Scientific American-June 2007
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BREAKING NETWORK LOGJAMS • TRULY 3-D IMAGES Bring Back America’s Prehistoric Beasts JUNE 2007 WWW.SCIAM.COM Did this molecule start life The Mysteries of Anesthesia When It Pays to Be Irrational How Particles Shape the Cosmos COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC. Visit http://avaxhome.ru/blogs/vietmagz for more.. contents june 2007 SCIENTIFIC AMERICAN Volume 296 Number 6 features BIOLOGY 46 IA Simpler Origin for Life BY ROBERT SHAPIRO 46 Molecular Energy-driven networks of small molecules may be more likely seed of life? fi rst steps for life than the commonly held idea of the sudden emergence of large self-replicating molecules such as RNA. MEDICINE 54 ILifting the Fog around Anesthesia BY BEVERLEY A. ORSER Learning why current anesthetics are so potent and sometimes dangerous will lead to a new generation of safer targeted drugs. PARTICLE COSMOLOGY 62 IWhen Fields Collide BY DAVID KAISER The history of particle cosmology shows that science can benefi t from wrenching changes. ECOSYSTEMS 70 IRestoring America’s Big, Wild Animals BY C. JOSH DONLAN Pleistocene rewilding—a proposal to bring back animals that disappeared from North America 13,000 years ago—offers an optimistic agenda for 21st-century conservation. INFORMATION TECHNOLOGY 78 IBreaking Network Logjams BY MICHELLE EFFROS, RALF KOETTER AND MURIEL MÉDARD Network coding could dramatically enhance the effi ciency of communications networks. INNOVATIONS 86 ISeeing Triple BY STUART F. BROWN Anticipated for decades, machines are fi nally displaying objects in three true dimensions. GAME THEORY 90 IThe Traveler’s Dilemma BY KAUSHIK BASU People playing this simple game consistently reject the rational choice. In fact, by acting illogically, they end up reaping a larger reward—an outcome that demands a new kind of formal reasoning. www.sciam.com SCIENTIFIC AMERICAN 5 COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC. Visit http://avaxhome.ru/blogs/vietmagz for more.. SCIENTIFIC AMERICAN Volume 296 Number 6 departments 8 SA Perspectives Serengeti in the Dakotas. 10 How to Contact Us 10 On the Web 20 104 12 Letters 18 50, 100 & 150 Years Ago 20 News Scan 40 Insights New genetic studies, Eric Vilain says, should ■ Planting a better biodiesel. force a rethinking about mixed-sex babies and ■ Fingerprinting individual atoms. gender identity. ■ Meet the Memjet. ■ Less lethal turbines for dams. 96 Working Knowledge ■ Solid-state laser blaster? Optical character recognition fi nds the write type. ■ New fi sh food: psoriasis patients. 98 Reviews ■ Computers can fi nally pass Go. Books on dirt, fl owers, uncertainty, ■ Data Points: Large Hadron Collider. perishable artifacts. Eric Vilain, 40 University of California, Los Angeles columns 39 Skeptic BY MICHAEL SHERMER The inverse square law trumps the law of attraction. 43 Sustainable Developments BY JEFFREY D. SACHS As global warming tightens the availability of water, prepare for forced mass migrations. 102 Anti Gravity BY STEVE MIRSKY Coffee cup full of beans. 104 Ask the Experts How do itches come about? Why is the sun in the middle of the solar system? Cover image and illustration of molecule on preceding page by Ken Eward, BioGrafx; cover photograph of cheetah by Shani; photograph at left by Brad Swonetz, Redux. Scientifi c American (ISSN 0036-8733), published monthly by Scientifi c American, Inc., 415 Madison Avenue, New York, N.Y. 10017-1111. Copyright © 2007 by Scientifi c American, Inc. All rights reserved. No part of this issue may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording for public or private use, or by any information storage or retrieval system, without the prior written permission of the publisher. Periodicals postage paid at New York, N.Y., and at additional mailing offi ces. 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SA Perspectives Serengeti in the Dakotas Some people love science for the crazy ideas, Whether or not cheetahs ever chase pronghorn the ones that transport you beyond the everyday across the continent again, the rewilding concept has grind: black holes, alien life, anything with the word drawn attention to the fact that the loss of biodiver- “quantum.” Others prefer the not-crazy ideas, the sity is not just a problem for the rain forest; it affects practical solutions: zippier computers, 100-mpg less exotic locations, too. The demise of large ani- cars, cures for cureless diseases. mals has thrown entire ecosystems out of balance. So what do you make of an idea like Pleistocene Even if humans decided now to leave these ecosys- rewilding? It manages to be both crazy and not crazy tems alone, they are too far gone to recover on their at the same time. As the article by C. Josh Donlan own. The prairie would revert not to its Pleistocene beginning on page 70 describes, glory but to a scraggly weedland. a team of biologists has pro- Instead of merely bemoaning nature’s plight, the posed a decades-long project to proponents of rewilding are doing something about restock North America with it. The reintroduction of wolves in Yellowstone a de- large mammal species like those cade ago brought the population of moose and elk that roamed the continent be- under control, with a cascade of benefi ts for vegeta- fore humans crossed the Bering tion, birds and beavers. Other projects have reintro- Strait—species such as camels, duced tortoises, bison and falcons into their old lions and elephants (the nearest haunts. Wildlife-stocked private ranches let you go thing to mammoths). The un- on safari within half an hour’s drive of the Alamo. dertaking would culminate More broadly, biologists are also working to restore in a vast national park—1,000 fi sheries, forests and wetlands. square miles or more—stretch- Most of these efforts are too piecemeal to nurse ing across the Great Plains. The whole ecosystems back to health. They need a broad- NOT QUITE a woolly mammoth, plains states are depopulating er framework, and a grand rewilding project can pro- but close. anyway, whereas Africa and vide it. Visionary schemes have a checkered history. Asia are fi lling up. So the project The ones that work combine big ideas with baby would transplant wildlife from where it gets in the steps. They need both: for lack of attention to detail, way to where it would have plenty of room. a grand project can easily fail; equally so, for lack of To be sure, Midwesterners might not see it that an overarching plan, incremental steps can seem like way. Elephant families running free under big skies spitting in the sea. Recent history offers many ex- sounds romantic—unless you have to dodge them on amples of enterprises that, deprived of a real goal, lost your morning commute. Lion cubs are so very cute— their way. One that comes to mind is the human space except when they wander into your backyard. Farm- program. After the moon landings, NASA became ers worry about rampaging rogues, cattle ranchers little more than a delivery van service. about novel diseases. Proponents have addressed A thriving ecosystem can underpin economic some of the concerns but clearly have a lot more prosperity and enhance our quality of life, but it won’t Peter Arnold, Inc. work to do. happen on its own. We have to make it happen. DONA THE EDITORS [email protected] 8 SCIENTIFIC AMERICAN JUNE 2007 COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC. Visit http://avaxhome.ru/blogs/vietmagz for more.. 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