The lower edge of the Main Sequence band is known as ____ and represents the location in the HR-diagram at which stars begin their lives as main sequence stars
a. the Coulomb barrier
b. hydrostatic equilibrium
c. the birth line
d. the zero-age main sequence
e. the evolutionary track
D
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The term light year describes a measurement of _____.
A. Distance B. Prior experiences C. Limited course offerings D. Poverty
What fraction of the Galaxy's mass is in a form that does not emit electromagnetic radiation?
A. about 90% B. about 10% C. about 50% D. Zero percent; all of the Galaxy emits some form of light.
As we look at larger and larger scales in the universe, we find:
A) smaller and smaller masses. B) almost exclusively visible matter. C) a larger and larger percentage of the matter is visible. D) a larger and larger percentage of the matter is dark. E) an equal amount of visible and dark matter.
If a galaxy is moving away from us the wavelength of the light it emits will be
A. increased. B. blueshifted. C. unaffected. D. distorted. E. decreased.