President Obama, seen here inspecting solar panels on the roof of the Department of Energy, has submitted a U.S. pledge to reduce greenhouse gases. Kevin Lamarque/Reuters/Landov hide caption

itoggle caption Kevin Lamarque/Reuters/Landov

Not many students have the cutting-edge cybersecurity skills the NSA needs, recruiters say. And these days industry is paying top dollar for talent. Brooks Kraft/Corbis hide caption

itoggle caption Brooks Kraft/Corbis

About twice a year, statistics suggest, a pilot somewhere in the world — usually flying alone — deliberately crashes a plane. The Germanwing flight downed last week may be one such case. But most people who fit the psychological profile of the pilots in these very rare events never have problems while flying. Patrik Stollarz/AFP/Getty Images hide caption

itoggle caption Patrik Stollarz/AFP/Getty Images

Hawaii ranks 49th in the nation for use of home health care services during the last six months of someone's life. Videos from ACP Decisions show patients what their options are at the end of life. ACP Decisions hide caption

itoggle caption ACP Decisions

Needle exchange programs, like this one in Portland, Maine, offer free, sterile syringes and needles to drug users. The programs save money and lives, health officials say, by curtailing the spread of bloodborne infections, such as hepatitis and HIV. Robert F. Bukaty/AP hide caption

itoggle caption Robert F. Bukaty/AP

Smart phones contain a silicon chip inside the camera that might be used to detect rare, high energy particles from outer space. J. Yang/Courtesy of WIPAC hide caption

itoggle caption J. Yang/Courtesy of WIPAC

Game designer Jane McGonigal says we need to harness the beneficial aspects of video games. James Duncan Davidson/Courtesy of TED hide caption

itoggle caption James Duncan Davidson/Courtesy of TED

Primatologist Isabel Behncke Izquierdo says play helps to foster creativity, trust, and cooperation. James Duncan Davidson/Courtesy of TED hide caption

itoggle caption James Duncan Davidson/Courtesy of TED

NASA astronaut Scott Kelly is seen inside a Soyuz simulator at the Gagarin Cosmonaut Training Center on March 4 in Star City, Russia. Kelly, along with Russian cosmonaut Mikhail Kornienko of the Russian Federal Space Agency, are scheduled for launch Friday aboard a Soyuz TMA-16M spacecraft from the Baikonur Cosmodrome in Kazakhstan. NASA/Bill Ingalls hide caption

itoggle caption NASA/Bill Ingalls

Workers at Los Alamos National Laboratory used organic cat litter to clean up nuclear waste. The litter triggered chemical reactions that later caused a drum to burst. Department of Energy/Flickr hide caption

itoggle caption Department of Energy/Flickr

A 2008 view of the leading edge of the Larsen B ice shelf, extending into the northwest part of the Weddell Sea. Huge, floating ice shelves that line the Antarctic coast help hold back sheets of ice that cover land. Mariano Caravaca /Reuters/Landov hide caption

itoggle caption Mariano Caravaca /Reuters/Landov

A drone built by Agribotix, a Boulder startup, flies over a farm in Weld County, Colo. The drone has a camera that snaps a high-resolution photo every two seconds. From there, Agribotix stitches the images together, helping the farmer see what's happening in a field. Luke Runyon/Harvest Public Media/KUNC hide caption

itoggle caption Luke Runyon/Harvest Public Media/KUNC

The H1N1 swine flu virus kills some people, while others don't get very sick at all. A genetic variation offers one clue. Centre For Infections/Health Pro/Science Photo Library/Getty Images hide caption

itoggle caption Centre For Infections/Health Pro/Science Photo Library/Getty Images

The male Asian subterranean termite (brown abdomen) and the female Formosan subterranean termite (orange abdomen) are surrounded by their hybrid offspring (eggs, larvae, workers, soldiers) in an eight-month-old colony. Thomas Chouvenc/University of Florida hide caption

itoggle caption Thomas Chouvenc/University of Florida