Density waves may explain
A) the lack of blue stars in the halo.
B) the random orbits of halo stars.
C) the density of red stars in the bulge.
D) the spiral arm structure of the Galaxy.
E) the large number of open clusters in the halo.
While observing the Sun, you note a large number of sunspots. What can you conclude?
A) The Sun is less luminous than usual.
B) This is a period of low solar activity.
C) Earth’s climate will be unusually cold.
D) The Sun’s rotation is slower than average.
E) There are likely to be an above average number of flares and prominences.