The outer planets are composed of ____.
a. rock and ice
b. ice and gas
c. metal and ice
d. high density metals
e. low density gas
Question 2The most common type of star is a(n) ____.
a. white dwarf
b. lower-main-sequence star
c. upper-main-sequence star
d. giant
e. supergiant
Question 3The inner planets are composed of ____.
a. rock and ice
b. ice and gas
c. rock and gas
d. metal and ice
e. rock and metal
Question 4Which type of binary system have pairs of stars that are so close together that they look like one single point?
a. radio binary
b. eclipsing binary
c. visual binary
d. spectroscopic binary
e. neutron star binary
Question 5Laplace's nebular hypothesis was problematic in that he could not explain ____.
a. the different types of planets
b. the rotational direction of the planets
c. how the Sun had <0.5 of the Solar System's angular momentum
d. how one star could come within a close encounter of another star
e. how gravity was the dominant force of planet formation
Question 6On the H-R diagram, 90 percent of all stars are ____.
a. either giant or supergiant stars
b. white dwarfs
c. main sequence stars
d. sred dwarfs
e. binary stars