The most accurate way of finding the distance to some very far away stars might be by observing
A) their orbiting planets
B) their motion relative to nearby stars
C) the variation in their position in the night sky on successive nights
D) the rate of variation in their luminosity

Question

Quizplus · Accepted Answer

The most accurate way of finding the distance to some very far away stars is by using the rate of variation in their luminosity. This is because some stars have a well-defined relationship between their luminosity and their period of brightness variation, known as Cepheid variables. By measuring the period of brightness variation, astronomers can determine the luminosity of the star and use this to calculate its distance from Earth using the inverse square law of light.

The Most Accurate Way of Finding the Distance to Some