One of the great foils of science is the ability of our world and our universe beyond to hide some of the things we are most interested in seeing. Take globular clusters as an example. These pockets of many thousands of stars are generally formed in a single burst of star formation, making the stars in each cluster all of the same age and composition, like cookies all made from the same batch of dough. Different globular clusters will each be of different ages and slightly different chemistries, and by looking at myriad globular clusters, we can get snapshots of how different mass stars and how chemistry changes that evolution.
And they are pretty.
And they are also often filled with the kinds of variable stars that allow us to measure their distances accurately. This means that over the decades, researchers have tried to use globular clusters to help us map our place in space.
It was initially assumed that since globular clusters occupy roughly a sphere around our galaxy, we could measure our position relative to the globular clusters to figure out where we are compared to the center of the galaxy. Unfortunately, just like everything else, globular clusters can get lost in the shine of other stars and blocked by the dust and gas that blocks just about everything.
Today, playing hide and seek with globular clusters is a scientific sport enjoyed by many, including researchers using the Hubble Space Telescope. In a new image release, we can see the majority of red stars of the Liller 1 globular cluster shining faintly behind a crowd of bright blue stars. The blue stars are part of our galaxy’s disk.
And when found, Liller 1 had some amazing secrets to share. While the majority of globular clusters formed stars all at once, we very occasionally will find systems that appear to have had multiple epochs of star formation. Liller 1 is one of those extremely rare systems, and it appears to have formed stars both twelve billion years ago and then again one to two billion years ago. How? Well, that should be the theme of upcoming research, but for now, we have a picture, and that needs to be enough.
While pictures are awesome, let’s face it — we all like to sometimes just escape into a story. What story should or shouldn’t you escape into? This is why we do reviews.
NASA Goddard image release