ASTR 1P01 Lecture : Galaxies

The globular cluster m13 belongs to the ............of the milky way galaxy.

If stars existed but galaxies did not:

(a) we would probably still exist anyway.
(b) we would not exist because life on Earth depends on the light of galaxies.
(c) we would not exist because we are made of material that was recycled in galaxies.

Which of the following statements does not use the term light-year in an appropriate way?
A) A light-year is about 10 trillion kilometers.
B) It's about 4 light-years from here to Alpha Centauri.
C) It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year.
D) The Milky Way Galaxy is about 100,000 light-years in diameter.
E) It will take me light-years to complete this homework assignment.