FROM THE EDITOR Mariette DiChristina is editor in chief of Scientific American. Follow her on Twitter @mdichristina sounds so harsh have been beneficial, you ask? To find out, In the Beginning please turn to page 28. The sun’s rays provided vitality for this world. Seeing them There was light. But then what happened? dim temporarily, as they do during a solar eclipse, is awe­inspir­ How did life arise on the third rocky planet orbiting the un­ ing. It’s been nearly a century since a total solar eclipse has remarkable star at the center of our solar system? Humans crossed the U.S. from coast to coast. Starting on page 54, you’ll have been wondering about the answer to that question prob­ find that “The Great Solar Eclipse of 2017,” by Jay M. Pasachoff, ably almost as long as we’ve been able to wonder. In recent tells you everything you need to know about this rare event. And decades scientists have made some a companion piece, “1,000 Years of gains in understanding the conceiv­ Solar Eclipses,” by senior editor Mark able mechanisms, gradually settling Fischetti, with illustrations by senior on a possible picture of our origins graphics editor Jen Christiansen and in the oceans. The idea was that designer Jan Willem Tulp, tells you hydrothermal vents at the bottom of what you will need to know as well. I the seas, protected from cataclysms like to think that the readers of Scien - rending the surface four billion tific American,which turns 172 this years ago, delivered the necessary month, will be enjoying the solar energy and could have sustained the shows well into the future. molecules needed. If they do enjoy them, it’ll be be ­ Perhaps not. Water was a neces­ cause we’ve fostered a love of learn­ sary ingredient,­­ surely, but that LIFE on Earth could have arisen in places similar to the ing about the world around us. How doesn’t mean we sprang from oceans, Grand Prismatic Spring in Yellowstone National Park. we teach and create the right learn­ according to researchers Martin J. ing environments are critical to our Van Kranendonk, David W. Deamer and Tara Djokic in our students’ success. For that reason, we’ve taken an evidence­ cover story, “Life Springs.” Oceans, they write, might have based look at the concept of vouchers in education in “A Matter spread the needed molecules too quickly for cell membranes of Choice,” by journalist Peg Tyre, starting on page 48. The con­ and functions to occur. Instead they argue, land pools in an ac­ cept is a keystone of the current administration’s plan to re­ tive volcanic landscape that repeatedly dried and got wet again vamp education, but research finds it wanting. Fortunately, could have cradled the seeds of life. How could something that there is still time to make a choice. 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 Roger Bingham Harold “Skip” Garner Lawrence M. Krauss of Mathematics, Harvard University Laboratory, Salk Institute for Co-Founder and Director, Director, Origins Initiative, Biological Studies The Science Network Executive Director and Professor, Robert E. Palazzo Arizona State University Michael Shermer Arthur Caplan Primary Care Research Network Dean, University of Alabama at Publisher, Skeptic magazine Director, Division of Medical Ethics, and Center for Bioinformatics and Morten L. Kringelbach Birmingham College of Arts and Sciences Associate Professor and Senior Michael Snyder Department of Population Health, Genetics, Edward Via College Carolyn Porco NYU Langone Medical Center of Osteopathic Medicine Research Fellow, The Queen’s College, Professor of Genetics, Stanford Leader, Cassini Imaging Science Vinton Cerf University of Oxford University School of Medicine Michael S. Gazzaniga Team, and Director, CICLOPS, Chief Internet Evangelist, Google Steven Kyle Michael E. Webber Director, Sage Center for the Study Space Science Institute George M. Church of Mind, University of California, Professor of Applied Economics and Co-director, Clean Energy Incubator, Director, Center for Computational Management, Cornell University Vilayanur S. Ramachandran Santa Barbara and Associate Professor, Genetics, Harvard Medical School Robert S. Langer Director, Center for Brain and Cognition, Department of Mechanical Engineering, David J. Gross Rita Colwell David H. Koch Institute Professor, University of California, San Diego University of Texas at Austin Distinguished University Professor, Professor of Physics and Permanent Department of Chemical Lisa Randall Steven Weinberg University of Maryland College Park Member, Kavli Institute for Theoretical Engineering, M.I.T. Professor of Physics, Director, Theory Research Group, and Johns Hopkins Bloomberg School Physics,University of California, Santa Lawrence Lessig Department of Physics, of Public Health Barbara (Nobel Prize in Physics, 2004) Harvard University Richard Dawkins Professor, Harvard Law School Martin Rees University of Texas at Austin Lene Vestergaard Hau (Nobel Prize in Physics, 1979) Founder and Board Chairman, John P. Moore Astronomer Royal and Professor Richard Dawkins Foundation Mallinckrodt Professor of Physics and George M. Whitesides Professor of Microbiology and of Cosmology and Astrophysics, Drew Endy of Applied Physics, Harvard University Immunology, Weill Medical Professor of Chemistry and Institute of Astronomy, University Professor of Bioengineering, Danny Hillis College of Cornell University Chemical Biology, Harvard University Stanford University of Cambridge Co-chairman, Applied Minds, LLC M. Granger Morgan Anton Zeilinger Edward W. Felten Daniel M. Kammen Hamerschlag University Professor Jeffrey D. Sachs Professor of Quantum Optics, Director, Center for Information Class of 1935 Distinguished Professor Director, The Earth Institute, Quantum Nanophysics, Quantum Technology Policy, Princeton University Engineering and Public Policy, Carnegie Mellon University Columbia University Information, University of Vienna Jonathan Foley of Energy, Energy and Resources Executive Director and Group, and Director, Renewable and Miguel Nicolelis Eugenie C. Scott Jonathan Zittrain William R. and Gretchen B. Kimball Chair, Appropriate Energy Laboratory, Co-director, Center for Chair, Advisory Council, Professor of Law and of Computer California Academy of Sciences University of California, Berkeley Neuroengineering, Duke University National Center for Science Education Science, Harvard University GETTY IMAGES 4 Scientific American, August 2017 Illustration by Nick Higgins sad0817Edit2p.indd 4 6/20/17 6:10 PM.