Spiral arms appear bright because .
A)they contain more hot young stars than other parts of the disk
B)they are the only places where we find stars within the disk of the galaxy
C)they contain more molecular clouds than other parts of the disk
D)they contain far more stars than other parts of the galactic disk

Question

Quizplus · Accepted Answer

Spiral arms appear bright because they contain more hot young stars, which are dense and luminous, as compared to other parts of the disk. The high concentration of young stars makes these regions appear brighter and more prominent.

Spiral Arms Appear Bright Because