Scientists have found at least three and perhaps four planets that appear to be in the habitable zone of a triple-star system. Finding so many exoplanets in one star system's habitable zone is a first.
Grand Canyon tightrope walk: Funambulist Nik Wallenda traversed a 1,500-foot gorge near the Grand Canyon on a 2-inch-thick steel cable on Sunday, carrying with him a 43-lb. pole. Why did he bring such a heavy pole?
Laos' controversial Xayaburi Dam could bring the Giant Catfish to extinction, as well as devastate the Mekong River's other fisheries. The challenge: How to build a dam that allows a 600-pound fish to swim up stream?