In spiral galaxies, the tightness of the winding of the spiral arms appears to be related directly to the
A) age of the galaxy, as determined from the age of its individual stars.
B) number of globular clusters in the halo of the galaxy.
C) overall intrinsic size of the galaxy, or the diameter across the spiral arms.
D) size of the central bulge of the galaxy.

Question

Quizplus · Accepted Answer

The tightness of the spiral arms in spiral galaxies is directly related to the size of the central bulge. Galaxies with larger central bulges tend to have more tightly wound spiral arms, while those with smaller bulges have more loosely wound arms. This relationship is a key observation in the study of galaxy morphology and structure.

In Spiral Galaxies, the Tightness of the Winding of the Spiral