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NEUROSCIENCE SUSTAINABILITY HEALTH Power of the Can Africa’s Population Ta s t e Re c e p t o r s Infant Brain Rise to Six Bıllion? Fight Disease ScientificAmerican.com FEBRUARY 2016 The Search for Planet X Is it hidden in the solar system’s outer reaches? © 2016 Scientific American FEBRUARY 2016 VOLUME 314, NUMBER 2 44 SPACE SUSTAINABILITY 30 The Search for Planet X 56 Six Billion in Africa A planet larger than Earth may be Population projections for hiding in the far reaches of the solar the continent are alarming. system. By Michael D. Lemonick The solution: empower women. HEALTH By Robert Engelman 38 Bitter Taste Bodyguards NEUROSCIENCE Tongue proteins that sense harsh 64 The Power of foods are sentinels in other body the Infant Brain parts, guarding against disease. The child’s brain undergoes By Robert J. Lee and brief periods of intense change. Noam A. Cohen It might be possible to reinstate SOCIAL BEHAVIOR this malleability later in life 44 Collective Wisdom of Ants to correct neurological and Understanding how ants manage psychiatric disorders. to carry out complex feats By Takao K. Hensch without a leader could lead to improved data networks and ASTRONOMY cancer treatments. 70 My Life as ON THE COVER By Deborah M. Gordon If the solar system is harboring a hidden planet, a Comet Hunter it could be a so-called super Earth, a planet up to ) TECHNOLOGY A leading cosmic sleuth roughly 10 times more massive than Earth. Such 48 The Quantum Hack found his life’s calling while a planet would be too dim and too far to be seen easily by current telescopes, but its gravitational harvester ants harvester Today’s encryption methods trying to pass a French test pull could explain some odd behavior among will soon be obsolete. What then? in high school. other bodies in the distant solar system. ALEX WILD ALEX ( By Tim Folger By David H. Levy Illustration by Ron Miller. February 2016, ScientificAmerican.com 1 © 2016 Scientific American 4 From the Editor 6 Letters 10 Science Agenda Beware the exaggerated claims of fetal genetic tests. By the Editors 11 Forum Without government resources, basic science would grind to a halt. By Nathan Myhrvold 12 Advances The best hope for dark matter detection boots up. A virtual crash test dummy. How jellyfish galaxies 11 are born. The birds that choose love over food. 24 TechnoFiles When will we be able to vote online? By David Pogue 26 The Science of Health Your medical records are for sale. By Adam Tanner 72 Recommended Risking the fury of volcanoes. Superconducting Super Collider failure. How living in homes made us human. By Clara Moskowitz 73 Skeptic Can our minds live forever? By Michael Shermer 12 74 Anti Gravity Public health info has to take into account how the public will interpret it. By Steve Mirsky 75 50, 100 & 150 Years Ago 76 Graphic Science The developing world battles diseases of the rich and poor. By Mark Fischetti ON THE WEB First Footprints on Mars Scientific Americanexamines nasa’s plans to send humans to Mars in the 2030s. Go to www.ScientificAmerican.com/feb2016/mars 72 Scientific American (ISSN 0036-8733), Volume 314, Number 2, February 2016, published monthly by Scientific American, a division of Nature America, Inc., 1 New York Plaza, Suite 4500, New York, N.Y. 10004-1562. 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; TVQ1218059275 TQ0001. 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 $61 (USD). 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Scientific American maintains a strict policy of editorial independence in reporting developments in science to our readers. ENRICO SACCHETTI ( SACCHETTI ENRICO 2 Scientific American, February 2016 © 2016 Scientific American FROM THE EDITOR Mariette DiChristina is editor in chief of Scientific American. Follow her on Twitter @mdichristina quarry in the cloud of objects beyond Neptune known as the Where Is Kuiper belt. Turn to page 30. And if you enjoy quests for objects in the night sky, after that you might jet to page 70 for “My Life as a Comet Hunter,” where David H. Levy describes a “cosmic Planet X? passion” that’s lasted for the past 50 years. In contrast to the expanding universe, Robert Engelman writes, When we look up at the night sky, it’s easy to appreciate how “Earth is a finite place.” It’s increasingly clear that our species scientists have gained insights from the apparent movements of must learn how to live within our means—whether it comes to those twinkling orbs. But it’s striking how energy, food, water or any other resource. much of astronomy involves looking for One way we do that is to use less as a spe indirect clues to something unseen. As an cies. And fewer people use fewer resources. under graduate, I reflected on how Nep We have been improving on that score, tune revealed itself by subtly shifting the with a global average of 2.5 births per wo orbit of Uranus. Then Pluto was found man, about half the level of six decades when astronomers thought (incorrectly) ago. But challenges remain where popula that something was pulling on Uranus tions are still rising steeply. In “Six Billion and Neptune. in Africa,” starting on page 56, Engelman Now, as staff editor Michael D. Lem reports that fertility remains high in most onick writes, “Something very odd seems of Africa’s 54 countries—high enough that to be going on out beyond Pluto.” Could it by 2100 the continent’s 1.2 billion could be another hidden world? In our cover swell to between three billion and 6.1 bil story, “The Search for Planet X,” Lemon lion, adding further challenges to the econ ick describes how “super Earths”—plan omies and systems in some of the world’s COULD PLANET X EXIST? Although ets with up to roughly 10 times Earth’s poorest regions. Giving women opportuni Nicolaus Copernicus’s 1543 heliocentric mass—could be circling the sun beyond model of the universe was not correct, his ties and choices over their lives has per our current range of discovery. Today concentric rings evoke the widening quest. haps the greatest potential. As Engelman they are too far to be detected, but per says, “The empow er ment of women needs haps future observatories could confirm them, if they exist. no demographic justification,” but it is nonetheless a critical fac Meanwhile we can enjoy the tale of the hunt for the latest icy tor in helping Africa move toward a more prosperous future. BOARD OF ADVISERS Leslie C. Aiello Kaigham J. Gabriel Christof Koch Martin A. Nowak Terry Sejnowski President, Wenner-Gren Foundation President and Chief Executive Officer, President and CSO, Director, Program for Evolutionary Professor and Laboratory Head for Anthropological Research Charles Stark Draper Laboratory Allen Institute for Brain Science Dynamics, and Professor of Biology and of Computational Neurobiology of Mathematics, Harvard University Laboratory, Salk Institute for Roger Bingham Harold “Skip” Garner Lawrence M. Krauss Robert E. Palazzo Biological Studies Co-Founder and Director, Director, Medical Informatics and Director, Origins Initiative, Dean, University of Alabama at Michael Shermer The Science Network Systems Division, and Professor, Virginia Arizona State University Birmingham College of Arts and Sciences Publisher, Skeptic magazine Bioinformatics Institute, Virginia Tech Arthur Caplan Morten L. Kringelbach Carolyn Porco Michael Snyder Director, Division of Medical Ethics, Michael S. Gazzaniga Director, Hedonia: TrygFonden Leader, Cassini Imaging Science Professor of Genetics, Stanford Department of Population Health, Director, Sage Center for the Study Research Group, University of Oxford Team, and Director, CICLOPS, University School of Medicine NYU Langone Medical Center of Mind, University of California, and University of Aarhus Space Science Institute Michael E. Webber Vinton Cerf Santa Barbara Steven Kyle Vilayanur S. Ramachandran Co-director, Clean Energy Incubator, Director, Center for Brain and Cognition, and Associate Professor, Chief Internet Evangelist, Google David J. Gross Professor of Applied Economics and Department of Mechanical Engineering, University of California, San Diego George M. Church Professor of Physics and Permanent Management, Cornell University University of Texas at Austin Lisa Randall Director, Center for Computational Member, Kavli Institute for Theoretical Robert S. Langer Steven Weinberg Professor of Physics, Genetics, Harvard Medical School Physics,University of California, Santa David H. Koch Institute Professor, Director, Theory Research Group, Harvard University Rita Colwell Barbara (Nobel Prize in Physics, 2004) Department of Chemical Department of Physics, Martin Rees University of Texas at Austin Distinguished University Professor, Lene Vestergaard Hau Engineering, M.I.T.