The On the Cover: Volume XVIII Deer fihd repose in a bucolic alpine meadow nestled in Olympic Table of National Park. But such scenes of seeming security and timeless­ Number 3 ness are illusory-as the dinosaurs discovered 65 million years May/June 1998 ago when.a comet or asteroid impact wiped them out Earth Contents resides in a swarm of smaller bodies, many with the potential to wreak havoc on civilization. We have discovered about 10 percent of the near-Earth objects, but one of th e many unknown objects may at any time appear and pass through our ne ighborhood- Features as did comet Hyakutake just last year. Such as-yet -undiscovered Opinion: co mets may pose the greatest danger to life as we know it. 4 The Green Space Project Deer photo: J. Lotter, Tom Stack & Associates To many of us, an alliance of our forces with those ofthe environmental movement has Comet Hyakutake: Johnny Horne seemed a natural thing to create. But not everyone feels that way. Noted science fiction author and Planetary Society member Kim Stanley Robinson explores this dilemma. 6 Deep Space 1: FroID Exploration Technology for the 21 st Century "Faster, better, cheaper" is the new and unofficial motto of NASA. The agency's New The Millennium program is soon to test the effectiveness of that motto in guiding technology Editor development with the launch of Deep Space 1. 9 The Mars Rock: SOlne of Its Chelnistry Is Froln Earth t may not be explicit, but there is a theme In August 1996 the announcement that scientists from NASA and Stanford University had I running through this issue: life on Earth found possible traces of ancient life on Mars touched off a flurry of experimentation and and its relationship to chunks of ice and controversy. Here is a report on two recent studies that question the original findings. rock from space. In 1980, as the Planetary Society was getting off the ground, Luis and '0 Earthly Contalninants Walter Alvarez and colleagues published Don't Rule Out Martian Life their hypothesis that an asteroid or comet Members of the team that found the putative traces of ancient Martian life believe that their impact 65 million years ago triggered the argument has grown stronger over the past year and a half. Here they counter the recent extinction of the dinosaurs. With that paper, studies questioning their evidence and its interpretation. they helped solve a scientific mystery of long standing. '2 Deep IlTIpact: They also changed humanity's perception Fillning a Coslnic Catastrophe oflife and its relation to the heavens. The In this magazine we don't usually report on films, but Deep Impact explores some ofthe evolutionary process that shaped our hands topics we cover regularly. When we were given the opportunity to review the script, we and brains was itself shaped by things decided to share our analysis of the producers' efforts with Planetary Society members. falling from the sky. Life's earthly environ­ ment, after this recognition, can no longer Departments be seen as separate from the larger environ­ ments of the solar system, the galaxy, and, 3 Melnbers' Dialogue ultimately, the universe. And in this intellectual environment, '6 The Stuff of Life the Planetary Society has thrived. We've focused many of our programs and projects , B Ne\Ns and Revie\Ns on asteroids and comets, especially those that orbit in the same solar neighborhood as , 9 World Watch Earth. They may be small in size, but their importance cannot now be underestimated. 20 Questions and Ans\Ners Relatively few people outside the scien­ 22 Society Ne\Ns tific community and the Planetary Society fully appreciate our relationship to these small visitors. Recent headlines and even Contact Us Hollywood movies notwithstanding, we have a lot of work to do to raise public Mailing Address: The Planetary Society, 65 No rth Catalina Avenue, Pasadena, CA 91106-2301 awareness of our true place in space. General Calls: 626-793-5100 Sales Calls Only: 626-793-1675 -Charlene M. Anderson E-mail: [email protected] World Wide Web Home Page: http://planetary.org The Planetary Report (ISSN 0736-3680) is published bimonthly at the editorial offices of the Planetary Society, 65 North Catalina Avenue, Pasadena, CA 91106-2301,626-793-5100. It is available to members of the Planetary Society. Annual dues in the US are $25 (US dollars); in Canada, $35 (Canadian dollars). Dues in other countries are $40 (US dollars). Printed in USA. Third-class postage at Pasadena, Ca lifornia, and at an additional mailing office. Canada Post Agreement Number 87424. A Publication of Editor. CHARLENE M . ANDERSON Technical Editor, JAMES O. BURKE Associate Editor, DONNA ESCANDON STEVENS Copy Editor, KARL STULL THE-P'::'A~T1RV SOCIETV Assistant Editor, JENNIFER VAUGHN Proofreader, LOIS SMITH Production Editor, WILLIAM MCGOVERN Art Director. BARBARA S. SMITH o .~-e- cp -& 0 Viewpoints expressed in columns or editorials are those of the authors and do not necessarily represent pos itions of the Planetary Society, its officers, or advisors. © 1998 by the Planetary Society. o Co-founder CARL SAGAN Members' 1934·1996 Board of Directors BRUCE MURRAY Dialogue President l Professor of Planetary Science and Geology, Galifornia Institute of Technology LAUREL L. WILKENING Vice President Chanceltor, University of California, !Nine LOUIS D. FRIEDMAN ExecutiveOireclor NORMAN R. AUGUSTINE Chairman and CEO, Lockheed Martin Corporation ANN DRUYAN Shiva hTipact events as acid rain and impact you use metrics in the body of your author and producer I appreciate your excursion (see winter following the KIT impact articles for those with "deeper DONALD J. KUTYNA "The Shiva Hypothesis: Impacts, fade when compared to the actual interests," whatever that means, former Commander, US Space Command JOSEPH RYAN Mass Extinctions, and the Galaxy" vertebrate record. Aquatic species and footnote "old terms" (imperial) Executive Vice President and General Counsel, Marriott International in the January/February 1998 issue would have been hardest hit by - I guess that implies shallow ROALD Z. SAGDEEV tolmer Director, Institute for Space Research. of Th e Planetary Report) beyond acid rain, yet most (75 percent of interest? As a former Mercury, Russian Academy of Sciences the usual mission planning/mission 49 species) survived the KIT Gemini, and Apollo worker keenly STEVEN SPIELBERG results focus of The Planetary boundary. Similarly, ectothermic interested in space exploration but, director and producer KATHRYN D. SULLIVAN Report. Until reading that article vertebrates should have succumbed alas, an "old term" imperial "lay­ President and CEO, Ohio's Center of Science and Industry I had not realized that there have to impact winter, yet they too did person," I nonetheless think Bath and former astronaut NEIL TYSON been many mass extinctions of well (66 percent of 61 species). hit on a great idea when he (or Director, Hayden Planetarium, terrestrial life forms in our history. During the KIT interval we also she) said 1,000 and 2,250 degrees American Museum of Natural History That these extinctions appear to have one of the greatest sequences Fahrenheit to laypeople was just Advisory Council JOHN M. LOGSDON occur cyclically is most sobering­ of volcanic eruptions in Earth's "damned hot." Right on! Chairman Director, Space Policy Institute, the projectiles for the next bombard­ history (the Deccan Traps in India) But I propose we take Bath's George Washington University ment are, likely, on their way. and the largest loss of epicontinen­ great idea further-make every­ DIANE ACKERMAN - RON PATE, Toronto, Canada tal seas and accompanying coastal body happy and footnote both poet and author BUZZ ALDRIN habitats in the past 250 million metric and imperial measurements Apollo 11 astronaut RICHARD BERENDZEN Michael R. Rampino is correct in years. Thus, the KIT impact takes and for the article body coin new educator and astrophysicist stating that the idea of periodicity its place, along with several other measurements we all understand. JACQUES BLAMONT Chief SCientist, of mass extinction and impacts is likely causes, as a necessary, but For example, as D. T. suggested, Cenlte Natronal d'Etudes Spatiales, France controversial. In his discussion of not sufficient, cause of extinctions use "damned hot" and call it DH RAY BRADBURY poet and author the extinction at the Cretaceous/ at the end of the Cretaceous. for anything, say, over boiling; DAVID BRIN Tertiary (KIT) boundary, however, - J. DAVID ARCHIBALD, anything over 500 miles (? kilo­ author ARTHUR C. CLARKE he makes statements that are either San Diego, California meters) DF (damned far); less author out-of-date, incorrect, or have no than a second, DQ (damned quick). CORNELIS DE JAGER Professor of Space Research, The Astronomical published data supporting them. Ejecta from the Chicxulub crater You get the idea. Institute al Utrech/. the Netherlands First is the size of Chicxulub. (with a documented rim diameter - CARL L.WOLARY JR. , FRANK DRAKE President, SETf Instilule; Professor of Astronomy and Astrophysics, The most recent estimates place it of 180 kilometers, or 112 miles) Oviedo, Florida University of Galifornla, Santa Cruz at 100 kilometers (62 miles) across, mark the KIT boundary worldwide. STEPHEN JAY GOULD Alexander Agassiz Professor of Zoology, not 200 kilometers (see the Novem­ Archibald quotes the diameter of By using both metric and English Harvard University ber 20, 1997 issue of Nature). If the initial cavity formed on impact, units you are being fair to all of SHIRLEY M. HUfSTEDLER educator and jurist this impact was such a killer, why which quickly expands into the much your readers. Moreover, placing GARRY E. HUNT did the Late Eocene, comparably­ larger final crater. The smaller the two systems' values side by space SCientist, United Klngdom SERGEI KAPI TSA sized Popigai Crater in Siberia Popigai and Chesapeake craters side actually facilitates the reader's Institute for Physical Problems; and the probably contemporaneous (which produced one-tenth the ener­ comprehension of both systems.