This system includes a sun-like star with six planets tightly orbiting it. At times, two or more planets pass in front of the star at once, as shown in this artist's conception of a simultaneous transit of three planets. This event was observed by the Kepler spacecraft on Aug. 26, 2010. Kepler-11 is located 2,000 light years from Earth.
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.