Apod 4.3

This weeks picture is M 53, a globular cluster. This picture highlights the globular cluster's dense star coverage across what is relatively a small section of the galaxy. Also, although the cluster is primarily made up of stars that are larger, redder, and older than our sun, we can still see some stars holding on to their blue giant like appearance. Astronomers have labeled these stars "Blue stragglers" and they believe that at one point these stars were in a binary system, but the star consumed the other star in order to grow larger and shine brighter.  This fact is very important because we can use an average globular cluster as evidence as to how old the universe is, but with these blue stars, the data would point to another conclusion if not explained properly.

http://apod.nasa.gov/apod/astropix.html