Astronomy and astrology were often practiced together in ancient cultures, and astrology played an important role in the historical development of astronomy.
Indicate whether the statement is true or false
Question 2
The leading explanation for the existence of spiral arms is
A) shock waves from cyclic supernovae explosions.
B) shock wave from the quasar-like eruption of the Galactic core.
C) passages of spiral density waves through the interstellar medium.
D) passages of massive globular clusters through the Galactic plane.
E) tidal streams of small galaxies being torn up by our monster Galaxy.