The main ring of the Tevatron, seen in a time exposure. For a quarter century, the particle accelerator at a lab outside Chicago was the most powerful machine of its kind in the world. Reidar Hahn/Fermilab hide caption

itoggle caption Reidar Hahn/Fermilab

This picture of the Eros asteroid is the first of an asteroid taken from an orbiting spacecraft. The crater at the center is about 4 miles across. JPL/JHUAPL/NASA hide caption

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This artist's conceptual image shows the Upper Atmosphere Research Satellite, or UARS. After two decades in orbit, the satellite will make an uncontrolled re-entry into the Earth's atmosphere. NASA hide caption

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A view inside the Tevatron ring, currently in its final days as a particle superhighway. Reider Hahn/Fermilab hide caption

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Two polar bears spar on the shoreline of the Hudson Bay in November 2007. Paul J. Richards/AFP/Getty Images hide caption

itoggle caption Paul J. Richards/AFP/Getty Images

"Shrimp on a treadmill" has become a euphemism for questionable government spending on scientific research. The actual research study was focused on how water quality affects a shrimp's performance. Lou Burnett/College of Charleston hide caption

itoggle caption Lou Burnett/College of Charleston

A look inside the Dark Energy Camera shows the 74 blue-tinged sensors that detect light. The camera will survey distant, faint galaxies to learn more about dark energy. Reidar Hahn/Fermilab hide caption

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A polar bear researcher was suspended from his government job last month over allegations of federal contract mismanagement. Above, a polar bear on fresh ice in the Hudson Bay in November 2007. Paul J. Richards/AFP/Getty Images hide caption

itoggle caption Paul J. Richards/AFP/Getty Images

A wildlife biologist was flying over the Arctic on a routine whale survey when his team spotted dead polar bears in the water. The researcher's report on the observations raised public alarm about the threat of climate change, he's now under an official investigation. Above, a polar bear walks on the frozen tundra on the edge of Hudson Bay on Nov. 14, 2007. Paul J. Richards/AFP/Getty Images hide caption

itoggle caption Paul J. Richards/AFP/Getty Images

This artist's illustration shows a collision between the moon and a companion moon. Scientists say the collision could be responsible for the moon's asymmetric shape. Martin Jutzi and Erik Asphaug/Nature hide caption

itoggle caption Martin Jutzi and Erik Asphaug/Nature

Atlantis lifts off from Kennedy Space Center on its final flight on July 8. There are plans for a next-generation space vehicle, but some space experts aren't sure if the vehicle will ever be completed. Tony Gray and Tom Farrar/NASA hide caption

itoggle caption Tony Gray and Tom Farrar/NASA

A large section of Discovery's nose, called the forward reaction control system, which helped steer the shuttle while in orbit, was removed in March. The spacecraft will be cleaned and detoxified before being put on display in museums. Jim Grossmann/NASA hide caption

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A worker tests components on a model of the space shuttle before wind tunnel testing. NASA hide caption

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