NASA says it has found proof that water shaped the rocks on the left, in a photograph taken by the Mars rover Curiosity (left). For comparison, the agency released an image of rocks from Earth (right). NASA hide caption

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NASA says it has found proof that water shaped the rocks on the left, in a photograph taken by the Mars rover Curiosity (left). For comparison, the agency released an image of rocks from the Earth (right). NASA hide caption

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Spectators Mario Vasquez, 40, of Redondo Beach and his son Mario Jr., 2, watch as space shuttle Endeavour, atop NASA's Shuttle Carrier Aircraft, prepares to land at Los Angeles International Airport Friday. Ringo H.W. Chiu/AP hide caption

itoggle caption Ringo H.W. Chiu/AP

Space shuttle Endeavour, attached to a 747, on the tarmac at the Kennedy Space Center in Florida. Bill Ingalls/NASA /UPI /Landov hide caption

itoggle caption Bill Ingalls/NASA /UPI /Landov

Space shuttle Endeavour is towed to the Kennedy Space Center landing facility in Cape Canaveral, Fla., on Friday. John Raoux/AP Photo hide caption

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The Soyuz capsule lands with Commander Gennady Padalka of Russia, NASA Flight Engineer Joe Acaba and Russian Flight Engineer Sergei Revin aboard, near the town of Arkalyk, Kazakhstan. The capsule's final meter of descent is eased by braking engines. Carla Cioffi/NASA hide caption

itoggle caption Carla Cioffi/NASA

On its way to Jupiter, the Galileo spacecraft looked back and captured this remarkable view of Earth and the moon. The image was taken from a distance of about 3.9 million miles. NASA hide caption

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