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Credit & Copyright: Roberto Colombari &  
Robert Gendler  
 
Explanation:
One of the brightest galaxies in planet Earth's sky is similar in size  
to our Milky  
Way Galaxy: big, beautiful M81.  
  
This grand spiral galaxy can be found toward the northern constellation of the Great  
Bear   
(Ursa Major).  
  
  
This superbly  
detailed view reveals M81's bright yellow nucleus, blue  
spiral arms, and sweeping cosmic dust lanes with a scale comparable to  
the  
Milky Way.  
  
Hinting at a disorderly past,  
a remarkable dust lane actually runs straight through the  
disk, to the left of the galactic center,  
contrary to M81's  
other prominent  
spiral features.  
  
The errant  
dust lane may be the lingering result of  
a close encounter between  
M81 and its smaller companion galaxy, M82.  
  
Scrutiny of variable stars in   
M81 has yielded one of the best  
determined  
distances for an external galaxy  -- 11.8 million light-years.  
  
  
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: spiral galaxy - dust lanes
Publications with words: spiral galaxy - dust lanes
See also:

