|  |  | 
   
    |  |  |  |  |  |  |  |  |  |  |  |  |  
    | • | Just 400 years ago: 
 |  |  
    |  | (Oct. 9, 1604) 
 |  |  
    |  |  
    | • | Then a bright, naked eye 
 |  |  
    |  | object (no telescopes) 
 |  |  
    |  |  
    | • | It’s still blowing up – now 
 |  |  
    |  | 14 light years wide and 
 |  |  
    |  | expanding at 4 million mph. 
 |  
    |  |  
    | • | There’s material there at 
 |  |  
    |  | MANY temperatures, so 
 |  |  
    |  | many wavelengths are 
 |  |  
    |  | needed to understand it. 
 |  |  |  |