For finding the distances to globular clusters, Harlow Shapley used
A) planetary nebulae.
B) RR Lyrae variables.
C) eclipsing binaries.
D) Type I supernovae.
E) Population I classical Cepheids.

Question

Quizplus · Accepted Answer

Harlow Shapley used RR Lyrae variables as standard candles to estimate the distances to globular clusters. RR Lyrae stars have a well-defined relationship between their luminosity and pulsation period, making them useful for measuring astronomical distances.

For Finding the Distances to Globular Clusters, Harlow Shapley Used