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          This image was selected as  picture of the day on the  English Wikipedia for  December 24, 2005. | 
         
        
        
        
        
       
        
         
          
           
            
             
              
               
                
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                   This is a featured picture on the English language Wikipedia ( Featured pictures) and is  considered one of the finest images. 
                   
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           | Description | 
           Tycho's Supernova Remnant. In 1572, the Danish astronomer  Tycho Brahe observed and studied the explosion of a star that became known as  Tycho's supernova. More than four centuries later,  Chandra's image of the supernova remnant shows an expanding bubble of multimillion degree debris (green and red) inside a more rapidly moving shell of extremely high energy electrons (filamentary blue). As a huge ball of exploding  plasma, it was  Irving Langmuir who coined the name plasma because of its similarity to  blood plasma, and  Hannes Alfvén who noted its cellular nature. The filamentary blue outer shell of X-ray emitting high-speed electrons is also a characteristic of plasmas. This is a  false-colour x-ray image in which the energy levels (in keV) of the x-rays have been assigned a colours as follows: Red 0.95-1.26 keV, Green 1.63-2.26 keV, Blue 4.1-6.1 keV. All x-rays images must use processed colours since x-rays (as are radio waves, infra-red) are invisible to the human eye. But they are not invisible to suitable equipment, such as x-ray telescopes. The red and green bands highlight the expanding cloud of  plasma with temperatures in the millions of degrees. | 
          
          
           | Date | 
           September 2005 | 
          
          
           | Source | 
            http://www.msfc.nasa.gov/news/news/photos/2002/photos02-218.html | 
          
          
           | Author | 
           NASA/CXC/Rutgers/J.Warren & J.Hughes et al. | 
          
         
         
         Licensing 
        
         
          
           | Public domainPublic domainfalsefalse | 
          
         
         
          
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           This file is in the  public domain because it was solely created by  NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See  Template:PD-USGov,  NASA copyright policy page or  JPL Image Use Policy.) | 
           
            
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             - The  SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use.  
 
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        Old file history 
        Originally uploaded on the En-Wiki by  en:User:Iantresman 12:40, 23 September 2005
        
        
        
       File usage
       
        The following pages on Schools Wikipedia link to this image (list may be incomplete):
        
        
       
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