Globular clusters (GCs) are groups of stars that are tightly packed together by gravity to form a spherical shape in a galaxy. Astronomers view clusters as natural laboratories for studying the evolution of stars and galaxies. In particular, it may help astronomers better understand the history of the formation and evolution of the first types of galaxies. This is because the origins of globular clusters appear to be closely related to the time when many stars were formed.

Recently an international team of astronomers used the Gemini Observatory. and the Hubble Space Telescope of NASA, the United States, and the European Space Agency. Explore the globular cluster NGC 6558, also known as GCL 89 or ESO 456-SC62, a galactic bulge located approximately 24,100 light-years away in the constellation Sagittarius. It is believed to provide important insights into the properties of this type of cluster.

Previous observations have found that NGC 6558 is metallic and may be one of the oldest objects in the Milky Way galaxy. Astronomers estimate that NGC 6558 is about 13 billion years old.