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• Question 9 (1 point) If all the mass in our galaxy
were centrally concentrated,
we'd expect velocities to fall with increasing distance according to Kepler's laws. This is not seen in the
disks of spiral galaxies.
Galactic rotation curves appear "flat" with increasing distance. This must be due to
a. The gravitational influence of massive
globular clusters in the halo.
b. The difficulty in measuring velocities of stars in the galactic disk
because of all the gas and dust.
c. The fact that Kepler's laws do not apply over the 25 kpc size of the Milky Way galaxy
because the effect of gravity
travels only at the speed of light. d. The Spiral density wave traveling at a different speed than the stars in the
disk. e. The gravitaional influence of "dark
matter" in the halo.
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•Question 10 (1 point) The location of the sun
relative to the center of
our galaxy was FIRST CORRECTLY determined by
a. the relative brightness of the visible
Milky Way in different directions.
b. the positions of the globular clusters and
the properties
of the variable stars in them.
c. the position of supernova.
d. radio maps of the galaxy.
•Question 11 (1 pt) If you find a metal-rich star it
is more likely to be a
member of which Population? A. Population I (the disk)
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