Treasury Secretary Henry Paulson speaks on Sept. 7, 2008, during a news conference on the bailout of mortgage giants Fannie Mae and Freddie Mac. Susan Walsh/AP hide caption

The moon is generally thought to be a dry place, and the discovery of water on its surface comes as an unexpected — and exciting — surprise for researchers. Carolina K. Smith/iStockphoto.com hide caption

U.S. Marines with Golf Company, 2nd Battalion, 3rd Regiment run to take position behind a building after being fired on by Taliban while on patrol in the village of Dahaneh, in Helmand province, Afghanistan, on Aug. 28. Julie Jacobson/AP hide caption