If the spiral density wave were the only thing producing spiral arms,it would be expected that
A) all spiral arms would be dust free.
B) all galaxies would have grand design spiral patterns.
C) the Milky Way would be more massive than observed.
D) the Milky Way wouldn't have any spiral arms.
E) the halo component of the Milky way would show spiral arms as well.

Question

Quizplus · Accepted Answer

The spiral density wave theory suggests that spiral arms are formed due to density waves in the disk of a galaxy, leading to grand design spiral patterns. If this were the only mechanism, all galaxies would exhibit such patterns.

If the Spiral Density Wave Were the Only Thing Producing