In the condensation theory of the Moon's origin
a. the Moon broke from a rapidly spinning Earth
b. the Earth and its Moon formed from the same cloud of matter
c. the Moon formed elsewhere in the solar nebula and was later captured by Earth.
d. the Moon formed when a very massive planetesimal smashed into the young Earth.
Question 2
___________ can be used to determine the galaxy's mass if the galaxy is reasonably close so that the Doppler shift of the galaxy disk material can be measured at several distances from the galaxy's center relative to the center.
a. The Hubble constant
b. A galaxy's color
c. A galaxy's rotation curve
d. A galaxy's diameter
e. The velocity dispersion method
