Physics Naked SingularitiesBy Pankaj S. JoshiThe black hole has a troublesome sibling, the naked singularity. It is a point where space and time break down. Physicists have long thought—hoped—it could never exist. But they might be wrong.Medicine44 Nanomedicine Targets Cancer By James R. Heath, Mark E. Davis and Leroy HoodBy viewing the body as a system of molecular networks, future physicians will be able to target disruptions in that system with nanoscale technologies and thereby transform the diagnosis and treatment of malignancies and other diseases.Earth Science52 The Origin of the Land under the Sea By Peter B. KelemenThe deep basins under the oceans are carpeted with lava that spewed from submarine volcanoes—in a most unusual way.Space Technology58 New Dawn for Electric Rockets By Edgar Y. ChoueiriEfficient electric plasma engines are already propelling the next generation of space probes to the outer solar system. That is just the beginning.