Cepheid variable stars are useful to astronomers as indicators of:
A) stars with very high-speed motion.
B) white dwarf behavior.
C) the existence of black holes.
D) distance, particularly to nearby galaxies.

Question

Quizplus · Accepted Answer

Cepheid variable stars are useful as distance indicators, particularly to nearby galaxies. The period of variation in brightness can be used to determine the intrinsic brightness, which in turn helps astronomers calculate the distance to the star. This method is known as the cosmic distance ladder and is essential in measuring distances to objects beyond our own Milky Way galaxy.

Cepheid Variable Stars Are Useful to Astronomers as Indicators Of