11.A ____ generally contains well over 1000 galaxies and quite : 1777263
11.A ____ generally contains well over 1000 galaxies and is quite dense. They often contain many giant elliptical galaxies.
12.The Milky Way is part of
a poor cluster.
a rich cluster.
the Virgo Cluster.
the Local Group.
A.I and III
B.I and IV
C.II and III
D.II and IV
13.__________ are produced when two galaxies pass near each other and pull large streamers of stars, gas, and dust away from the galaxies.
14.Mathematical models indicate that ____ galaxies are produced by high speed collisions in which a smaller galaxy passes through another galaxy almost perpendicular to the disk of the galaxy.
15.Which of the following is not used as a distance indicator for galaxies?
A.Large globular clusters
C.H II regions
D.Cepheid variable stars
16.The look-back time is
A.the time it takes for the light from an object to reach Earth.
B.numerically equal to the distance in light-years.
C.smaller for more distant objects.
D.all of the above
E.a and b above
17.The mass of a single galaxy might be found by
A.the double galaxy method.
B.the rotation curve method.
C.the cluster method.
D.any of these methods.
E.none of these methods.
18.Most of the mass of a galaxy is contained in the
A.massive O and B stars in the galaxy.
B.H I regions of the galaxy.
C.H II regions of the galaxy.
D.dark matter of the galaxy.
E.disk of the galaxy.
19.Galactic cannibalism refers to
B.the merging of galaxies.
C.galaxies drawing in gas from the intergalactic medium.
D.the destruction of a galaxies globular clusters by the galaxies nucleus.
E.none of these
20.Astronomers now speculate that a galaxy's shape depends on all of the following except
A.the rate of star formation.
B.the history of past collisions.
D.All of these may be important in determining a galaxy’s shape