Radar images of asteroid 1998 QE2, taken when the cosmic traveler was about 3.75 million miles from Earth, revealed that the asteroid, with a 1.7-mile diameter, has a moon or satellite revolving around it. NASA/JPL-Caltech/GSSR hide caption

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Headed To Mars? Watch Out For Cosmic Rays

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The Antares rocket lifts off from the launchpad at the NASA facility on Wallops Island Va., Sunday, beginning a test mission that has now been deemed a success. The Orbital Sciences Corp. rocket will eventually deliver supplies to the International Space Station. Steve Helber/AP hide caption

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Apollo 11 climbs toward orbit after liftoff on July 16, 1969. In 2 1/2 minutes of powered flight, the S-IC booster lifts the vehicle to an altitude of about 39 miles, some 55 miles downrange. NASA hide caption

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Carnegie Lake, Australia, 1999 Carnegie Lake in Western Australia fills with water only during periods of significant rainfall. In dry years, it is reduced to a muddy marsh. Flooded areas appear dark blue or black, vegetation appears in shades of dark and light green, and sands, soils and minerals appear in a variety of colors. NASA hide caption

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A replica Mayan Calendar Round showing the date September 21, 2004, opening day for the Smithsonian's National Museum of the American Indian. Molly Stephey/Smithsonian's National Museum of the American Indian hide caption

toggle caption Molly Stephey/Smithsonian's National Museum of the American Indian