Concept Test

• Suppose the nearest Cepheids were farther than we had previously thought. What effect would that have on the luminosity we calculate for galaxies.

  • If they are farther, they must be more luminous than we thought
  • If Cepheids are more luminous that we thought, then the ones we see in other galaxies must be farther away than we thought.
  • If other galaxies are farther away, they must be more luminous than we thought.

Notes: