Researchers say they have identified traces of ice in craters on Mercury, seen here in this Oct. 8, 2008, image from the Messenger spacecraft. NASA hide caption

itoggle caption NASA

NASA's Mars rover Curiosity dug up five scoops of sand from a patch nicknamed "Rocknest." A suite of instruments called SAM analyzed Martian soil samples, but the findings have not yet been released. NASA/JPL-Caltech hide caption

itoggle caption NASA/JPL-Caltech

A man crosses a flooded street in the wake of Superstorm Sandy on Thursday in Little Ferry, N.J. Surprise coastal surge floods caused by the storm battered Little Ferry, Moonachie and some other towns along the Hackensack River in Bergen County, all areas unaccustomed to flooding. Mike Groll/AP hide caption

itoggle caption Mike Groll/AP

An emergency responder helps residents of Little Ferry, N.J., after their neighborhood was flooded due to Superstorm Sandy. Andrew Burton/Getty Images hide caption

itoggle caption Andrew Burton/Getty Images

Urushiol, the chemical in poison ivy, is also harvested from the Japanese lacquer tree to coat lacquerware. Here, a rash caused by lacquerware that likely was not properly cured. Kenji Kabashima hide caption

itoggle caption Kenji Kabashima

A mural in an ancient tomb in China shows a troupe of eunuchs. How long did they live? Wikimedia Commons hide caption

itoggle caption Wikimedia Commons

The genetic factors responsible for a cat's stripes might help researchers understand disease resistance in humans. kennymatic via Flickr hide caption

itoggle caption kennymatic via Flickr

A health worker in the Domincan Republic sprays insecticide between houses to stop dengue fever outbreaks this month. Erika Santelices/AFP/Getty Images hide caption

itoggle caption Erika Santelices/AFP/Getty Images

A male Solenosteira macrospira, left, carries snail eggs on its shell. But not all of the eggs were fertilized by him. Females, like the one on the right, deposit the eggs into papery capsules and attach them to the males' shells. P.B. Marko/Ecology Letters hide caption

itoggle caption P.B. Marko/Ecology Letters

Catherine Wong used electrical components to build an electrocardiogram that sends data by cellphone. Courtesy of Catherine Wong hide caption

itoggle caption Courtesy of Catherine Wong