HW 8 Solutions
•Question 11   (1 point) One fundamental requirement for an object to be a good tracer (i.e. marker) of the galaxy's spiral arms is that it be
 a.moving with small radial velocity (relative to earth).   b.moving with large radial velocity (relative to earth).   c. a short lived and therefore young object.   d. a very long lived and therefore probably old object.   
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