At the first-ever Ironman triathlon in 1978, the 15 competitors read these instructions in the race guidelines: "Swim 2.4 miles! Bike 112 miles! Run 26.2 miles! Brag for the rest of your life!" Well, sure -- unless you die trying. A study presented Saturday at a meeting of the American College of Cardiology shows that the grueling triad of events is indeed particularly strenuous, with a risk of sudden death twice that of marathons.
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.