The age of the Milky Way galaxy has been estimated to be at least 13 billion years based on
A)observations of globular clusters.
B)observations of open clusters.
C)21-cm radiation from H I regions.
D)the rotation curve of the galaxy.
E)the energy produced by Sagittarius A*.

Question

Quizplus · Accepted Answer

Globular clusters are among the oldest objects in the Milky Way galaxy, and their ages can be estimated using various techniques such as isochrone fitting and white dwarf cooling. By analyzing the ages of the oldest globular clusters in the Milky Way, astronomers have estimated that the galaxy itself must be at least 13 billion years old.

The Age of the Milky Way Galaxy Has Been Estimated