Spiral structure:
A) rotates at the same speed as the gas in the disk
B) rotates at a speed that is different than the gas in the disk
C) stays constant in time as the gas in disk rotates through it
D) rotates backward compared to the stellar orbits
E) must only last a short time, since few galaxies with disks show spiral patterns

Question

Quizplus · Accepted Answer

The spiral structure in galaxies is a density wave that rotates at a different speed than the gas and stars in the disk.

Spiral Structure