For those of you who sometimes wonder why string theory can be one of the most talked about scientific ideas of our day without a whisper of evidence backing it up—admit, there are a few of you out there—there's a very interesting and not too complex article in the new issue of Physics World. The piece reviews some of the history and progress of past scientific theories, and why considering only the big ideas that can be backed by some experimental proof isn't a good thing for advancing our understanding of the universe. The simplified conclusion: At this point, string theory is the only real candidate capable of pulling together gravity and quantum physics, so we might as well stick with it.—Gregory Mone
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.