Artificial light makes the modern world possible. But not all kinds of light are good for us. Electric light has fundamentally altered our lives, our bodies and the very nature of our sleep.
One of NASA's most senior and still-operational spacecraft reached a milestone: the rover Opportunity completed its first 25 miles traveling across the surface of Mars!
Recently, NASA administrator Charles Bolden rephrased the "Moon, Mars and Beyond" mission plan to better align the steps toward Mars with budgetary realities and to balance human space programs with more cost-effective robotic missions.