The location of the Galactic Center was first found by Harlow ...

[dakota nelson]

The location of the Galactic Center was first found by Harlow Shapley with
 
  A) radio emissions from Sagittarius A.
  B) RR Lyrae variables in the globular clusters.
  C) Cepheids of population I in the spiral arms.
  D) infrared observations of the heat from its accretion disk around the black hole.
  E) planetary nebulae in the open clusters.

Question 2

Which of these variable stars would be classified as a Cepheid?
 
  A) a G giant with a period of 14 hours
  B) a B supergiant with a period of 0.14 days
  C) a K giant with a period of 14 days
  D) an F giant with a period of 14 years
  E) an M supergiant with a period of 140 days

[jrpg123456]

Answer to Question 1

B

Answer to Question 2

C