This tooth, which was also found in Denisova Cave, has a DNA structure similar to that of a finger bone. Its shape and physical structure are, however, very different from that of Neanderthals and modern humans, leading researchers to believe that the Denisovans are a distinct group. David Reich, et al./Nature hide caption

itoggle caption David Reich, et al./Nature

Semiconductor computer chips like this one rely on electricity -- positive or negative charges -- to store data. Using high power magnets in a lab, researchers have developed a new way to store data in the spin of an atom's nucleus. HYNIX/AFP/Getty Images hide caption

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Eat Up: Eating a large meal at the holidays won't have a big impact on your weight, says one physiologist. That's because your brain keeps a close watch on food intake and can tolerate the occasional big meal. It's slow, steady weight gain that's more problematic. hide caption

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City of Miami police officer E. Dominguez conducts a field sobriety test in 2007. One approach to reducing traffic deaths that's common in Europe is frequent roadside sobriety checks, says Adrian Lund, president of the Insurance Institute for Highway Safety. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images

A fruit fly larva's body is covered with a network of photosensing neurons that help it detect and avoid light. The cells glow under a light with the help of a green fluorescent protein. Dr. Chun Han/University of California, San Francisco hide caption

itoggle caption Dr. Chun Han/University of California, San Francisco

Scientists at Stanford argue that the same genes responsible for immunity in chimps may also be the reason humans have such big brains. Above, a young chimpanzee at Sydney's Taronga Zoo. Mark Kolbe/Getty Images hide caption

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Virgin Galactic is developing a suborbital spacecraft to carry spaceflight participants to about 65 miles above Earth. The craft, SpaceShipOne, is carried high above the Earth by a special plane called The White Knight, then launched. Courtesy of Scaled Composites hide caption

itoggle caption Courtesy of Scaled Composites

Bates and his research team used pingpong balls and red pipe cleaners to model the "hairy spherical block copolymer particles." The actual spheres are roughly 1 million times smaller, and each contains about 200 polymer molecules, represented by the red pipe cleaners. Courtesy of Frank Bates hide caption

itoggle caption Courtesy of Frank Bates

A dwarf minke whale swims near the Great Barrier Reef. Scientists say whale dung can help feed hungry fish near the surface of the ocean. Kike Calvo/AP hide caption

itoggle caption Kike Calvo/AP