Variable stars such as Cepheid variables are used in what important measurement in astronomy?
A) the measurement of the distances to stars
B) the measurement of the rotation speeds of galaxies
C) the measurement of the surface temperatures of stars
D) the keeping of accurate time

Question

Quizplus · Accepted Answer

Variable stars such as Cepheid variables have a known relationship between their luminosity and their period of brightness variation. This allows astronomers to use them as "standard candles" to measure the distances to far-off galaxies.

Variable Stars Such as Cepheid Variables Are Used in What