Author Question: Is space expanding within clusters of galaxies? A) No, because the universe is not old enough yet ... (Read 25 times)

Wadzanai · **on:** Jul 27, 2018

Is space expanding within clusters of galaxies?

A) No, because the universe is not old enough yet for these objects to have begun their expansion.
B) No, because expansion of the universe affects only empty space, not space in which matter is present.
C) Yes, and that is why clusters tend to grow in size with time.
D) No, because their gravity is strong enough to hold them together even while the universe as a whole expands.

Question 2

Spiral arms appear bright because

A) they contain more hot young stars than other parts of the disk.
B) they contain far more stars than other parts of the galactic disk.
C) they contain more molecular clouds than other parts of the disk.
D) they are the only places where we find stars within the disk of the galaxy.