The first gliding mammal winged through forests at least 70 million years earlier than scientists had previously presumed, a new fossil shows. The specimen dates from about 150 million years ago, during the time when birds were developing flight."This changes our view about the early evolution of mammals," says Jin Meng of the American Museum of Natural History in New York City. Scientists had proposed that mammals from that period "lived in the shadow of dinosaurs and were relatively primitive," Meng says. He and his colleagues report the finding in the Dec. 14 Nature.Farmers found the new fo... (p. 417)

A new method for cutting cake yields slices that make everyone equally happy. (p. 390)

Antique whale oil shows that some mysterious compounds that resemble DDT and PCBs are naturally produced. (p. 278)

The first high-resolution images sent by the Mars Reconnaissance Orbiter support the notion that water once flowed across much of the Red Planet. (p. 260)

NASA's Mars Reconnaissance Orbiter has just completed a week of picture taking from as low as 300 kilometers above the surface of the Red Planet.

In high dimensions, disorderly arrangements of spheres pack together more densely than orderly arrangements do. (p. 244)

The earliest-known bird had feathers on its legs that may have provided lift for flight, improving its maneuverability. (p. 197)