Radio Maps of the Spiral Arms of Our Galaxy

Multiple Choice

Radio maps of the spiral arms of our galaxy

A) reveal that our galaxy is a grand design spiral.
B) map the location of hot O and B stars by the radio radiation they emit.
C) reveal that the spiral arms are winding up and growing closer together.
D) reveal that the Sun is currently located in the center of a spiral arm.
E) map the location of dense neutral hydrogen clouds.