The space shuttle Challenger explodes shortly after lifting off from the Kennedy Space Center in Cape Canaveral, Fla., on Jan. 28, 1986. Bruce Weaver/AP hide caption

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To eat, chitons use their teeth, which look like black bulbs with bluish highlights, to grind up rock. Lyle Gordon/Northwestern University hide caption

itoggle caption Lyle Gordon/Northwestern University

The planet Kepler-10b, seen in this artist's drawing, is about 1.4 times the size of Earth and is the smallest planet ever discovered outside of our solar system. NASA hide caption

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A human baby typically weighs about 6 percent of what its mother weighs. This baby, seen on a beach in Costa Rica, crawls next to an olive ridley sea turtle. Yuri Cortez/AFP/Getty Images hide caption

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The Nintendo 3DS offers 3-D imagery without 3-D glasses. But scientists warn that if young children use the device in 3-D mode, it could be harmful to their vision. Shuji Kajiyama/AP hide caption

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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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