Hubble carried out the determination of the distance to the Andromeda "nebula" (which finally resolved the Shapley-Curtis debate on the nature of "spiral nebulae") by observing
A) pulsars.
B) Cepheid variable stars.
C) the Doppler shift of stars in the "nebula."
D) the main sequence of stars in the "nebula."

Question

Quizplus · Accepted Answer

Hubble used Cepheid variable stars to determine the distance to the Andromeda Nebula, proving that it was far outside our own galaxy and thus resolving the debate on whether spiral nebulae were part of the Milky Way or distant galaxies.

Hubble Carried Out the Determination of the Distance to the Andromeda