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- [Source: NASA Goddard Space Flight Center News, http://www.nasa.gov/centers/goddard/news/topstory/2009/gems_explore.html ]
An exciting new astrophysics mission led by NASA’s Goddard Space Flight Center in Greenbelt, Md., will provide a revolutionary window into the universe. Named the Gravity and Extreme Magnetism Small Explorer (GEMS), the satellite will be the first to systematically measure the polarization of cosmic X-ray sources.
"To date, astronomers have measured X-ray polarization from only a single object outside the solar system -- the famous Crab Nebula, the luminous cloud that marks the site of an exploded star," said Jean Swank, a Goddard astrophysicist and the GEMS principal investigator. “We expect that GEMS will detect dozens of sources and really open up this new frontier."
Goddard will provide the X-ray mirrors and polarimeter instrument for GEMS and oversee the mission's science operations center, science data processing and systems engineering. Electromagnetic radiation -- light, radio waves, X-rays -- contains a varying electric field. Polarization refers to this field's direction. An everyday example of putting polarization to use is as close as a pair of sunglasses. Reflected light contains an electric field with a specific orientation. Because polarized sunglasses block light vibrating in this direction, they can reduce the glare of reflected sunlight. The extreme gravitational field near a spinning black hole not only bends the paths of X-rays, it also alters the directions of their electric fields. Polarization measurements can reveal the presence of a black hole and provide astronomers with information on its spin. Fast-moving electrons emit polarized X-rays as they spiral through intense magnetic fields, providing GEMS with the means to explore another aspect of extreme environments.
"Thanks to these effects, GEMS can probe spatial scales far smaller than any telescope can possibly image," Swank said. Polarized X-rays carry information about the structure of cosmic sources that isn't available in any other way. Group: Platform_Details Entry_ID: GEMS Group: Platform_Identification Platform_Category: Solar/Space Observation Satellites Platform_Series_or_Entity: NASA Small Explorer (SMEX) Short_Name: GEMS Long_Name: Gravity and Extreme Magnetism Small Explorer End_Group Creation_Date: 2009-08-11 Online_Resource: http://www.nasa.gov/centers/goddard/news/topstory/2009/gems_explore.html Online_Resource: http://heasarc.gsfc.nasa.gov/docs/gems/ Online_Resource: http://explorers.gsfc.nasa.gov/ Sample_Image: http://www.nasa.gov/centers/goddard/images/content/376204main_GEMS_labeled_226.jpg Group: Platform_Logistics Launch_Date: 2014-07-01 Design_Life: 2 years Primary_Sponsor: USA/NASA End_Group End_Group
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