On the Cover: Volume XIV This infrared image of Jupiter was captured on Table of Number 6 July 18, 1994, with the 1O -meter Keck telescope at the summit of Mauna Kea on the island of November/Dece mber 1994 Hawai i. At lower left, the bright plume from the Contents impact of comet Sh oemake r- Levy 9's fragment G rises above the planet's eastern limb. Thjs picture was taken abou t 10 minu tes after the predicted time of the impact. In this false -color image, yellow represen ts the hottes t areas, and blue, the coo lest. In subse quent shots, this plume bright­ ened to outshine the planet and render it invisi ble Features Departments next to the extreme glare of the plume. Imag e: W.M. Keck Obse rva tory/lmke de Pater, NASA Today, and a Members' James Graham and Garrett Jemigan; 4 3 University of California, Berkeley Vision for Tomorro1N Dialogue In recent years NASA has been repeatedly We 're still hearing from members reacting attacked for lacking an overarching goal to to our recent special issue on planetary direct its activities. Administrator Dan protection. Plus, our article on the proposed Goldin has proposed a new purpose for the Pluto Fast Flyby has provoked a variety of From space agency: the search for planets like responses. our Earth. The 16 Ne~sand The Crash at Last: Revle1Ns Editor 8 Cornet Shoemaker­ Scientific American has put together a Levy 9 Collides provocative and comprehensive special With .Jupiter issue on a topic of interest to Planetary t is the purpose of The Planetary . As chunk after chunk of the fractured comet Society members: life in the universe. I Society to bring the excitement of slammed into Jupiter, observatories on Some of the big guns of science contributed exploring and investigating our solar Earth and in space gathered enough data to articles, and our faithful columnist gives system to as many people as possible overwhelm the scientists who had prepared his views of the contents. around the world. One of the prob­ for months for the events. The saga of lems we face in carrying out our pur­ Shoemaker-Levy 9 is not over yet; we only World pose is the indifference many people begin our coverage in this issue. 17 Watch claim the public has toward happen­ We depart from our usual format in this ings off our own planet. Who cares, 14 Live From Other issue to bring you a close look at the growing they ask, what happens on a planet Worlds: A Pilot Japanese planetary program. like, say, Jupiter? Electronic Field Trip Well , the events on Jupiter in July At The Planetary Society, we 've been 18 Readers' should prove to even the dourest searching for the past few years for new Service skeptic that the public's imagination ways to bring the excitement of exploration In this computer age, we have more choices can still be captured by planetary into the classroom. This is the story of one than just the printed page when searching happenings, both by the sheer specta­ project that melds computers, classrooms for good material for children to read. In cle of interplanetary collisions and and space technology. this year-end issue, we offer members a by their lessons for us on Earth. chance to sample the solar system through Comet Shoemaker-Levy 9 focused 15 Watching .Jupiter a CD-ROM as well as through books. the public's attention on the planets, World1Nide and it is now our job to make the The comet collision was all we could have 19 Society most of that interest. Our Jupiter wished for and more- what a spectacular Ne1Ns Watch program will continue beginning for our Jupiter Watch! Here we Here again is your chance to keep up with through Galileo's exploration of the share some of the highlights of this program the latest Society projects and events. jovian system and, with our mem­ so far, and look forward to continuing our bers' help and support, we can keep watch as Galileo approaches the giant 20 Questions and the public interest high. Watch these planet. Ans1Ners pages for coming events and ways Flight time to the closest star system, the you can participate in the planetary effects of gravity in space, and seasonal excitement. changes-you've asked us about many -Charlene M. Anderson disparate topics this time.

~;:C:~~~t,a2'ARif1o~~~~3S0~ ,o(~~~?~gg~~~ ggbll!~~~~~ \~~I~t~y ~~~~;~i~t~~~f~~:~e~~;: ~:~T~~~al~~~~li~te~~nNt~!h u~ab~l i2:::~~ u e, are $25 US dollars or $30. Canadian. Dues outside the US or Canada are $35 (US). Printed in USA. Third--class postage at Pasadena, California, and at an additional mailing office. Canada Post Agreement Number 87424. A Publication of Editor, CHARLENE M. ANDERSON Technical Editor, JAMES D. BURKE Assistant Editor, DONNA ESCANDON STEVENS Copy Editor. GLORIA JOYCE THE-PL.A~T1RV SOCIETV Production Editor, MICHAEL HAGGERTY Art Direc tor, BARBARA S. SMITH Viewpoin ts expressed in columns or ed itorials are those of the authors and do not necessarily represent positions of The Planetary Society, o .~-e- ¢ -& 0 its officers or advisors. © 1994 by The Planetary Society. o j j Board of Directors CARL SAGAN President Director, Laboratory for Planetary Studies, Members' Cornell University BRUCE MURRAY Vice President Professor of Planetary Science, Dialogue California Institute of Technology n LOUIS FRIEOMAN ExecutiveOirector NORMAN R. AUGUSTINE Chairman and CEO, Martin Marietta Corporation JOHN E. BRYSON Chairman and CEO, Southern California Edison JOSEPH RYAN Earthly but asking someone "how you feel" earlier than 2001 and arrive at O'Melveny & Myers Microorganisms about a particular issue is asking Pluto around 2010. STEVEN SPIELBERG Two items in recent issues of The for a lot of information-more It appears that the scientific director and producer LAUREL L. WILKENING Planetary Report (H. Jay Melosh's than can be provided by just one of goals of the Pluto Fast Flyby mis­ ChanceJJor, University of california, Irvine article in July/August and WF. three choices on a questionnaire. sion could be achieved at lower Board of Advisors Mellberg's letter in Members' -STEPHEN PERRIER, cost and with greater effectiveness DIANE ACKERMAN poet and author Dialogue, September/October) Fort Worth, Texas by using a JGA maneuver. The pri­ BUZZ ALDRIN state that viable terrestrial micro­ mary motivation for employing the Apollo 11 astronaut RICHARD BERENDZEN organisms were recovered from Which Way to Pluto? direct-trajectory concept seems to educator and astrophysicist parts of the Surveyor 3 camera Rob Staehle and his coauthors be a justification for using a high­ JACQUES BLAMONT Chief Scientist, Centre National after three years' exposure to the have written an excellent summary tech, microspacecraft design even d'Etudes Spatiales, France RAY BRADBURY lunar environment. It is true that of the proposed Pluto Fast Flyby when it is not required. poet and author the camera parts had been exposed mission. However, they have failed - ROBERT W FARQUHAR, ARTHUR C. CLARKE to the lunar environment for three to address the rationale for avoid­ Columbia, Maryland author CORNELIS DE JAGER years, but it is less clear that the ing the use of a Jupiter gravity­ Professor of Space Research, The AstronomiCdllnstitute at Utrecht, microorganisms had been. assist (JGA) to reach Pluto. (This I must applaud everyone who is the Netherlands FRANK DRAKE I was Surveyor project scientist . subject was hotly debated by a involved in the Pluto Fast Flyby Professor of Astronomy and Astrophysics, and custodian of the Surveyor 3 panel of space scientists and engi­ mission: the engineers and stu­ University of CalifornIa, Santa Cruz JOHN GARDNER parts returned from the Moon. A neers at the International Academy dents who are creating the tiny, founder, Common Cause person on my staff witnessed the of Astronautics Conference on advanced science components, MARC GARNEAU Canadian astronaut biological test that led to the find­ Low-Cost Planetary Missions last the team that is putting the mis­ GEORGIY GOLITSYN Institute of Atmospheric Physics, ing of terrestrial microorganisms April.) The advantages of the JGA sion together and making sure it Russian Academy of Sciences on the camera. He reported that a technique are readily apparent­ fits within weight and price restric­ THEODORE M. HESBURGH President Emeritus, breach of sterile procedure had either a much larger payload mass tions, the Society for its detailed University of Notre Dame occurred: an implement used in the capability or a smaller launch vehi­ account of the mission and even SHIRLEY M. HUFSTEDLER educator and jurist test was put down on a nonsterile cle requirement could be achieved the bureaucratic pressures that GARRY E. HUNT laboratory bench and then, without with flight times under 10 years. have resulted in the restrictions space scientist, United Kingdom SERGEI KAPI TSA re-sterilization, touched to the For example, an Atlas launch on today's spacecraft. Institute for Physical Problems, camera. It is, therefore, quite pos­ vehicle could deliver a 380-kilo­ Microspacecraft like the Pluto Russian Academy of Sciences GEN. DONALD J. KUTYNA (RET.) sible that the microorganisms were gram (835-pound) spacecraft to mission will bring humanity clos­ former Commander, US Space Command transferred to the camera after its Pluto in 9.5 years, or a Proton er to space than ever before, as JOHN M. LOGSDON Director, Space Policy Institute, return to Earth, and that they had launch vehicle could transfer a politicians become more willing George Washington University HANS MARK never been to the Moon. 500-kilogram (l,lOO-pound) pay­ to fund more missions in the face The University of Texas at Austin -LEONARD D. JAFFE, load in 8 years. The respective of increased success for less money. JAMES MICHENER Pasadena, California passage distances at Jupiter would What's more, the advanced instru­ author MARVIN MINSKY be 12.7 and 8.6 Jupiter radii, which ments mentioned at one point in Toshiba Professor of Media Arts and Sciences, Questionable should not require excessive your article (a science package Massachusetts Institute of Technology PHILIP MORRISON Questions? radiation shielding. Science pay­ weighing much less than a mod­ Institute Professor, One of the questions in your loads would be in the 50-to-70- ern planetary camera, high-gain Massachusetts Institute of Technology PAUL NEWMAN Planetary Exploration Survey in kilogram (11 0-to-154-pound) antennas as light as a telephone) actor the July/August 1994 issue of Th e range, which would be a great will awaken the public to the JUN NISHIMURA former Director General, Institute of Space and Planetary Report is vague, if not improvement over the current tremendous spin-offs that result Astronautical Science, Japan confusing. You ask the readers 10-kilogram (22-pound) baseline from an aggressive but restricted BERNARD M. OLIVER how they feel about the benefits of in the Staehle proposal. space program. NASAlA~:~eke~!~~~rogera,,~~ planetary exploration, then give Without the need to miniaturize Thank you for another informa­ SALLY RIDE Direc/or, California Space Institute, three choices: low, moderate or the science instruments, it's likely tion-packed issue. I always look University of California, San Diego, and former astronaut high. This question can be inter­ that costs could be reduced while forward to receiving The Planetary ROALD Z. SAGDEEV former Director, preted many different ways. Are increasing capability. Use of the Report, especially when it contains Institute for Space Research, you asking what the benefits could JGA technique would require a as much good news as this issue. Russian Academy of Sciences HARRISON H. SCHMITT be, what they should be or what launch in 2004, with the spacecraft -GEORGE BUCKINGHAM, former US Senator, New Mexico, and Apollo 17 astronaut they will be? reaching Pluto as early as 2012. Brandon, Manitoba, Canada S. ROSS TAYLOR Professorial Fellow, Because of the ambiguity, this This arrival date compares quite Australian National University, canberra question cannot be used to draw favorably with Staehle's direct­ Please send your letters to Members' JAMES VAN ALLEN any final conclusions. I understand trajectory proposal, which cur­ Dialogue, The Planetary Society, 65 North Professor of Physics, University of {owa the limitations of a short survey, rently is scheduled to launch no Catalina Ave, Pasadena, CA 911 06-2301. 3 Under Administrator Dan Goldin's leadership, NASA is reinventing itself. In the process, the agency is also searching for a vision to define its role, both as an agency of the United States government and as a leading force in humanity's exploration of space. On Thursday, May 26, 1994, Goldin proposed one possible unifying vision to members of the American Geophysical Union, gathered to hen my daughters were very young, I gave a talk celebrate the organization's 75th anniversary. at their elementary school. I started to describe What follows is an adaptation of that speech. W Earth and how it spins about its axis, and why we have day and night. I talked about the various planets, We invite Planetary Society members to about Mars and VerlUs. And I tried to tell them about the share their views of Goldin's suggested over­ outermost planet of the solar system, Pluto. I even de­ arching goal for NASA: the search for life­ scribed to them that there might be something beyond that sustaining worlds beyond our own. planet. And there were very, very happy faces in the room. 4 -Charlene M. Anderson Then, I told them about the Sun and how it provides Left: This Earth-like planet, sheathed in water and clouds, rotates at the center of a system of rocky moons. Do any worlds like this exist around nearby stars? Answers to questions such as this l could provide a focus for NASA. Painting: Joe Tucciarone

and prosper, to find new methods of producing food and fuel, to create new ideas and new technologies. Today, we fear global economic competition, ethnic strife, environmental degradation and an ever-increasing population on this very small planet. We are becoming a global society, and we realize we need a transforma­ tion- human, social and technological. All three are required in order to survive. NASA has an especially important role to play in pro­ tecting our planet. People are worried about global warm­ ing, changes in the ozone layer, deforestation, loss of biodiversity, and air and water quality. This is the reason for NASA's "Mission to Planet Earth," which is one way NASA will help accomplish the larger tr.ansformation. Another way NASA may.play a role in achieving this transformation is by helping to answer a new question we now face: "How can we all live together on our small planet?" The space station, first conceived as a symbol of dominance, now is a symbol of our new yearning to live in harmony with other nations. It may turn out to be not only a testbed for technology, but for learning how we can work together with other nations on an incredibly complex technological venture. Relevance must be at the heart of what we do- using the resources of space, and the technologies we develop to get there and operate-to better the lives of all people in our nation and the world.

In the ancient past, one of the reasons astronomers sought to map out the heavens and learn about the seasons was to improve agricultural production and planning. What they did was relevant to their people's needs, and those people understood that. There was a direct connection. In the recent past, there was also a direct connection between the space program and the American people's needs. For decades, the space program perfectly filled America's need to beat the Soviet Union, to demonstrate technological superiority over the "Evil Empire." The space program had a purpose. It had a mission. And throughout the Cold War, it had tremendous support from the American people. They were able to make that energy to the planet. And I made a mistake. I told them direct connection. the Sun was going to bum out in about 5 billion years. Then the Berlin Wall came down, and before our They were absolutely appalled; they were frightened. And eyes an old era crumbled. What is this new era that is their main worry was, what's going to happen to me? emerging? We don't know yet. We are struggling to de­ fine ourselves and redefine our science and space policies ~ :::: as we head into an uncertain new age. And we are strug­ This anxiety, this fear, is not a bad thing; it reflects our gling to make a transformation from a space program urge to survive. In the past, it has led us to explore new that for 35 years was a projection of power to one that is continents, to find new places where people might live relevant to human needs in the 21st century. 5 NASA is getting did it. The spacecraft is now producing spectacular results. Shortly after I arrived at NASA, we committed to a its house in order, launch date for GOES-8 of April 1994, and we did that too. GOES (for Geostationary Operational Environmental and we will soon Satellite) is now in final checkout in orbit. If all goes well, we intend to tum it over to NOAA (the National Oceanic and Atmospheric Administration) as a fully be ready to look operational system. America will no longer have to rent spacecraft from the Europeans, but will work together with them on joint systems to benefit people from each outward once of our countries. We are a leaner, more efficient NASA. We have re­ again. duced the cost of the Earth Observing System by more than a factor of2. We are proposing to fly five missions to Mars for about the cost of one Mars Observer. We plan to accomplish the objectives of the SIRTF (Space Infrared Telescope) mission for about one-quarter of the There is uncertainty today over how to do that. That's cost projected just a few years ago. And we have brought okay. It really couldn't be any other way. Those who down the cost of SOFIA (the Stratospheric Observatory cry for clarity in the midst of chaos are asking for a for­ for Infrared Astronomy) by a factor of2. We hope that mula for disaster. It will take time to think this through. we'll be able to start that in the not too distant future. We cannot expect this instant clarity as we leave the We are planning the Fire and Ice mission with the Cold War behind and we turn slowly toward the new Russians to go to the Sun and to Pluto. We propose to milleunium. do it for about one-third of the price projected only two But we need to begin working toward a unifying vision years ago. All quality science. We have just released an for the space program-an integrating goal that will de­ announcement of opportunity for small science missions fine our purpose. And a purpose that will strike a chord that go from design through operations and launch for in the hearts and minds of Americans. It won't happen $8 million to $12 million or less. overnight. It will take time, thought and imagination. We are reshaping the agency. Ifwe hold steady on our course for the next 10 years or so, we will be in a position to embark on a new direction for our space activities. It is NASA is getting its house in order, and we will soon be not too soon to begin thinking about what that direction ready to look outward once again. Weare reinventing might be. ourselves. We are doing what we said we'd do. We might send humans to Mars to search for signs of We absorbed a 30 percent budget cut in the last 18 ancient life or to establish ifthere is subsurface water. months because the president and Congress asked us to We might go back to the Moon, or visit a nearby asteroid. step up to the challenge oftoday's tough times. Even We might develop space commercially through industry­ though our budget has come down, we have started new government partnerships. We might do all those things programs-Mars Surveyor, Mars Pathfinder, Small Sat and more. (the Small Satellite Technology Initiative), the Relativity But tpday, I want to sketch out a different possibility. Mission (a gravity mission to empirically test Einstein's I want to begin a dialogue between NASA and the science theory) and NEAR (the Near Earth Asteroid Rendezvous). . community that will forge a new vision that connects Most of these programs will take two or three years to NASA and the American people- a shared vision that develop, not two or three decades, and will cost tens or all Americans can understand, and one that responds to hundreds of millions of dollars, not billions. their hopes and dreams. Even if we can't get started on And we have firmly started a number of large missions it for a decade or two, it could chart a path to the future. that were in the planning stages: the Advanced X-ray So here goes. What if, while protecting the precious Astrophysics Facility (AXAF), Cassini and the Earth resources on our own planet, and exploring our own so­ Observing System (EOS). We have made difficult deci­ lar system, we also commit to studying the universe with sions about how to spend our precious resources. We 've powerful observatories to do something extraordinary? brought a new accountability to NASA, instituted con­ I'm not sure whether these observatories should go on tract reforms and created a Program Management the Moon or in Earth orbit or in some near solar orbit, Council to keep our programs on track, hold them to but what if we used them to seek and discover planets cost and detect problems early. When they overrun, we around nearby stars? .~ cancel them. The American public expects no less. Wouldn't that very knowledge of their existence We redesigned the space station at the request of Pres i­ transform our understanding of our place in life, of our dent Clinton. We will have a safer, cheaper station that place in the universe? Provide hope? Shouldn't we set does more robust science, and does it sooner. We brought our sights on finding out whether there is a nurturing the Russians aboard as partners, also at the request of the environment beyond our solar system? president. We committed a year beforehand to repair the There is a host of stars within tens of light-years from 6 Hubble Space Telescope in December of 1993, and we Earth. Many planetary scientists now believe that plane- I invite you to tary systems may be common, and we know life did start in the hostile enviromnent of early Earth. So it is join us as we not out of the question that nearby stars might have planets capable of sustaining life. In the future, we will have the technology needed to turn to the future. image planets that might orbit nearby stars. It may be possible to infer through spectroscopic analysis of their atmospheres or the colors of their oceans whether or not For any vision to they are life-bearing, whether or not there is carbon diox­ ide, water and ozone. What a revelation that would be! be worthwhile, That would change everything- no human endeavor or human thought would be untouched by that discovery. it must be a Every society leaves behind a legacy. The ancient Greeks shared one. produced art, philosophy and the beginnings of theoretical science. The Egyptians built the pyramids of Giza. The Romans laid 50,000 miles of highway. And the Mayans built observatories to map the stars. Perhaps, just perhaps, the next generation's legacy out to the nation, how well it communicates with the will be an image of a planet 30 light-years from Earth American public. I've asked it to set goals not only for and the tools of technology it took to capture that image. cutting-edge science and exploration, but for the human Or perhaps it will be something else, something we haven't values ofleadership, teamwork, productivity and integrity. even dreamed of yet. We have to get ready scientifically I invite you to join us as we turn to the future. For any fairly soon. We would have to establish a technological vision to be worthwhile, it must be a shared one. foundation for imaging other solar systems-developing the needed telescopes and interferometers and other instrumentation. Some of the things NASA hopes to do in the near future The remote sensing observations made by our planetary will contribute to our hypothetical goal of discovering missions and by the Earth Observing System would help life-sustaining planets. The Solar-Terrestrial Probe series us design the instruments needed to observe the planets will study the plasma and magnetic environment that around other stars- make a ground truth, if you will, for couples the Sun and Earth. We hope SOFIA and SIRTF interpreting results. will make new observations-observations of stellar and In fact, we need to focus all of our space sciences on planetary formation processes. We hope to go to the edge the problem, starting with understanding how stars are ofthe solar system, to Pluto, and go back to Mars, and formed and how protoplanetary disks of dust and gas are get clues from asteroids, comets and other planetary formed around young stars ..We would need to understand bodies about the origin and evolution of the solar system. how planets are formed from this dust and gas, what they However, these will not be billion-dollar missions. They would be like and how they would evolve. And we need have to be small, fast, and we have to get them off in to understand how a habitable planetary environment can two to three years, not two to three decades. We can do evolve and be sustained, and be shielded from injurious it because the technology is here. stellar radiation and plasma particles around such planets. And a decade from now, we hope to have gone through The search for life-sustaining worlds could be a new, the whole of the solar system, defined the Sun-Earth unifying goal for space research. It's one possibility- by connection and completed the survey of the universe no means the only one or necessarily the right one. What across most of the electromagnetic spectrum. We would is clear is that we need goals like this that can integrate indeed, at that point in time, be ready for the next step. the space sciences into a simple statement that the Ameri­ can public can understand and give us a path to go down. We went to the Moon, and we had Apollo. We did unbe­ Let us begin. We need you to be part of something that's lievable planetary science. We did unbelievable space just beginning at NASA. We 've got a new team in place, physics. And we got started on space astrophysics. The and a funny thing is starting to happen. We're not just American public understood. All I'm saying is there talking about budgets and fiscal cycles and contract reform. needs to be an integrating theme. Not a set of disciplines We're talking about the future again. We're talking that perform a set of entitlements, but an integrated about working toward a vision that will integrate the theme that asks basic questions. space program, and give it the power and resonance to I have asked the newly formed NASA Science Council unify America once again, as we step out into the first to start articulating a vision for the role of space science light of a dawning age. in America. And I mean all the sciences- Earth, life, microgravity, planetary, fundamental physics and astro­ Daniel S. Goldin is the administrator ofN ASA and an physics. I've asked it to address the changing role of enthusiastic advocate of a strong, unifYing vision for space science in America, its priorities and how it reaches America's space program. 7 The C rash at Last: COl11et Shoel11aker-Levy 9 Collides With Jupiter

by Keith Noll

Twelve minutes after fragment G's impact, Peter McGregor took this infra­ red image of its radiant plume with the Aus­ tralian National University's 2.3-meter tele­ scope at Siding Spring. On Jupiter's right side, the bright puff of impact A has rotated into view. Image: Peter McGregor, Siding Spring Observatory

8 Top left: The impact sites of fragments 0 and Gresulted in this smeared bUll's-eye on Jupiter. NASA's Hubble Space Telescope took this picture on July 18, 1994, an hour and 45 minutes after Ghit the planet, creating the t was better, bigger, more spectacular than anyone had dared hope. With most of Earth's dark spot surrounded by a thin, dark ring. This fragment telescopic power trained on Jupiter, with the mighty Hubble Space Telescope in orbit and entered Jupiter's atmosphere from the south at a 45- I degree angle, and it appears that,the impact debris with the spacecraft Galileo approaching Jupiter, wave after wave of data flowed to SCientists, forming the large crescent shape flew back in that direction. The small, dark spot to the left of G's impact taxing their powers to understand what was happening, site is where fragment 0 hit on July 17,1994. The public and press were more excited than anyone had hoped, also overwhelming the , Right: In this Hubble Space Telescope image, eight impact sites are visible. From left to right, they are: the researchers but this time with demands for "instant science" and encapsulated explanations of ElF complex (barely visible on the planet's edge), the what they were seeing on Jupiter. As Planetary Report readers know, this sort of on-the-spot star-shaped H site, then tiny Nand 01, small 02 and R, and on the far right limb, the OIG complex. This picture theorizing is often erroneous; the true scientific story may not emerge for months to come, By is a composite of separate images taken through differ­ ent color filters to create "true color" renditions of then most of the popular press will have lost interest in Shoemaker-Levy 9 and the real story Jupiter's multicolored clouds. will only be told in the pages of technical journals, Images: Hubble Space Telescope Comet Team and NASA With this article by one of the scientists working on the SL9 impacts, we begin our coverage of this once-in-a-millennium event. Here are some of the early images from around the world and interplanetary space. As SCientists slowly work through the data and enhance the images, we will continue our coverage, and Planetary Society members will get a full report. - Charlene M. Anderson

July 16, 1994: A single fragment- a small fraction of condensed ices, in which case the designation chunk of solar system debris torn to shreds by the slight dif­ "comet" would be correct, or would they be relatively poor ference in gravitational pull across it during a grazing pass in these volatiles and high in silicate minerals and therefore by Jupiter two years before-plunges through 60 kilometers deserving of the name "asteroid"? What would be the ef­ (about 35 miles) of Jupiter's atmosphere every second. In fects of dumping so much energy into a small part of ' less than a minute, the density of the atmosphere becomes Jupiter's atmosphere? Would wr! see waves moving away too high for the fragment to push through. The tremendous like ripples in a pond? Would the clouds be altered, and kinetic energy is dissipated in a brief flash, an explosion of new circulation patterns formed? enormous energy. The experiments on the Hubble Space Telescope (HST), We knew this much about what would happen during the and at most observatories on Earth, focused on these very collision of SL9-officially named comet Shoemaker-Levy basic questions. Some projects proposed to look for specific 9 (1 993e)- with Jupiter well in advance of the actual event. effects; others were looking for anything that might turn up. On almost any clear night, a careful observer can see a Images would be used to search for clouds, and plumes, and miniature version of this enacted in Earth's starry sky as flashes, and to follow the evolution of any changes in the dust-sized grains achieve a moment of brilliance as they atmosphere. Spectra would be used to analyze the composi­ streak overhead. But size can be important, and nothing on tion of the fragments both before and after they hit, and also the scale of SL9 had ever been witnessed by human beings. to look for changes in the chemical composition of Jupiter's What would we be able to see? Giant flashes and plumes, atmosphere caused by the mixing and heating that the giant or nothing at all? How large were the fragments hidden in explosions would produce. the cocoons of dust? How massive? Were there single ob­ jects or many fragments in each condensation? How much Waiting for the First Impact energy would they deliver into Jupiter's atmosphere? What ,By 8:00 p.m. EDT (eastern time) on Saturday, July 16, the were the fragments made of? Would they contain a high Operations room at the Space Telescope Science Institute in 9 Above: Only Galileo' s instruments, out of untold numbers, had a direct view of Shoemaker-Levy 9's fiery death. The Jupiter­ bound spacecraft took these four images of fragment w's nightside impact on July 22, 1994, at a distance of 238 million kilometers (about 150 million miles) from the planet. These pictures were taken two and a third seconds apart. The first frame shows no impact, but in the next three a point of light appears, brightens and then fades. No one is sure yet

Left: This sequence of Hubble Space Telescope images chronicles the rise and fall of fragment G's plume after Gsmashed into Jupiter. The time elapsed from the first appearance of the small, bright feature in the top frame to its full-blown intensity and subsequent flattening and dissipation was 18 minutes. The plume is visible primarily by reflected sunlight, and the apparent gap between it and Jupiter's surface is the planet's shadow. Images: Hubble Space Telescope Comet Team and NASA

Baltimore was sweltering. Inside were 30 to 50 people- as of the misinformation following comet Kohoutek. We were many as could get in the door- far more than the usual one ready to emphasize that science begins with observation or two operators plus the half-dozen scientists on the official and that even the observation that nothing happened is a list. The first fragment of SL9 had hit Jupiter four hours valid, and interesting, scientific result. earlier. Rumors that something had been seen from the At about 5 :30 p.m., half a dozen of us had huddled ground were flying, and the excitement was uncontainable. around a radio and listened to a live report from South Real information about what had been seen was traveling Africa. The telephone link was cut off in the middle of the more slowly. The HST's brand new Wide Field/Planetary interview but lasted long enough for us to learn that astron­ Camera 2 had taken two orbits' worth of images of Jupiter omers there had not seen anything unusual. This was in line hours before, but because of the geometry of communica­ with our more pessimistic and conservative expectations. tions satellites the precious data had been written to one of A primary lesson that every scientist must learn is not to the tape recorders on board, waiting to be relayed to Earth. let expectations prejudice an experiment. The data are the Observatories in Europe, Africa and South America- at only source of truth in the end. However, it is literally im­ just the right longitudes to observe the crash of the first of possible not to include some guesses about what might be more than 20 pieces of the comet- were also at work. observed when designing an experiment or an observation About three hours earlier, Melissa McGrath, my col­ sequence. league at the Space Telescope Science Institute and a mem­ The comet fragments were estimated to be anywhere from ber of the science team, had come running excitedly down a few kilometers across down to boulder- or even sand­ the hallway, telling all of us to read the latest e-mail.Scien­ sized particles traveling in clusters. The range of possible tists observing Jupiter from Calar Alto in Spain had report­ effects of the collisions was equally broad, and while we all ed seeing a plume from impact A! This was not something secretly hoped for spectacular phenomena our skepticism we had expected to see from the impact of the first frag­ told us that the effects, if any, were more likely to be small. ment, one of the least bright "pearls" in the string. In fact, Other reports came over the e-mail. One South American we were already prepared to remind the hordes of reporters observatory reported seeing a spot at the impact site. An­ waiting in the auditorium that the brightest (and presum­ other reported no detection. Getting two positive reports ably largest) piece, fragment G, was not going to strike was encouraging, but the negative reports were puzzling. Jupiter until Monday morning. We did not want the expect­ We did not know what to expect. 10 ed disappointing results from impact A to lead to a repeat As the time for the Hubble's tape playback drew closer, n

whether these flashes depict the object's entry into Jupiter's atmosphere or the subsequent explosion and fireball. Fragment W was the last piece of the comet seen to hit the planet. Galileo will continue to return data and images of the event through January 1995. Once scientists integrate all the Galileo, Hubble Space Telescope and ground-based data, they will have an excellent account, from start to finish, of the Shoemaker­ Levy 9 story. Images: JPUNASA

Right: These are two close-up views of fragment G's impact zone. The image on the top was made in green (visible) light with the Hubble Space Telescope's Wide Field/Planetary Camera 2 (WFPC2). On the bottom is the same field taken through the WFPC2's methane filter. The thin, dark ring surrounding the G impact in the visible image is about 80 percent the size of Earth. The methane filter view suggests that the explosion may have occurred within Jupiter's atmosphere, because the rays of the ejected material do not point precisely to the center of the ring. Images: Hubble Space Telescope Comet Team and NASA

the room quieted. It would take a couple of minutes for and exclamations. We could hardly believe what we were each image to be transferred to the computer, and we seeing. The spine-tingling sensation of that moment is some­ would see each image in sequence. The first image had thing I will not forget. Superposed on Jupiter's normal been taken at about 4:10 p.m. EDT, or about 10 minutes clouds was a tremendous and beautifully symmetrical pat­ after the predicted impact time. Each following image tern of dark clouds. Like a bull's-eye, a perfectly circular would be about three minutes later. ring surrounded a dark streak where the comet chunk had Just after 8:00 p.m., the first image flashed on the screen entered Jupiter's atmosphere. Farther out was a spray of in a hushed room. Nothing but Jupiter was there. I bit my material shot back out of the bull's-eye by the enormous lip and thought about the last year of work I and the others energy of the explosion. This was an image taken almost in this room had done to prepare for this observation. If an hour after the previous one in the HST's next 96-minute something was going to be there, it should have been in orbit around Earth, and by this time the impact plume had this image. The next image was similarly blank. I felt my settled and the impact site had rotated well into view. hopes deflate. Fragment A had been late, but there could be no more Then the third image was displayed. A faint speck ap­ doubt: The week and month and year to come would be peared over the limb-just a few pixels, but in the right very interesting. place. This is the kind of signature a cosmic ray can make The rest of the week is hard for me to remember in when it hits the detector array, and even though the expo­ detail. Every day brought exciting new discoveries. The sure was short it was a possibility. Then came the fourth spectroscopy team that I lead was waiting for impact G, image. The speck was there again, this time more than a when we would get our first chance to see what kind of few pixels-definitely something real. material was being spewed out of the crash sites. The spec­ The room carne alive. Could this really be it? This image trum showed dramatic changes, and in ways that we did was taken almost 18 minutes after the predicted impact, not fully expect. We stayed up till early in the morning seemingly too late for what we were seeing to be from with stacks of books and papers, puzzling over the identifi­ that impact. Someone asked if the speck could be one of cation of the new lines in Jupiter's spectrum. Roger Yelle, Jupiter's satellites by chance in the way, and ran to get the a science team member from the University of Arizona, astronomical almanac. identified sulfur, S2, the next morning over breakfa ~t, and When the next image was displayed on the screen, a then the following day Sushil Atreya, of the University of collective gasp filled the room, then an eruption of cheers Michigan, and Paul Feldman, from Johns Hopkins Univer- 11 This mosaic of four images shows the aftermath of fragment R's collision with Jupiter on July 21, 1994. The upper images were taken with the ROKAM infrared camera on the McDonald Obser­ vatory's 2.7-meter telescope. The two lower images were taken at the same times as the upper ones, but they are CCD (charge-coupled device) frames taken with the D.B-meter tele­ scope. Brightening due to R's impact is visible in the upper right frame. Previous impact sites are still visible in the infrared. Images: ROKAM-Yongha Kim, University of Maryland; 8eth Clark and William Cochran, University of Texas. CCO­ Wayne Pryor. University of Colorado; Chan Na, Southwest Research Institute; and Anita Cochran, University of Texas

Using the 3.5-meter telescope at Spain's Calar Alto Observatory, scientists caught the first view of fragment a's impacts at Jupiter's lower left limb on July 20, 1994. Image: Calar Alto Observatory

12 ~------

Scientists at the South Pole had the unique advantage of being able to view the comet impacts nonstop, because from that vantage point Jupiter did not set but remained in view 24 hours a day. Using the 24-inch South Pole Infrared Explorer telescope, they were able to record the crash of fragment L. This time sequence (from upper left to lower right) starts with the still glowing remnant of the older K impact. In the next four frames, the L fragment hits, brightens and begins to fade. At lower right, L'5 remnants are to the left of K's. Image: Hien Nguyen, University of Chicago, South Pole Infrared Explorer

sity, identified carbon disulfide, CS2• The oxygen­ darker than Jupiter's clouds, maybe because of the containing molecules we had expected to find were sulfur compounds that were seen after the impacts. not there, but there seemed to be plenty of sulfur Now that the excitement and the news coverage molecules. Sulfur molecules are especially interest­ have died down, the more difficult tasks of care­ ing because they are one of the possible colorants fully looking at each bit of data, of comparing it in Jupiter's clouds, but no sulfur molecule had ever against theoretical calculations and then transform­ been observed before in Jupiter. ing results into scientific talks and figures and pa­ Exuberant astronomers from observatories pers, begin. Eventually, we may be able to say what around the world flooded the Internet with so the comet was made of, or even whether it was a many images and so much information that it soon comet at all. We may learn whether the material we became difficult even to read every new message. see is from the comet, or from Jupiter itself. My normally circumspect colleague Roger The answers to our questions will require a Knacke, observing at the United Kingdom Infrared time-consuming quantitative analysis ofthe data, Telescope on Mauna Kea, Hawaii, left an excited something that will take months. Already there are message on my answering machine during one of sessions and symposia planned for the October my four-hour sleep breaks, saying his group had meeting ofthe American Astronomical Society'S "looked into the maw of the explosion" of the R Division for Planetary Sciences, and for next May fragment and retrieved some very interesting data at the Space Telescope Science Institute. Undoubt­ on the composition of the hot plume. There was so edly there will be papers published for many years much to observe that nearly every investigation about the data gathered over the last weeks of July will have something to say about this complex 1994. And astronomers of following generations as phenomenon. well may want to study the papers we will write and the data we will archive because it may be Taking Stock longer than the time from the invention of the tele­ Only the earliest results are in at this time, just a scope to now before anything similar to the great month after the crash. As is evident on these pages, crash of SL9 will happen again. there was a lot to be seen in the images. There are plumes and clouds and waves in the atmosphere. Keith Noll is an astronomer at the Space Telescope The spectra have yielded a bounty of information Science Institute in Baltimor.e, Maryland. He is es­ on the composition of the impactor and also on pecially interested in the atmospheres and surfaces Jupiter. Surprisingly, the clouds of debris were ,ofthe many exotic worlds in our solar system. 13 Given The Planetary Society's conditions in one of the most remote areas commitment to education and of the world. They gave students intriguing interest in the use ofrobotics details about doing science in Antarctica, in­ and virtual reality in planetary cluding such things as safety precautions re­ exploration, we were happy to searchers needed to take to survive on the sea get involved in an innovative ice, as well as personal anecdotes about life endeavor that combines the two. at McMurdo Station, such as what was on the Developed and produced for menu for Thanksgiving dinner. public television by longtime Through another innovative on-line feature, Society members GeoifHaines­ "Researcher Q&A," managed by NASA's Stiles and Erna Akuginow, K-12 Internet project, scientists in Antarctica and elsewhere were available to respond via the project described here is computer to questions from youngsters and designed to stimulate students' teachers. Students could read researchers' interest in science and the responses to questions sent by other students, exploration ofother worlds. and they could then follow up with their It is a multimedia project that own inquiries or comments. One volunteer incorporates new technology expert (dragooned into this by Chris McKay, into the classroom. Our contri­ Planetary Society advisor) even worked on bution was a grant to help the project from his home in England and create a teacher's guide, and provided great information about future we are making videotapes Mars missions. available to the public. With Students were eager to participate when the your support, The Planetary opportunity arose to join Dale, via satellite Society will continue to be and telecommunications, during one of his there, blazing a path down the dives. Using regular school computers and information superhighway on modems, they were even able to drive Mars behalfof the exploration of One, the underwater robot, as well as a proto­ space.-Charlene MAnderson type surface rover in a test environment at NASA Ames, from thousands of miles away. For Live From Other Worlds, a compre- hensive teacher's guide was researched, de­ sing live, interactive television, Internet connections veloped and printed by the project team, with the assistance fJ and innovative classroom tools, students and teachers of the NASA Mission From Planet Earth Study Office. The have begun to go on electronic field trips to the fron­ hands-on activities were developed by a team of science edu­ tiers of scientific discovery. As part of a new public television cators, with the (much appreciated) collaboration of the SET! project called Passport to Knowledge, they are becoming Institute and The Planetary Society. Classroom teachers re­ active partners with research teams exploring remote places. viewed these activities for practicality and for intelligibility. The pilot program, Live From Other Worlds, aired in De­ The next phase of this ongoing project extends the eyes cember of 1993 as a miniseries ofthree 40-minute television and ears of its student audience to the entire continent of . programs. It linked students in the United States to NASA Antarctica, from McMurdo Station to the South Pole, and scientists working near McMurdo Station in Antarctica. from the Dry Valleys to the central west Antarctic ice sheet. Students participating live on camera in schools in Hawaii It looks at the coevolution of the continent and its life-forms, and Virginia, and in California at NASA's Ames Research ancient and modem-at the geology, climate, biology, Center, were able to communicate with researchers over­ history and future of one of the most fascinating places on and under-the Antarctic sea ice more than 10,000 kilome­ Earth- as well as at the ongoing enterprise of scientific ters (6,000 miles) away. discovery and at the researchers who are unlocking Antarc­ The explicit focus of Live From Other Worlds was a NASA tica's secrets. The four-part Live From Antarctica will air telepresence project researching robotic control techniques in on December 13 and 15, 1994, and January 10 and 19,1995. preparation for future planetary missions and, as part ofthe If all goes well, the January 10 program will include the NASAJNational Science Foundation Antarctic Space Analog first-ever live video broadcast from the South Pole. Like Program, surveying the underwater environment of McMurdo the pilot project, the upcoming miniseries will be supported Sound at depths never before explored by humans. The im­ by carefully coordinated print and computer materials for plicit message was the excitement of cutting-edge research students and teachers. and the personal satisfaction felt by young scientists like Future field trips will involve NASA's Kuiper Airborne robotics team leader Carol Stoker and diver Dale Andersen, Observatory, the Hubble Space Telescope, the 1997 landing both Planetary Society members. of Pathfinder on Mars and-if a current Discovery-class On-line, teachers and students were able to use computers mission is approved-perhaps even Live From the Moon! and modems to connect more personally with scientists by reading two field journals, "The Telepresence Project Research GeoffHaines-Stiles is a longtime producer and director of Log," kept by Carol, and "Dale's Dive Diary." In these science television, including "The Creation of the Universe, " regularly updated reports, the scientists described what they "Together to Mars?, " Carl Sagan's Cosmos and many Nova 14 saw, felt, thought and learned as they worked under difficult programs on space themes. watching . Jupiter Worldwide

by Susan lendroth and Carlos Populus

omet Shoemaker-Levy 9 has come and gone, and the the comet impacts in the larger context of how the solar first leg of Jupiter Watch is over. The comet impacts system continues to evolve. The evening concluded with a Cwere as spectacular as we had hoped, and our events chance for the audience to ask questions, and one woman around the world were successful as well. We've already delighted the speakers with a report about how her amateur begun work on the next focus of our program, Galileo' s astronomy group had observed a brightening ofIo during December 1995 arrival at Jupiter. one of the impacts. Gene Shoemaker asked her to send him Although we planned and cosponsored an array of activi­ the details, so the science continued even during our public ties in other places, we centered our main events during the events. predicted impact period, July 16 through 22, in Washington, Our Jupiter Watch tour group, 38 people representing DC-the political heart of the United States space program. seven nations and several languages, was on hand for the The Washington area was not only the focal point of our week's festivities. Their itinerary included many activities Jupiter Watch activities but also the unofficial comet-news geared to Society interests, including a visit to the National headquarters for scientists and reporters alike, with NASA Air and Space Museum's Paul E. Garber Restoration Facili­ Goddard Space Center and the Space Telescope Science ty and a private tour and lecture at Goddard, in addition to Institute, both nearby in Maryland, hosting numerous press our special Jupiter Watch events. conferences. The Society invited Gene and Carolyn Shoe­ maker and David Levy, the comet's discoverers, to the area More Jupiter Watch Highlights to participate in our activities. Beginning in April, and right up to the second week of July, Observing the results of the comet impact firsthand was The Planetary Society sponsored or cosponsored more than the high point of the week for the 800 people who came to 35 events all across the US and around the world-in Cana­ the US Naval Observatory (USNO) on Thursday, July 21. da, Spain, Ireland and Malaysia. David Morrison of NASA When we announced our plans for this in June, the free Ames Research Center, Donald Yeomans of the Jet Propul­ passes were immediately snapped up, and the event quickly sion Laboratory and David Levy were among our lecturers. became one of the hottest tickets in Washington. The pro­ In Los Angeles on July 16, the frrst night of the impacts, gram and open house were jointly sponsored by the obser­ Mount Wilson's 100-inch telescope was connected to sev­ vatory and by the Society. eral television monitors so that the 300 event-goers could July 21 did not begin auspiciously for an outdoor event. watch as the comet fragments struck Jupiter. About 40 In midaftemoon the first raindrops spattered the pavement, amateur astronomers brought their telescopes and trained and weather forecasts warned of a tropical depression mov­ them on the planet. The fragments that hit the first night ing into the region. By 6:00 p.m. it was pouring at the Naval were among the smaller ones, and a light cloud cover Observatory, but the sky did clear long enough for everyone moved in just after dusk, so, unfortunately, those attending there to catch a glimpse of Jupiter. The observatory's 12- the event were not able to see any sign of the impacts. inch and 26-inch telescopes were opened to the public, and One night during the impact period, at the Museum of local amateur astronomy groups provided a few dozen addi­ Science in Boston, approximately 500 people "lasted all tional telescopes for the evening. These telescopes were night long," according to Planetary Society Regional Coor­ scattered across the sloping lawn of Vice President Gore's dinator Regina Forbes-Schraut, to see the dark marks left by helicopter pad (his residence is located on USNO grounds). the impacts. Interest was so high in Galway City, Ireland, Fortunately, for the sake of continued amateur astronomy that about 300 people crowded into a theater built to seat in the region, only fireflies flew over the helipad that night. 100 to hear a lecture on the comet by physicist/astronomer David Levy, one of our speakers, got his first chance to Kevin Nolan. Ireland Regional Coordinator Paul Bracken actually see the comet impact sites that night. Once he reports that the lecture was so well received the audience peered through the observatory's l2-inch telescope and wanted more, and he got numerous requests for a second began to sketch Jupiter, no one could tear him away until lecture to present post-impact data and analysis. . the clouds returned. All in all, this part of Jupiter Watch has been a great suc­ Other speakers included Christopher Chyba, who talked cess. We now look forward to keeping the public interest in about the Tunguska explosion in 1908, and Ken Johnston, planets and comets high. Our next target date is December scientific director of US NO. 7, 1995, when the Galileo probe will enter Jupiter's atmo­ On July 22, we wrapped up a spectacular week of comet sphere and the spacecraft will go into orbit about the planet. impacts with a presentation by Planetary Society President More Jupiter Watch events and programs are corning, and Carl Sagan, David Levy and the Shoemakers to a thousand we'll let you know what's going on when our plans are set. people at the Stouffer Mayflower Hotel. Tired but ecstatic, Levy and the Shoemakers traced the story of the comet's Susan Lendroth is Manager ofEvents, and Carlos J. Populus discovery through its fiery demise, while Sagan discussed is Volunteer Coordinator, for The Planetary Society. 15 and

by Clark R. Chaplnan

fthe energy of the excited state of year's issue is on life in the universe; numerous books, and argues that many carbon 12 were just a little higher, predictably, it contains articles like of our cherished beliefs about ourselves I the processes that create heavy Leslie Orgel's essay on the origin of are, at best, distorted. Far from living in elements in stellar interiors would fail life. But the table of contents ranges the "age of man," human beings are a to form carbon. The universe would then from the Big Bang (and the eventual marginal evolutionary accident within be made of just hydrogen and helium, "Big Crunch" or "Big Chill"), through an interminable "age of bacteria." Gould without the ingredients for life. So writes the creation of the elements and the shows that life has evolved episodically, physicist Steven Weinberg in the development of Earth' s atmosphere, to that it has hardly "progressed" in diver­ October issue of Scientific American. the nature of intelligence itself. In short, sity and complexity, and that we are a The prevalence ofmarnmals (and the this topic embraces physics, chemistry, special product of evolution only in a neurologically complex species Homo geology and biology-with a fair chauvinistic sense that we ourselves sapiens) on Earth is but the quirky out­ amount of philosophy tossed in, too. appreciate. come of a bewildering sequence of On one level, the October Scientific chancy events during the past billion American is a primer on modem think­ Planets as years. Otherwise, dinosaurs might still ing about how stars formed and how life Abodes of Life reign-or evolved algal mats might be evolved, illustrated by recent pictures Missing from the October Scientific the most complex life-form on our from the Hubble Space Telescope. On American is an article about planets. planet. So argues Stephen Jay Gould, another level, it serves as a launching (Carl Sagan's piece concerns planets, also in the October Scientific American. pad for the reader's own personal explo­ but he rarely strays from his topic of Indeed, were it not for the wild tem­ ration of what his or her mind can learn searching for life.) Another odd thing perature oscillations of recent ice ages, about itself and its origins. about the universe is that it naturally our brains might not have been stimu­ creates the local concentrations of heavy lated to develop language and intelligence, Certainties and elements we call planets, and places according to William Calvin. More Uncertainties some of them in propitious locations recent ups and downs in the success of The astrophysicists who wrote the (in swarms of carbonaceous projectiles different societies around the world, introductory articles in this collection near stars), where their surfaces can discussed by Robert Kates, have put me seem confident about what happened reach room temperature, so that water (and you. my readers) in an advantaged during the first minute (indeed the first is liquid and can mediate chemical reac­ culture where we can read Scientific millionth of a millionth of a second!) tions involving the organic materials American or The Planetary Report. of the universe's existence. And they that rain from the skies. That is a recipe Otherwise, we wouldn't now be contem­ are sure about how the heavens came for an abode for the origin and suste­ plating these questions. to look the way they do and how the nance oflife. chemical elements came to be. Yet one must piece together scattered The Anthropic Principle Later articles carry a much less cer­ paragraphs from several articles to learn Perhaps the contingencies that led me to tain tone (or ought to). Claude Allegre the rudiments of planetary formation, the write these words, and you to read them, and Stephen Schneider describe the life cycle of planets, and the modulation just manifest the anthropic principle: If conflicting theories about how Earth's of environments caused by planetary things had happened differently (as in a atmosphere evolved. Calvin's article on processes. The articles leap too quickly trillion parallel universes), we wouldn't how intelligence emerged sounds con­ from stars to the evolution oflife on be here to witness, or ask about, our uni­ vincing, but Marvin Minsky's very dif­ Earth. But that is a small criticism of verse. Maybe there are as-yet-unknown ferent perspective on intelligence makes an otherwise excellent source of after­ laws of physics that will explain the seem­ one wonder if we really know enough dinner reading material. ing coincidences. Perhaps a Gaia-like about our brains to know why we are process operates, in which life modifies intelligent. Clark R. Chapman has been named a and stabilizes its environment to foster Best of all is Stephen Jay Gould's member of the imaging/spectroscopy evolutionary progress. But maybe not. article on evolution. He integrates all team ofNASA's first Discovery mission. Each autumn, Scientific American the threads he has woven in his writings the Near Earth Asteroid Rendezvous 16 devotes an issue to a single topic. This for Natural History magazine and his (NEAR) . World lNatch

Planetary Society Vice President Bruce derstanding and cooperation with the the 21st century. Japan may also partici­ Murray recently completed a three-month world, we will strengthen our efforts in pate in the international projects for geo­ stint at the Institute of Space and Astro­ space development as follows. logical surveys of the Moon and other nautical Science (ISAS) in Japan. There 1. Actively address such tasks as planets using multipoint observation and he provided input to ISAS and others exploring the unknown universe and rovers. on possible future missions and space further deepening understanding about In the third decade of the 21st century, opportunities. the Earth as the foundation for the future targets of observation will be expanded ISAS is Japan's principal organization of mankind. to the outer edge of the solar system. responsible for space science and plane­ 2. Try to positively develop creative The l)1edium-sized satellite programs tary exploration. The larger National and innovative space technologies that will be continued, and a new lnnar and Space Development Agency (NASDA) is may be inherited by the next generation, planetary program using large launch that nation's main space agency, respon­ for the purpose of enlarging the sphere vehicles may be pursued within the sible for developing its space infrastruc­ of human activities in space. framework of international cooperation. ture, human spaceflight program and 3. Make efforts to ensure that the phi­ Japan will continuously promote un­ Earth applications. Japan has absolute­ losophy and significance of space develop­ manned lunar exploration in order to in­ ly no military space program, consistent ment can be shared internationally in or­ vestigate the possibilities of conducting with its constitution and pacifist political der to promote international cooperation. space activities on the Moon. views. Solar system science using medium­ For two purposes, lunar scientific Overseeing the entire Japanese space sized observation satellites in Earth orbit exploration and possible lunar usage, program is the Space Activities Commis­ and space probes will be enhanced to in­ NASDA, ISAS and other space science sion (SAC). It has just produced a new crease our understanding of the Earth's research institutes will promote unmanned government policy document, "Toward atmosphere and plasma environment programs: First phase: Lunar observa­ Creation ofa Space Age in the New which will be extended to the research tion by satellites in lunar orbit. Second Century;" outlining Japan's vision for of the atmospheres of Venus and Mars. phase: Lunar surface observation using space over the next three decades. This [Planet-B, a Mars aeronomy orbiter, will landers and rovers. Third phase: Return­ coherent plan displays a strong interna­ launch in 1998.] Studies of the Moon's ing samples from the lunar surface. tional focus. internal structure will also be conducted In and after 2010, it is conceivable Japan has set a course to become a and their results will be used primarily that lunar activities will be conducted major player in Earth's exploration of as the basis for studying the internal through international cooperation. These the solar system. We print here a few structure of other planets such as Mars. activities may include such as the con­ excerptsfrom the SAC document. [Seismometers will be carried on the struction of an unmanned observation - Louis D. Friedman surface penetrators of Lunar-A, an and experiment system on the Moon (an orbiter mission scheduled for launch astronomical observatory, etc.) to realize apan is now in a position to make in 1997.] In addition, samples will be continuous unmanned scientific obser­ J effective use of its capabilities to returned from asteroids and comets. [A vation from the lunar surface and Moon progress further in worldwide space sample-return mission to the asteroid utilization experiments. activities. Growing expectations from Nereus is under study for 2003 .] Through Also in the third decade ofthe 21 st Asia-Pacific countries in recent years of these research activities, Japan will century, assuming the development and Japan's role in the field of Earth obser­ accumulate the knowledge to solve the operation of the space infrastructures vation are closely related to the progress mystery of the structure of the solar sys­ enabling highly reliable low-cost manned of Japan's space technologies. tem, its evolution and the origin of life. transportation, it might be possible to In Japan, space development must be In addition to medium-sized satellite construct a manned astronomical obser­ promoted as an important national poli­ programs, Japan will initiate programs vatory on the Moon through interna­ cy. Holding strictly to the principle of utilizing larger launch vehicles to study tional cooperation after determining limiting space development to peaceful Mercury, the Sun, and the outer planets that manned activities are sufficiently purposes, while deepening mutual un- and their satellites in the first decade of justified. D 1 7 for kids in the middle grades. This splen­ didly illustrated-with photographs and Readers' diagrams-account includes a description of the Oort cloud, as well as close-ups of meteorites from Antarctica, and an Service asteroid named Gaspra photographed in space by the Galileo spacecraft in 1991. And for the littlest folk who cuddle on your lap while you watch the news, we suggest Space Vehicles by Anne Rockwell and David Brion. This is a very simple explanation of rockets, probes, satellites, ur Readers' Service is an easy way through adult, is a whole library of infor­ modules, rovers and shuttles, even a future for Society members to obtain newly mation. It includes more than 20 short space station. It features whimsical illus­ Opublished books about the science films, over 400 reference entries, maps of . trations, in paint-box colors, of not people and adventure of voyages to other worlds, the night skies and animated characters but kittens, as the astro-cats that maneuver We make these books available at the who ask and answer the kinds of ques­ these contraptions through space. lowest possible prices, Each title is offered for tions kids ask-such as "Where did the -Reviewed by Bettyann Kevles six months, or three issues of The Planetary Moon come from?" and "How can we Report, We keep rotating our stock so that get there from here?" Still Available: the titles we offer are always fresh, Planetary Society members- young Moon Shot: The Inside and still-young-can design a robot for a , Story of America's mission to Mars, and figure out when to Race to the Moon Space Adventure" send it, what it will do when it gets there By Alan Shepard and Deke Slayton. (CD-ROM), and how to test it before it goes. Then, The story of Apollo and the early days of Knowledge Adventure, 1994. when it's ready, they can watch it hurtle the space program as told by two of the Retail price: $79.95 through space on the computer monitor original Mercury Seven astronauts. Member price: $49.95 to see if it really works. (Reviewed July/August 1994.) On birthdays, youngsters can see how Retail price: $21.95 Contets, Meteors, and the sky looked from anywhere on Earth Member price: $19.00 Asteroids (their hometown, the White House or by Seymour Simon; Down Under in the southern hemisphere) The Making of a Soviet Morrow Junior Books, New York, 1994. on the night they were born. Scientist: My Adventures Retail price: $15.00 And kids who had to be in bed on those in Nuclear Fusion and Member price: $12.00 July nights when comet Shoemaker-Levy Space From Stalin to 9 was breaking apart can see the spectacle Star Wars Space Vehicles re-created as the fragments of the comet By Roald Z. Sagdeev. A chronicle of by Anne Rockwell and David Brion; hit Jupiter in their alphabetical glory. science and politics in the Soviet Union Dutton Children's Books, New York, 1994. If looking up gets boring, they can during the Cold War years. Retail price: $13.99 probe the secrets of planet Earth. Space (Reviewed September/October 1994.) Member price: $11.00 Adve,nture II includes the data NASA Retail price: $24.95 used to discover the ruins of the ancient Member price: $22.00 city of Ubar, which had remained hid­ omputers are already ubiquitous. den for thousands of years beneath the To Place Your Order: C Whether a child rushes to log on Sahara's sands. Please send a check or money order, made to the computer or heads for the book­ But in some important ways CD-ROM out to The Planetary Society, for the price of case depends on what that child needs for cannot compete with books. The pleasure the book (in US dollars) plus, for each book, intellectual and emotional fuel, and on of holding a book is simply different from a shipping and handling charge of $3,00 for what he or she finds in both places. the pleasure of sitting at a keyboard and the US, Canada and Mexico, $6.50 for other It is too soon to know if CD-ROM will using a mouse. No computer can replace countries. Address your envelope to Readers' steal customers from booksellers. But if the joy oftuming pages and perhaps pull­ Service, 65 North Catalina Avenue, Pasadena, you fear for the future of literacy, relax. ing paper tabs. No monitor can be hidden CA 91106-2301. Not only do kids have to read to get to the beneath the bedcovers when the lights go For faster service, order by telephone with heart of Knowledge Adventure's Space out, and there is no portable CD-ROM your Visa , MasterCard or American Express Adventure II, but a child on the cusp of (not yet) to carry outside into the night to card, Call (818) 793-1675 from 9:00 a,m, to literacy can go over the top by following check on the phase of the Moon. 5:00 p.m. Pacific time, the printed text on the screen while listen­ These delights belong to books. And, All books sent postpaid, Please allow 4 to ing to it being read aloud. for the holidays, we recommend Seymour 6 weeks for delivery in the US, Canada and 18 Space Adventure II, for ages eight Simon's Comets, Meteors, and Asteroids, Mexico, 12 weeks for delivery to other countries. Society Ne1NS

Wanted: Today's Heroes Mars Rover to Explore Havvaiian Volcano of Mars Exploration in Next Series of Telepresence Tests The Planetary Society is seeking nomi­ nees for the second annual Thomas O. he Russian Mars Rover is set to been tested on Mars-like terrain in Paine Memorial Award for the Advance­ T roll across the volcanic landscape Death Valley and Kamchatka. ment of Human Exploration of Mars. of Hawaii. On February 27 through Planetary Society members are in­ The award-a memorial plaque, the March 11, 1995, the rover-similar to vited to visit the test site and see the Mars flag and a possible cash prize­ the robotic vehicle under development team in action. The Society is also recognizes those who make noteworthy for Mars '98- is scheduled to prowl planning a number of other events in achievements in the pursuit of the hu­ around Hawaii's Mount Kilauea. Hawaii for this time. For more informa­ man exploration of Mars. (The cash In cooperation with scientists and tion, write to me at Planetary Society award might be presented in cases engineers from Russia, NASA Ames headquarters, 65 North Catalina Av­ where the award selection committee Research Center, McDonnell Douglas enue, Pasadena, CA 91106-2301 , or feels it can assist work that advances and the Jason Foundation, The Planetary call (818) 793-5100. Mars exploration.) Society will participate in this series - Susan Lendroth, Manager ofEvents The deadline for nominations is De­ of robotics tests. The rover has already and Communications cember 30, 1994. Applications must be submitted on an official application form. For a copy ofthis form and nomination procedures, write or call Society head­ and the search for extraterrestrial life. More Apollo Memories quarters. -Charlene MAnderson, This past summer, Richard Weisman On July 20, 1994, President Bill Clinton Director ofPublications of Seattle, Washington, became commit­ and Vice President Al Gore led a White tee chairman. Through his efforts, 68 House ceremony commemorating the NSTA Meeting Features members have joined and donated ap­ 25th anniversary of the Apollo 11 lunar a Day for the Planets proximately $50,000 to the Society. landing. Astronauts Neil Armstrong, Buzz Once again The Planetary Society will The New Millennium Committee was Aldrin and Michael Collins attended, join forces with the National Science formed in 1982 to establish a support along with many other Apollo veterans. Teachers Association to cosponsor the as­ group ofleaders within the Society. Under Among the government and space leaders sociation's annual convention, to be held founding chairman David Brown, presi­ attending this celebration were Planetary March 23 to 26, 1995, in Philadelphia. dent of Time Energy Systems in Houston, Society Directors Carl Sagan, Louis Join us on Planetary Society Day, Texas, the committee has helped advance Friedman and Norm Augustine. March 25, for exciting presentations by several ambitious scientific and educa­ Earlier that day, Aldrin spoke before planetary scientists such as Christopher tional activities and has donated close to members of Congress at a breakfast McKay, winner of the 1993 Paine $300,000 toward scholarships, asteroid sponsored by Spaceweek, the National Award for the Advancement of Human detection, the search for extraterrestrial Space Society and Women in Aerospace. Exploration of Mars; Adriana Ocampo, intelligence and international cooperation Aldrin asserted that humans are about to leader of the Society's geological expe­ in planetary exploration. The Society is take the next step outward- to Mars. dition to Belize in January; and Steven deeply indebted to Brown, Weisman and -CMA Dick, a science historian at the United other members of this group, including States Naval Observatory who writes Steven Spielberg, whose $100,000 dona­ frequently about the search for extra­ tion launched the Megachannel Extra­ terrestrial life. For information and a terrestrial Assay in 1985; George Awad Keep in Touch registration packet, contact Susan of New York City; Polly Brooks of Tucson, Lendroth at Society headquarters. -SL Arizona; Emmanuel Cashell of Sydney, Our mailing address: Australia; and Abe Gomel of Montreal, The Planetary Society Society Members Reach Canada. 65 North Catalina Avenue for the Nevv Millennium For information on how you can join Pasadena, CA 91106-2301 The Planetary Society is expanding its the New Millennium Committee, please General calls: (818) 793-5100 New Millennium Committee. The mem­ contact Richard Weisman or Diana Mar­ bers ofthis group work to advance long­ quez at Society headquarters.-Diana Sales calls only: (818) 793-1675 range projects in planetary exploration Marquez, Director ofDevelopment 19 Questions and AnslNers

If there is no gravity in space, yet the moves in a particular direction, rather were freely falling, then we would be Sun's gravity holds the planets than just any direction, which is speed.) said to have no weight. around it, why don't spacecraft like For a spacecraft launched from this Weight should not be confused with the Voyagers fall in toward it? planet, the initial velocity is Earth's mass, which is an intrinsic property of -Thomas Ramsey (age 11), orbital velocity plus the launch veloci­ all objects. The amount of matter an Emery, Utah ty. Earth's velocity is what puts the object contains is its mass. Even when spacecraft on the curved elliptical they are freely falling, objects have The Voyagers do fall in toward the path. If we could cancel out all that mass. Sun. So do all spacecraft and planets initial orbital velocity, then the space­ -LOUIS D. FRIEDMAN, in solar orbit. The orbit is the "free craft's path would be a straight line Executive Director fall" path that bodies take when acted into the Sun. upon by gravity alone. It is not correct The misunderstanding about there If we were to design a robotic inter­ to say there is no gravity in space. By being no gravity in space may have stellar mission to travel to the nearest definition, the gravitational influence come from the vernacular use ofthe , star system, what is the shortest time ofthe Sun extends throughout the en­ word "weightless" applied to an object in which such a mission could be ac­ tire solar system. It is this gravitation­ that is in free fall. What "weightless" complished using current propulsion al force that keeps the planets and the really means is that no force counter­ technology? spacecraft on their elliptical orbits. acting the gravity is being expended Also, what is the greatest speed the The size and shape of the elliptical - for example the force of Earth's spacecraft would attain? (The mission orbits are detennined by the initial surface, which holds us up and causes could be designed to take advantage velocity and position of the spacecraft. us to have a weight when we rest on ofgravitational assists.) (Velocity is the rate at which an object it. If there were no surface and we - Teal Cooper, Dallas, Texas

Astronaut Loren J. Shriver is having a snack on board the space shuttle Atlantis as it orbits Earth. Away from the force of Earth's surface, these little chocolate asteroids are on a free fall path through space. Photograph: NASA

20 r The nearest star system, Alpha constant. The seasons occur be­ Centauri, is 4.3 light-years, or 4 cause the direction the axis points Factinos trillion kilometers (2.5 trillion is fixed. Earth's axis always points miles), away. Jet Propulsion Labo­ in the general direction of Polaris, ratory engineers have estimated the North Star, which is why the Slight temperature differences in the two comet­ that currently available electrical star is a useful navigation aid in forming regions ofthe solar system cause comets thrusters powered by large nuclear­ the northern hemisphere. During to form in different ways, say NASA researchers. electric power plants might be able summer there, Polaris lies in the "We predict that comets from the Kuiper belt and to get a small robotic spacecraft up direction of the Sun, so the north­ Oort cloud contain structurally different forms of to a speed of 150 kilometers (90 ern hemisphere is bathed in sun­ water ice," say Peter Jenniskens and David Blake miles) per second or 0.05 percent light. During winter, when Earth at NASA Ames Research Center in Moffett of the speed oflight. (Gravitational has moved halfway around its Field, California. assists will not improve that speed orbit, Polaris lies in the opposite According to the researchers, Kuiper belt comets, significantly.) At 150 kilometers direction from the Sun. from the outer region of the solar system beyond per second, it will take 8,600 years Although the tilt of Earth's axis Pluto's orbit, probably formed at temperatures to reach the nearest star system. is constant over a year, it does colder than minus 220 degrees Celsius (minus If we use physically feasible undergo slow modification due to 370 degrees Fahrenheit). Oort cloud comets, but not currently available tech­ the gravitational pull of the other most likely formed in the Neptune-Uranus re­ nology, in the form of powerful planets. These small variations gion and then expelled to much greater distances Sun-pumped laser beams pushing are thought to have caused the ice from the Sun, probably took shape at tempera­ very small robotic probes, it is ages on Earth. If Earth tilts a little tures warmer than minus 195 degrees Celsius conceivable that speeds approach­ closer toward the Sun, then the (minus 320 degrees Fahrenheit). ing 1 to 5 percent of the speed of poles receive more sunlight in Jenniskens and Blake's predictions are based light could be attained, and the summer and vice versa. It is still on laboratory simulations of cometary ice probe would reach Alpha Centauri not clear why our planet's climate formation under conditions thought to exist in the lifetime of the humans who is so sensitive to these small when the objects formed. sent it.The real challenge would be changes in tilt (about 2 degrees) ~from NASA Ames Research Center to design a probe that weighs only that occur over about 40,000 a few grams, yet can send pictures years. Earth's orbit about the Sun Ken Edgett, a planetary scientist from Arizona back over interstellar distances. is elliptical and the shape of the State University, has discovered two types of ~ROBERTL. FORWARD, orbit also undergoes a slow change sand dunes on Mars that are common on Earth. Forward Unlimited over about 100,000 years, which After poring over Viking images, Edgett has also contributes to the ice ages. finally found star dunes and linear dunes. Is Earth the only planet in the Mars' obliquity does fluctuate, On Earth these dunes form in response to solar system whose axial tilt varying through a range of 25 changing weather. Winds that blow from all changes several degrees to cause degrees, but this also takes place directions equally tend to form star-shaped dunes, the seasons? Ifso, why? over lOO,OOO years. It is only the while winds that alternate between two main ~Greg P. Goethel, presence of the Moon that keeps directions create linear dunes. Edgett's discovery Los Angeles, California Earth's obliquity relatively stable indicates that, in at least a few places, martian over long periods of time. Without winds are variable in direction, pointing to a Many of the planets rotate every the Moon's stabilizing influence, more complex picture for weather on the Red day about an axis that is tilted sub­ climate changes would have been Planet than planetary scientists previously had. stantially with respect to the plane so severe on our world that some ~from Astronomy in which they revolve around the have questioned the ability oflife Sun during their year. Earth's to have evolved here. Last spring Galileo returned the first image ever obliquity (the angular tilt of its ~BRIAN TOON, recorded of a satellite orbiting an asteroid (see axis) is about 23.5 degrees from NASA Ames Research Center the July/August issue of The Planetary Report). the vertical. Mars' obliquity is about In this sharper new close-up ofIda's moon Dactyl 24 degrees, so the seasons are (see photo at left), features as small as 50 meters much the same on the two planets. (about 165 feet) across are visible on the tiny Venus has hardly any obliquity satellite, which is only 1 kilometer (0.6 mile) in (2.5 degrees). Uranus is tilted over diameter. so far that sometimes its poles Infrared spectra taken by Galileo suggest that almost point directly at the Sun. the moon isn't just a chip gouged from Ida. These The tilted axis of a planet is data show that the surface abundance of the min­ probably due to collisions of the erals pyroxene and olivine on the satellite differs planet with other very large bod­ from that on Ida, says Robert W. Carlson of the ies early in the history of the for­ Jet Propulsion Laboratory. However, Michael mation of the planet. A collision IS. Belton ofthe Kitt Peak National Observatory between Earth and a Mars-sized in Tucson, Arizona, says that both the asteroid object probably created the Moon, and its moon ultimately stem from the breakup setting our obliquity at the same The International Astronomical Union recently of a much larger body that formed the Koronis approved the name "Dactyl" for the tiny moon time. that Galileo discovered orbiting asteroid Ida. asteroid family. the tilt of Earth's axis is nearly Photograph: JPUNASA ~from Science News 21 Two Faces of Mars The History of Earth 22 1/ 2" x 29" poste r. 1 lb. By Wi ll iam K. Hartmann and Ron Miller. #339 $5.00 260 pages (hard cover). 2 lb. #123 $32.00 Meteorites Poster 221/2" x 29" 1 lb . Starsailing: Solar Sails and #328 $9.00 Interstellar Travel By Lou is Friedman. Each copy autographed Solar System Postcards by the author. 146 pages (soft cover) 1 lb. Set of 16 cards. 1 lb. #157 $9.00 #547 $8.00 Planetary Society Note Cards The Starflight Handbook: Set of 16 cards. Envelopes incl uded . 1 lb. A Pioneer's Guide to #544 $10.00 Interstellar Travel By Eugene Mallove and Gregory Matlo ff. 274 pages (hard cover ). 2 lb. #186 $20.00

~C!tw~~ The New Solar System Dance of the Planets Edited by J Kel ly Beatty and Andrew Q.E.D. ed ition. 18M-co mpatible software Chaikin. 326 pages (so ft cover). 4 lb. - requ ires 80x86 CPU. DOS 3X or higher. #180 $21.00 640K RAM. EGA or VGA graphi cs. hard ~{~k~ ~k;, kel;~~~ ,~~,eVl fuVl ~Vl~ drive. math co processor. 3 1/2" disks In the Stream of Stars on ly. 2 lb. Edited by William K. Hartmann. Andrei #715 $175.00 Sokolov. Ron Mill er and Vita ly Myagkov. 183 pages (hard cover). 4 lb. ~~,~ ~~ ,ke~~;Vl~ w;~k "'k~ "l~Vl~b~~ Murmurs of Earth #124 $25.00 Th is two-CD set. playable on any standa rd CD player. also incl udes the The Quest for Comets: Se~;~~~. uh~ ~k;, ~;f~ ~u;~~ ~Vl~ ~k~ book Murmurs of Earth by Carl Sagan and An Explosive Trail of Beauty the Voyager record team. With a CD-ROM and Danger drive. you can di sp lay images on your PC. By David Levy. ~~ble~ (iVl ~k~ S~~~~m~~~/V~~e~~~ Image access ing re qui res IBM-compatible 280 pages (h ard cove r). 2 lb. computer with 640K RAM. Super VGA #140 $21.50 graphics card fo r 640x480. 256 colors. 1~~~ ;"u~ ef "'k~ "l~Vl~b~~ t~re~~ J mu ltisync mon itor and PC -compatib le CD ­ From the Big Bang to Planet X ROM drive. Or Apple Macintosh LC or II By Terence Dickinson . se ri es. with system 6.0.5 or greater an d 151 pages (soft cover) 1 lb. ~e m~k~ ~V~~~eVl~ eVl ~eu~ l;,~ k~~~~! 2 MB ava ilable memory. a 12- or 13-i nch #105 $11.75 color monitor and Macintosh-compatible CD-ROM drive. 3 lb. A Man on the Moon: #725 $54.00 The Voyages of the Apollo Astronauts Where in Space Is Carmen By Andrew Chaikin . Sandiego? 670 pages (ha rd cover). 3 lb. Specify IB M-com pati ble or Macintosh #101 $25.25 computer. IB M-com pati ble version requi res VGA monitor. DOS 3. 1 or highe r Portrait of the Milky Way Solar System Chart and 640K memory. Macintosh version 40" x 27" po ster. 2 lb. 39" x 25" poster. 1 lb. requires 8-bit co lor monitor. system Vitlect~rej #330 $15.00 #338 $6.00 6.0.7 or higher and 4 MB memory with 2500K free. 2 lb. $50.00 Mars Rover Tests Jupiter Watch Poster Solar System in Pictures #750 IBM-Compatible 27 minutes . 2 lb. $15.00 18" x 24". lib. Nine 8" x 10" min i-posters. 1 lb. #751 Macintosh #466 VHS (NTSC-US) #336 $10.00 #682 $5.00 #467 PAL (VHS-Europe) Large Prints Earth and Its Moon Live From . .. Other Worlds 20" x 16" (except #312. 18" x 24" poster. 2 lb . 122 minutes. 2 lb. $27.00 . which is 20" x 19") #318 $8.50 #806 VHS (NTSC-US) 1 lb. $8.00 each The Grand Tour (PAL not available.) #305 Earth Earth at Night 35" x 23" poste r. 1 lb. By Ron Miller and Wil liam K. Hartmann. The Planets #311 Full Moon #308 $6.50 208 pages (soft cover). 2 lb. 56 minutes. 2 lb. $23.00 #312 Moonscape #166 $13.50 #435 VHS (NTSC-US) #315 Earthrise Europe at Night (PAL no longer avai la ble.) #319 Jupiter 24" x 36" poster. 1 lb. Exploring Planetary Worlds #325 Mars #309 $6.50 By David Morrison. Mars & Mercury #332 Saturn 240 pages (hard cover) 2 lb. 60 minutes . 2 lb. $22.00 #333 Eight-Planet Montage North America at Night #111 $29.00 #425 VHS (NTSC-US) #337 Uranus 29" x 22 1/2" poste r. 1 lb. #427 PAL (VHS-Europe) #340 Venus #326 $6.50 The Search for Life in the Universe Blue Planet An Explorer's Guide to Mars Jupiter/Saturn/Uranus Poster Set By Donald Goldsmith and To bi as Owen. 42 minutes. 2 lb. $25.00 40" x 26" poster. 1 lb . Three 22 1/2" x 29" posters. 1 lb. 530 pages (soft cover). 2 lb. #404 VHS (NTSC-US) #505 $6.00 #327 $15.00 #181 $30.00 #405 PAL (VHS-Europe) ~ ~l~Yl~~I" Ifl~k~ r~".f~~~ ~if~' · ~iv~ Jupiter, Saturn, Uranus & n Neptune: The Voyager Missions l)'ttt~~ 15~~Vl~t~~t1 ~~~Ifl ~e fl'i~Yl~'. 30 minutes. 2 lb. $22.00 #415 VHS (NTSC-US) 15~i::~j I'~l~~iv~,. Ifl~~b~ ~v~Yl #417 PAL (VHS-Europe) Planetary Report Binder 2 lb. #545 $12.00 ~cr" l' be"- ~~~~'ll The New Solar System: An Epic Adventure Spacecraft Science Kits 1'~1fl~lflb~1' ~el.J ~ll ~~~~ 60 minutes. 2 lb. $22.00 1 lb. $14.00 each #430 VHS (NTSC-US) #525 Hubble Space Telescope leYl~r ,. ~~ 'l'!'l~Yl~~~I'~ #431 PAL (VHS-Europe) #538 . Magellan #560 Voyager ~e~i~~~ effel" ~we On Robot Wings- #524 Galileo A Flight Thru the Solar System ex~~r~ieYl~l ~~l~Yl~~I" Approximately 35 minutes. 2 lb. $22.00 Hugg-A-Planet #420 VHS (NTSC-US) #526 Earth 2 lb. $15.00 ~~~~ will ~~li~~~ ~v~l'~ #528 Mars 1 lb. $13.50 #422 PAL (VHS-Europe) 'r~~~ ~Yl~~I.J,i~,t Planetary Society Mug 2 lb. #580 $7.00

Planetary Society Pin Astronomy & Space: Comet Shoemaker-Levy 9 1 lb. #670 $3.00 1995 Weekly Calendar and Jupiter Crash ~ A dazzling photograph awaits you each week as you plan 20 ful l-color slides. 1 lb. Planetary Society Key Ring your da ily appo intments. The planner gives you a year of fun 1 lb. #677 $4.75 #203 $6.25 facts, useful information and elegant visions of space. 1 lb. #523 $11.75 A Spacecraft Tour of the Solar Puzzle-A View to Earth System 2 lb. #502 $16.00 ~~e~j~.l V~ltfe! 40 slides with 23-page booklet. 1 lb. Puzzle-Portrait of the Planets 1Stf!J '1"wc Weekl!J C.~leVlt!~ ... , fc... $:1.~(J! #216 $36.00 3 lb. #556 $12.00 Voyager's Mission to Jupiter Magnets 20 slides. 1 lb. 1 lb. $2.50 each #232 $6.25 #549 Moon #550 Earthrise, Apollo 8 Viking 1 and 2 at Mars #551 Aldrin on Moon's Surface 40 slides with sound cassette . 1 lb. #552 Mother Earth #220 $12.50 #554 Saturn Images of Mars #555 Jupiter and One of Its Moons 20 sl ides with 12-page booklet. 1 lb. Science Models #213 $10.00 2 lb. $19.50 each Magellan Reveals Venus #508 Expedition to Mars #509 Expedition to the Stars 40 sl ides with fact sheet and 3-D glasses. 1 lb. Star Theater #217 $15.00 2 lb. #669 $32.00 Impact Craters 20 sl ides with 12-page booklet. 1 lb. Exploring the Universe: 1995 Wall Calendar #212 $17.00 Enjoy full-co lor photographs, space art and great reading F~~--crJt F~jkiCVU on a variety of subjects each month. This 1995 wall Mars T-Shirt calendar is produced by the creators of Astronomy Black. S, M. L. XL. 1 lb. magazine in cooperation with The Planetary Society. 2 lb. &~~~t~cvd~ #530 $18.00 #520 $10.00 15i~t(J~~fSCCkj Project BETA T-Shirt ~~e~j~l V~ltfe! The Impact Catastrophe Black. L, XL. 1 lb. 1Stf!J '1"wc w~ll C.~leVlt!~ ..., fc... $1~.()(J! That Ended the Mesozoic Era #543 $16.00 1 disk. 1 lb. Ski Mars T-Shirt #763 $9.00 Wh ite. S, M, L, XL. 1 lb. #553 $14.00 Mars Balloon T-Shirt Planetary Society Sweatshirt The Planetary System White. S, M, L, XL. 1 lb . Gray S, M, L, XL. 2 lb. 5 disks. 1 lb. Dive Europa T-Shirt #630 $14.00 #664 $21.00 #762 $36.00 Gray. S, M, L, XL. 1 lb. #568 $14.00 Solar System T-Shirt Magellan: White. Ch ildren's S. M, L. 1 lb. Need a catalog? Call 818-793- Highlights of Venus Climb Olympus T-Shirt #668 $12.00 1675, and we'll send you one. 2 disks. 1 lb. White. S. M, L. XL. 1 lb. White. Adults'S, M, L, XL. 1 lb. #761 $18.00 #517 $14.00 #667 $14.00 Use the form bound inside the magazine to order through the mail. For credit ca rd Images of Mars Mars Rover T-Shirt Planetary Society T-Shirt orders, or for more information on the 2 disks. 1 lb. White. S, M, L, XL. 1 lb. Black. S, M, L, XL. 1 lb. items listed on these pages, just phone #760 $18.00 #532 $14.00 #665 $16.00 our sa les office at 818-793-1675. r j I·

o matter how likely it seems, Nwe have never "seen" planets or solar systems like our own around other stars. The lakeshore of a distant planet in orbit around a double star is the setting for "Binary Sunset."

Edwin Faughn is the art director of the Memphis Museum Planetarium in Memphis, Tennessee, where many original multimedia produc­ tions featuring his work have been created and sold to planetariums worldwide. His artwork has also appeared in Sky & Telescope and Astronomy magazines.

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