Density waves may explain
A) the lack of blue stars in the halo.
B) the random orbits of halo stars.
C) the large number of open clusters in the halo.
D) the density of red stars in the bulge.
E) the spiral arm structure of the Galaxy.

Question

Quizplus · Accepted Answer

Density waves are a theory that explains the spiral arm structure of galaxies. These waves move through the disk of the galaxy, compressing gas and dust and triggering star formation, which gives the spiral arms their bright, prominent appearance.

Density Waves May Explain