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Spacecraft Do-It-Yourself Satellites Brain Science How Language Shapes Thought February 2011 ScientificAmerican.com Fish Farms A Blue Food Revolution? Scaling Back Obesıty What science says about losing weight and keeping it off PAGE 40 © 2011 Scientific American www.diako.ir You never stop growing.™ Retiring well means different things to different people, but we all Which is why millions of mutual fund investors rely on our strategic help their dreams come true. Talk to your financial advisor about Summary prospectuses, if available, or prospectuses for the Funds containing objectives, risks, charges and expenses, and read the summary prospectus prospectus contain this and other information about the Fund. gsam.com www.diako.ir Untitled-3 1 12/21/10 2:23:16 PM invest with the hope of growing old gracefully. expertise and risk management experience to mutual funds from Goldman Sachs. more information may be obtained from your financial advisor. Please consider a Fund’s and the prospectus carefully before investing. The summary prospectus, and/or the Goldman, Sachs & Co. is the distributor of the Goldman Sachs Funds. ©Goldman, Sachs & Co., 2010. All rights reserved. www.diako.ir Untitled-3 2 12/21/10 2:23:17 PM ON THE COVER If current trends continue, an excess of weight will surpass smoking as the primary cause of preventable deaths in the U.S. Health experts, however, often overlook the best near-term strategy for stopping the obesity epidemic: be- havior-modification methods that have been shown to change people’s eating and exercise habits. February 2011 Volume 304, Number 2 Illustration by Bryan Christie. 78 FEATURES HEALTH influence how they function, in both health and disease. 40 How to Fix the Obesity Crisis By Tom Misteli Although science has revealed a lot about metabolic ECOLOGY processes that influence our weight, the key to success 74 A Friend to Aliens may lie elsewhere. By David H. Freedman Ecologist Mark Davis thinks that his colleagues SPACE exaggerate threats from invasive species. 48 Citizen Satellites Interview by Brendan Borrell Even a small research group can now afford to ASTROPHYSICS send its own science experiments into Earth orbit. 78 X-ray Vision By Alex Soojung-Kim Pang and Bob Twiggs Thanks to amazing mirrors, NASA’s NuSTAR telescope, SUSTAINABILITY scheduled to launch in 2012, will peer past clouds 54 The Blue Food Revolution of dust to reveal hidden phenomena in the cosmos. New fish farms out at sea, and cleaner operations By Fiona Harrison and Charles J. Hailey along the shore, could provide the world with a rich NEUROPROSTHETICS supply of much needed protein. By Sarah Simpson 80 Mind Out of Body COGNITIVE PSYCHOLOGY Brain-wave control of machines will allow the wheel- 62 How Language Shapes Thought chair-bound to walk and portends a future of mind The languages we speak affect our perceptions melds and thought downloads. By Miguel A. L. Nicolelis of the world. By Lera Boroditsky HISTORY OF SCIENCE BIOLOGY 84 Jefferson’s Moose 66 The Inner Life of the Genome Thomas Jefferson waged a second revolution, The way our genes are arrayed and move in the fighting the image created by European naturalists 3-D space of the nucleus turns out to profoundly of a degenerate America. By Lee Dugatkin 2 Scientific American, February 2011 Photograph by Floto + Warner www.diako.ir© 2011 Scientific American Be heard. Hear. The Bose® Bluetooth® headset. Finally, better sound quality for both ends of your calls. Introducing the fi rst Bluetooth headset from Bose that does what others cannot. The Bose Bluetooth headset lets you hear and be heard, even as noise levels change. It is engineered with proprietary technologies, so voices sound the way they should and you can hear what is being said better than ever before. In addition, an exclusive noise-rejecting microphone combined with digital signal processing allows you to be heard even when calling from a noisy environment. By combining advanced design and materials, this headset stays securely and comfortably in place. No other Bluetooth headset offers all this. Experience it for yourself, and discover how much better you can hear, and be heard. To learn more, call 1-800-486-7145, ext. 3108 or visit Bose.com/mobile ©2010 Bose Corporation. Patent rights issued and/or pending. The Bluetooth word mark is a registered trademark owned by Bluetooth SIG, Inc., and any such use by Bose Corporation is under license. www.diako.ir BOS74174_3108.indd 1 10/1/10 2:04:34 PM DEPARTMENTS 6 From the Editor 8 Letters 14 Science Agenda States should eliminate voluntary exemptions from childhood vaccines. By the Editors 16 16 Forum The bright side of science gridlock in Washington. By Francesca Grifo 20 Advances Vitamin D throwdown. Gut worms. Fat cats. A bird-watcher in Baghdad. What we can’t smell. Death by plastic. A magnet for flu. Winter babies. Mystery of the talking particles. Math and popularity. 34 The Science of Health Popular demand for an unproved surgery for MS shows the growing power of social media. By Katie Moisse 38 TechnoFiles The success of Google’s Android software doesn’t prove that open is better. By David Pogue 88 Recommended 30 Bringing prehistory to life. The deadly choices of the antivaccine movement. By Kate Wong 89 Skeptic Houdini’s skeptical advice. By Michael Shermer 90 Anti Gravity Can’t science and art get along? By Steve Mirsky 91 50, 100 & 150 Years Ago 92 Graphic Science Your brain in love. By Mark Fischetti ON THE WEB ) CMS On the Scene at CES 2011 Geek out with our coverage of the gargantuan tech expo, which descends every year on Las Vegas with the latest OLLABORATION ( OLLABORATION in computing and gadgetry. C MS 91 C Go to www.ScientificAmerican.com/feb2011/ces Scientific American (ISSN 0036-8733), Volume 304, Number 2, February 2011, published monthly by Scientific American, a trading name of Nature America, Inc., 75 Varick Street, 9th Floor, New York, N.Y. 10013-1917. Periodicals postage paid at New York, N.Y., and at additional mailing offices. Canada Post International Publications Mail (Canadian Distribution) Sales Agreement No. 40012504. Canadian BN No. 127387652RT; QST No. Q1015332537. Publication Mail Agreement #40012504. Return undeliverable mail to Scientific American, P.O. Box 819, Stn Main, Markham, ON L3P 8A2.Individual Subscription rates: 1 year $39.97 (USD), Canada $49.97 (USD), International THE OF THE BENEFIT FOR , $61 (USD). Institutional Subscription rates: Schools and Public Libraries: 1 year $69 (USD), Canada $74 (USD), International $81 (USD). Businesses and Colleges/Universities: 1 year $299 (USD), Canada $304 (USD), CERN International $311 (USD). Postmaster: Send address changes to Scientific American, Box 3187, Harlan, Iowa 51537.Reprints available: write Reprint Department, Scientific American, 75 Varick Street, 9th Floor, New York, N.Y. 10013-1917; fax: 646-563-7138; [email protected]. Subscription inquiries: U.S. and Canada (800) 333-1199; other (515) 248-7684. Send e-mail to [email protected]. Printed in U.S.A. OPYRIGHT OPYRIGHT Copyright © 2011 by Scientific American, a division of Nature America, Inc. All rights reserved. C 4 Scientific American, February 2011 www.diako.ir© 2011 Scientific American Advancing twisted light applications Now there's an easier Usually we think of light as traveling in a straight path, in a train of parallel planes called wavefronts. But light can also be twisted into helix-shaped way to put a precise spin wavefronts for many useful new applications. on "twisted light" The challenge is how to precisely control the twisting of the light—and do that with equipment that is flexible and widely usable. Hamamatsu created an Special phase profiles elegantly simple solution... (left) twist light into the Their Liquid Crystal on beam patterns at right. Silicon Spatial Light Modulator (LCOS-SLM) uses a computer to precisely shape the reflective profile of a liquid crystal surface. Applying special phase Hamamatsu is opening the new frontiers of Light profiles to that surface will twist the reflected light in precisely controllable ways. Yet the system is compact, cost-efficient and easy to use. Which may help scientists in devel- Hamamatsu's LCOS oping new twisted Spatial Light Modulator light applications... Such as new computers that employ the infinite quantum states of optical vortices to process data. Or new generations of quantum communications and data encryption. Or "optical tweezers" that can manipulate cells and other micro particles... Twisted light: It's another exciting new frontier that Hamamatsu is helping to open! http://jp.hamamatsu.com/en/rd/publication/ Hamamatsu's computer-controlled Liquid Crystal on Silicon Spatial Light Modulator (LCOS-SLM) is able to very precisely convert a straight beam of light into a twisted, helix-shaped beam for use in many advanced applications. www.diako.ir Twisted Light ad.indd 1 12/13/10 12:34:48 PM From the Editor Mariette DiChristina is editor in chief of Scientific American.Find her on Twitter @SAeditorinchief Too Much and Not Enough he growing familiarity of the statistics does lit only the currently available solutions that are best supported by tle to ease the painful realization of how disturb research. What they are may surprise you. Turn to page 40. ing they are. About a third of Americans are over Fish farms, as now practiced along coastlines, have had a con weight, and another third are obese—a jump from troversial role in satisfying our hunger for seafood, given their just 13 percent obese in 1962—and as a nation we track record of problematic environmental practices. With many Tare growing fatter all the time. The excess wild fisheries collapsing from commercial weight has severe consequences.