While astronomers have delved into the life-cycle of individual stars, understanding the galaxy evolution has proven elusive. One of the major issue is of the immense size in question. For example, the Milky Way is estimated to contain over 400 billion stars, all of which are at difference stages at different times. It’s a massive undertaking.
But recent research from the Harvard-Smithsonian Center for Astrophysics has revealed new data to help us understand what is happening to galaxies in the long run.
The paper, released in the Astrophysical Journal, focuses on the study of globular clusters. These are typically spherical groups of stars, sometimes in the millions, which orbit a central galactic core. Often they are found on the fringes of their host galaxy.
Globular clusters are significant because they have an uncommonly high number of ancient stars, some of the oldest known to astronomy. The Milky Way has some two hundred clusters surrounding it.
What’s more, it is believed that these clusters are the remnants of significantly older galaxies that have degraded, hence their old stars.
The study was focused on the Virgo Cluster, which contains between one and two thousand galaxies and is roughly fifty-four million light-years away from Earth. Ten of the brightest galaxies alone provide 7054 known globular clusters.
Conducted by three astronomers, Raffaele D’Abrusco, Pepi Fabbiano, and Andreas Zezas, the research shows how the shape of globular clusters can inform their age – and in turn both the age and size of the galaxies they once were.
It works like this – when galaxies collide, matter in the form of star clusters, globular formations, gas and dust are transferred between the two. As a result, larger galaxies, i.e. those with a greater overall mass, have a tendency to collect the greater amount of matter after a collision.
Taking in all of this data and putting it into a computer simulation produces the results that the astronomers had predicted: That globular clusters, having been swapped between galaxies, can be good predictors in the age and evolution of said galaxies.
Imagine them as fossil records being passed between two galaxies. The number and size of globular clusters within a particular galaxy can provide a great amount of information.
