At Launch Pad 39A at NASA's Kennedy Space Center in Florida, a technician performs a final check of space shuttle Atlantis' payload bay doors before they are closed for launch. Cory Huston/NASA hide caption

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Space shuttle Atlantis awaits blastoff on its launch pad as members of the media set up remote cameras for Friday's scheduled launch from Kennedy Space Center in Florida to the International Space Station. Matt Stroshane/Getty Images hide caption

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In the study, people who washed their hands after making a tough choice seemed less worried about it. hide caption

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This illustration shows the asteroid 24 Themis flanked by two small fragments that broke off following a crash more than 1 billion years ago. The bottom fragment's cometlike tail comes from the sublimation of ice from its surface. Gabriel Perez, Servicio MultiMedia, Instituto de Astrofisica de Canarias, Tenerife, Spain hide caption

toggle caption Gabriel Perez, Servicio MultiMedia, Instituto de Astrofisica de Canarias, Tenerife, Spain

This newly released image from Hubble shows scorching radiation and fast winds from super-hot newborn stars are shaping this pillar of gas and dust. This stellar nursery is called the Carina Nebula and located 7,500 light-years away. NASA hide caption

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In the study, miniature GPS loggers weighing just 16 grams were fitted into custom-made backpacks carried by flocks of up to 10 homing pigeons. Courtesy of Zsuzsa Akos hide caption

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The crew of the space shuttle Discovery is set to launch Monday morning. Where will they go after the mission ends? John Raoux/AP hide caption

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A magnified view of a colony of embryonic stem cells from the H9 stem cell line, one of the few lines approved for federally funded research under the Bush administration. These cells are now off-limits under a new policy set up by President Obama. Public Domain, via Wikimedia hide caption

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The byssal threads help these mussels hang on to rocky outcroppings and might suggest a new way of making flexible but strong materials for industrial uses. jeffk/via flickr hide caption

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The development of NASA’s Ares I-X rocket would be halted if President Obama's budget for the space agency is approved. NASA/Kim Shiflett hide caption

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An artist's rendering of the 70-million-year-old fish Bonnerichthys. This large bony fish got its dinner much like today's whales, by slurping in water and filtering out tiny sea creatures. Image courtesy of Robert Nicholls, hide caption

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