Adam Cole/NPR

Channel-billed toucans are important seed dispersers in rain forests. Courtesy of Lindolfo Souto/AAAS/Science hide caption

itoggle caption Courtesy of Lindolfo Souto/AAAS/Science

The metal in an Egyptian iron bead dating from around 3,300 BC has been found to have originated from space, according to analysis. Here, the bead is seen in (clockwise from top left) a photograph, a CT cross-section view, a model of nickel oxides, and a model in which blue areas represent the rich presence of nickel inside the bead. The Open University/University of Manchester hide caption

itoggle caption The Open University/University of Manchester

The small patch in the middle of the image is Aulacomnium turgidum, a type of bryophyte plant. Researchers in the Canadian Arctic say they are surprised the bryophytes were still green, even after being covered by ice. Courtesy of Caroline La Farge hide caption

itoggle caption Courtesy of Caroline La Farge

The origin of itch has confounded scientists for decades. Oktay Ortakcioglu/iStockphoto.com hide caption

itoggle caption Oktay Ortakcioglu/iStockphoto.com