cusco and Machu Picchu! With NASA’s MAVEN spacecraft and India’s Mars Orbiter Mission both recently successful at entering Martian orbit, there are Total Solar now seven working spacecraft at Mars, the most ever. Eclipse: Bali and Sulawesi, Indonesia FEBRUARY 27–MARCH 13, 2016 Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington TRIVIA CONTEST Join us in Indonesia to see the Total Solar Eclipse on March 9, 2016! You’ll also visit the world’s finest orangutan reserve for close looks at these magnificent primates, along with proboscis monkeys, gibbons, Our March Equinox contest winner is Stefan Maas of and more! The itinerary includes Kadidiri Island, situated in the Togian Bethesda, Maryland. Congratulations! THE QUESTION WAS: Islands, Indonesia’s finest marine reserve. There, we will snorkel, What planet in our solar system has the shortest day/ kayak, and explore its underwater wonderland. The trip will conclude rotation period? THE ANSWER: Jupiter, at about 10 hours. in legendary Bali where we will learn about the Balinese culture, see the monkey forest, visit historic temples, and celebrate our adventure! Try to win a free year’s Planetary Society membership and a Planetary Radio T-shirt by answering this question: To get started on your adventure, go to planetary.org/expedition to What was the first successful Mars orbiter? download more information. E-mail your answer to [email protected] or mail your answer to The You can also contact Taunya at Betchart Expeditions to learn more: Planetary Report, 85 South Grand Avenue, Pasadena, CA 91105. Make sure you [email protected] include the answer and your name, mailing address, and e-mail address (if you 408-252-4910 (International) have one). By entering this contest, you are authorizing The Planetary Report to publish your name and hometown. Submissions must be received by December 1, 800-252-4910 (USA only) 2014. The winner will be chosen by a random drawing from among all the correct 408-252-1444 (Fax) entries received. For a weekly dose of “What’s Up?” complete with humor, a weekly trivia contest, and Betchart Expeditions a range of significant space and science fiction guests, listen toPlanetary Radio at 17050 Montebello Rd., Cupertino, CA 95014 USA planetary.org/radio. [email protected] betchartexpeditions.com

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 19 DEVELOPMENTS IN SPACE SCIENCE BRUCE BETTS is director of science and technology for The Planetary Society.

Honing the Hunt A New Exoplanet Project, and OSETI Rolls On

USING LASERS TO LOCK wobble is on the order of allowing you to compare DOWN EXOPLANET 10 centimeters per second. the data and know you are HUNTING Right now, radial velocity looking at real signals, not The Planetary Society is precision allows measure- just imprecise measure- launching a new collabora- ments of closer to only 1 ment variations. tion with Yale University’s meter per second. What is “In order to improve the exoplanet hunter Debra needed to improve preci- radial velocity method to Fischer and her team. We sion by that much is a very the precision needed to will support the purchase complex system with many detect true Earth analogs, of an advanced, ultra-stable parts. One set of those parts a wavelength calibration laser to be used in a complex involves calibration: making method is needed that is system they are designing sure you are measuring the more precise than anything to push radial velocity exo- same thing night after night, that currently exists,” says planet hunting to a whole so that what you record team member and Yale new level—a level intended as a specific wavelength in postdoctoral fellow Tyler to facilitate the discovery of 2014 measures as the same McCracken. “We rely on this Earth-sized planets around wavelength years from now, calibration to obtain nightly nearby stars. RIGHT Yale team member “The search for exoplanets Tyler McCracken poses is motivated by the question in front of the 4.3-meter Discovery Channel Telescope of whether life exists else- at Lowell Observatory’s where,” says Debra. “This Happy Jack site, close drives our interest in the to Flagstaff, Arizona. detection of planets that are Debra Fischer and her similar to our own world: team will use the telescope rocky planets with the po- to seek out 100 Earth-like planets around other stars. tential for liquid surface

water and plate tectonics; Top photo: Yale University Exoplanet Group; photo at right: Paul Horowitz worlds that might harbor life that we can recognize.” Finding Earth-size planets around other stars is extremely hard, to say the

least. The radial velocity Photo: Yale University Exoplanet Group technique measures the tiny wobble induced in a star by a planet’s gravitational tug. For an Earth-like planet in a star’s habitable zone (where liquid water may be stable on the surface), the

20 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 Honing the Hunt A New Exoplanet Project, and OSETI Rolls On

measurements and map out of hundreds of relatively big cranes and heavy-duty the wobble of the star over nearby stars for Earth-ana- welding equipment, new multiple years. This trans- log planets will begin. rails were installed and the lates to a requirement for To learn more about how roof now opens and closes, wavelength calibration that the calibration system works, using a lower electrical is stable over decades. Our go to bit.ly/TPS-exoplanets. current than ever before. solution to this problem is This is the only OSETI to lean on technology devel- BACK ON THE RAILS WITH search that scans the whole oped in other fields (namely OSETI sky (visible from Harvard, atomic, molecular, and Sometimes the most Massachusetts, that is) and optical physics) and to tune advanced space observa- it searches every possible their techniques to meet our tions—such as looking for night. The 72-inch telescope requirements.” laser pulse communica- and the first generation of Debra and her team have tions from alien civiliza- its amazing back-end elec- built a prototype in their lab tions—get interrupted by tronics date from 2006, ABOVE They just wore at Yale. But now they need rather mundane issues. and were funded by Plan- out from use! One of the to upgrade to a more stable, The Optical Search for Ex- etary Society members. broken rails from the more professional laser to traterrestrial Intelligence More recently, the system moveable roof protecting The get to the precision they (OSETI) project, carried received a major upgrade Planetary Society All-Sky need. That is where The out by Paul Horowitz’s to its electronics, designed Optical SETI telescope in Harvard, Massachusetts. Planetary Society comes group at Harvard University and implemented by Curtis The worn-out rails were in. Once we support the using The Planetary Society Mead, who was a graduate replaced and the roof is laser, they can integrate All-Sky Optical SETI Tele- student at the time (Curtis operating better than ever. it into their system and scope, suffered just such a has since earned his PhD). build a true science instru- hiccup a while back when Over the years, the system TOP A prototype of the ment, not just a prototype. the observatory’s roof liter- has also been adapted for Exoplanets Laser system sits in the laboratory Once it is thoroughly tested ally ran off the rails. completely remote opera- at Yale University.

Top photo: Yale University Exoplanet Group; photo at right: Paul Horowitz and understood, it will be The telescope is housed tion. It includes a weather combined with their other inside a simple-looking station and remote cameras new development, the building that protects it to ensure the right con- Extreme Precision Spectro- during inclement weather. ditions for observations. graph (EXPRES) spectrom- When conditions are right Curtis now operates the eter (funded by the National for observations, the 4-ton telescope on a regular basis

Photo: Yale University Exoplanet Group Science Foundation), and roof is rolled back horizon- remotely from California. that whole system and more tally on metal rails. After For even more infor- will be moved to the Dis- years of use, some of the mation about our OSETI covery Channel’s 4.3-meter rails were completely worn program, including the telescope near Flagstaff, out, and the roof no longer recent electronics upgrades, Arizona. There, the search worked properly. Using go to bit.ly/TPS-seti. Planetary Society members have helped make these projects—and many others—possible! Thank you.Thanks!

THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 21 SNAPSHOTS FROM SPACE EMILY STEWART LAKDAWALLA blogs at planetary.org/blog.

The View from Pillinger Point

THE OPPORTUNITY ROVER is now a mountain climber. Opportunity spent three years driving 12 kilometers (about seven miles) across the sandy wastes of Mars’ Meridiani Planum to reach the rim of Endeavour crater. The rover has spent another three years crawling around the rim of that crater, and is now scaling heights it has never reached before. Opportunity took the images that make up this sweeping panorama—across a ridge named Pillinger Point and down into the basin of Endeavour crater—with its Pancam on sols 3663 to 3668 (May 14 to 19, 2014). Pillinger Point is one of several locations along Endeavour’s rim where Mars Reconnaissance Orbiter spotted hints of clay minerals that might provide clues to a wetter and more clement Martian past. —Emily Stewart Lakdawalla Mosaic: NASA/JPL/Cornell/ASU/James Sorenson SEE MORE AMATEUR-PROCESSED SPACE IMAGES PLANETARY.ORG/AMATEUR SEE MORE EVERY DAY! PLANETARY.ORG/BLOGS

22 THE PLANETARY REPORT C SEPTEMBER EQUINOX 2014 SPECIAL OFFER FOR SOCIETY MEMBERS

I often read excerpts from The Planetary Report to my husband and children, and we enjoy exploring our planetary Spend a neighborhood—whether it’s pausing to view a bright rainbow at home or watching a meteor shower while on a camping trip. On Year In Space! April 14, 2014 my husband Bill took this photo of Mars and the full Moon over Saint Peter’s Basilica in Vatican City. The picture, shot from our hotel room, was taken with a Canon EOS Rebel The Planetary Society’s 2015 Year In Space Wall T2i. At the time, we didn’t realize that we were missing the lunar Calendar is back by popular demand. This large- eclipse back in the States! —Wanda Eyre, Everett, Washington format, award-winning wall calendar features more than 120 space images, hundreds of facts, sky events, space trivia, and an introduction by our

Mosaic: NASA/JPL/Cornell/ASU/James Sorenson own Bill Nye. Pay only $13.95 (or less, depending WANT TO SHARE YOUR SPACE IMAGE? Send us an e-mail with a jpeg on quantity ordered) and get free shipping within attachment (less than 5 MB) of your image to [email protected]. the United States when you use the Planetary Please use the subject line “MySky” and include a short caption (such as where Society discount. Order yours today by calling you took the image and, if appropriate, with what equipment) and credit line for the image. Please include just one MySky image per submission. Also, be sure to 800-736-6836 or visiting YearInSpace.com include your name, contact information, and membership number (it’s on your membership card and on the mailing label of your magazine). We’d also love to learn more about what is most important to you about being a member of The Planetary Society. Questions? E-mail [email protected].

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We Appreciate Our Loyal Friends

In November 1980, Dave Hagie responded to an intriguing ad in Omni magazine and became one of The Planetary Society’s earliest members. Soon afterward he signed on as one of our original volunteers and, from our first little office in Pasadena, began stuffing envelopes. “The first couple of years, between the volunteers and our direct-mail consultants, we sent out about 3.5 million invitations to join The Planetary Society. That helped the organization grow to 100,000 pretty quickly,” says Dave. Dave’s interest in the cosmos began in childhood, gazing at the night sky over Kansas City, Missouri. As an adult, his decades-long career as an accountant and field office manager with Pasadena’s Parsons Corporation was spent working half-time in Pasadena and half-time abroad, in Korea and all over the Middle East. One thing remained constant, though, and that was his devotion to The Planetary Society. One of his proudest achievements as a volunteer, he says, was successfully managing the Society’s move from 65 North Catalina—our (overstuffed) Pasadena headquarters of 25 years—to our current digs across town. As a longtime member of our New Millennium Committee, Dave also has been a Are you a longtime member? Do you have a special memory related to your membership? generous and reliable supporter of the Society’s work. If so, please share it with us by e-mailing We’re glad Dave (shown here sorting books in Photo: Loren A. Roberts for The Planetary Society it to [email protected]. our library) agreed to let us thank him here for his many years of membership, hard work, and To donate, volunteer, or give financial support. When asked what he’d like to a gift membership, visit see The Planetary Society achieve in the near future, Dave said, “I want to see us grow to 100,000 us at planetary.org members again, like we did in those early years.” With the help of our loyal supporters—people like Dave, and you—we know we can do it.