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

A replica of the pinky bone fragment found in a Siberian cave. Researchers used the bone bit to extract and sequence the genome of a girl who lived tens of thousands of years ago. Max Planck Institute for Evolutionary Anthropology hide caption

itoggle caption Max Planck Institute for Evolutionary Anthropology

Roger Angel, an astronomer at the University of Arizona, stands in front of his new project: a solar tracker. Angel wants to use the device to harness Arizona's abundant sunlight and turn it into usable energy. Jason Millstein for NPR hide caption

itoggle caption Jason Millstein for NPR

Adam Steltzner, the leader of the rover's entry, descent and landing engineering team, cheers after Curiosity touched down safely on Mars on Sunday. Bill Ingalls/NASA/Getty Images hide caption

itoggle caption Bill Ingalls/NASA/Getty Images

An artist's concept of NASA's Mars Science Laboratory spacecraft depicts the final minute before the rover, Curiosity, touches down on the surface of Mars. NASA/JPL-Caltech hide caption

itoggle caption NASA/JPL-Caltech

NASA engineer Adam Steltzner led the team that designed a crazy new approach to landing on Mars. Rachael Porter for NPR hide caption

itoggle caption Rachael Porter for NPR

United States runner Kam Conley sheds layers to train for the Olympics in England on Monday. Less clothing means more evaporation, keeping athletes cooler. Hussein Malla/AP hide caption

itoggle caption Hussein Malla/AP