Globular clusters, big lumps of old stars packed tightly together by gravity, are fairly common, but that doesn't mean we know a lot about them. There are over 150 known ones in the Milky Way alone and more are yet to be discovered.
In many cases, all the stars in the cluster have formed at around the same time, but there are many examples where this is not the case and, what's more, different globular clusters have different star compositions.
For a long time, it was believed that stars in such clusters are the same age, but more and more evidence points to the contrary.
For example, a recent look through the Hubble Space Telescope at the globular cluster known as NGC 6362. Most of the stars in it are old, 10 billion years old, much older than our sun. In fact, they're near the end of their lives.
But some stars among them are much bluer, so much younger, than the rest. This puzzles astronomers as it questions whether all the stars in the cluster formed at the same time.
A more recent theory though suggests that these blue stars, while young looking, are just as old as the rest.
However, they've found the secret to staying young and it's a secret shared by a few supernatural beings back on Earth, they suck the life force from other stars.
More scientifically, these stars merged at one point with one another and the influx of fuel spurred the fusion process once again.
This means there's more light coming out of the star, bluer light at that, giving off the impression that it's a young star in its prime. Another idea is that they accreted material from other sources. The result is the same.
The same cluster was shot using the European Southern Observatory's MPG/ESO 2.2-meter telescope in Chile. These new photos are the best views of the cluster located in the constellation Ara, or The Altar.