A: To determine the age of a globular cluster, astronomers rely on the assumption that all the stars in the cluster formed at the same time and are the same distance from us. But the stars don’t all ...

Blue straggler stars are the weird grandparents of the galaxy: They should be old, but they act young. Finding and studying these strange stars helps us understand the complicated life cycles of ...

Previously, planets have been detected only in the Milky Way galaxy. Researchers show that quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the ...