Orangutans can get exercise and look down their noses at zoo visitors, thanks to cables that stretch from one side of the primate habitat to the other. Karen Bleier/AFP/Getty Images hide caption

itoggle caption Karen Bleier/AFP/Getty Images

A lone emperor penguin makes his rounds, at the edge of an iceberg drift in the Antarctic's Ross Sea in 2006. John Weller/AP hide caption

itoggle caption John Weller/AP

An iceberg floats through the water in Ilulissat, Greenland, in July. Researchers are studying how climate change and melting glaciers will affect the rest of the world. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

A rig drills a hydraulic fracturing well for natural gas outside Rifle, Colo., in March. Brennan Linsley/AP hide caption

itoggle caption Brennan Linsley/AP

The surface tower at a drill site, under construction during blistering Antarctic winds. Data from instruments, deployed through 450 meters of ice, is transmitted from the tower by satellite back to the Naval Postgraduate School. Image courtesy of Tim Stanton hide caption

itoggle caption Image courtesy of Tim Stanton

This artist's illustration shows the Voyager 1 space probe. The spacecraft was launched on Sept. 5, 1977, and as of August 2012, it is outside the bubble of hot gas, known as the "heliopause," that radiates from the sun. NASA/Landov hide caption

itoggle caption NASA/Landov