"A Need For New Warheads?", by David Biello: Countries are altering their nuclear arsenals, prompting the U.S. to refurbish its own warheads. Hear how America's proposal to build the first new nuclear warhead in two decades is rasing a host of questions.
"The Great Roller Coaster Ride", by Cliff Burgess and Fernando Quevedo: Can cosmic inflation be a sign that our universe is in a far vaster realm?
"Cell Defenses and The Sunshine Victim", by Luz Tavera-Mendoza and John White:Vitamin D does much more than build strong bones - and many people aren't getting enough of it.
"Brilliant Displays", by M. Mitchell Waldrop: A new technology is making cell phone displays bright and clear - even in the sun.
"The Science of Doing Good", by Sheri Fink: Satellite imaging and research carried out in disaster-relief areas have begun to make humanitarian aid more efficient.