How is the age of the galaxy determined
A)measuring the metallicity of Population II stars
B)finding the turnoff point in the H-R diagram of globular clusters
C)from the motion of stars in the galactic halo
D)counting the number of open clusters in the spiral arms

Question

Quizplus · Accepted Answer

The age of the galaxy can be determined by finding the turnoff point in the H-R diagram of globular clusters. This is because all the stars in a globular cluster formed at around the same time, so the turnoff point, where the brightest stars begin to leave the main sequence, gives an estimate of the cluster's age. Since globular clusters are some of the oldest structures in the galaxy, this provides an estimate for the age of the galaxy itself.

How Is the Age of the Galaxy Determined