Sunny Priyan
NGC 6558 is closer to the center of the Milky Way than Earth is, and lies about 23,000 light years away in the constellation Sagittarius.
Globular clusters like NGC 6558 are tightly bound collections of tens of thousands to millions of stars, and they can be found in a wide range of galaxies.
As this Hubble Space Telescope observation shows, the stars in globular clusters can be densely packed; this image is thronged with stars in a rich variety of hues.
Some of the brightest inhabitants of this globular cluster are surrounded by prominent diffraction spikes, which are imaging artefacts caused by starlight interacting with the inner workings of Hubble.
Globular clusters offer astronomers natural laboratories, where stars formed at the same time and with similar composition, revealing how different stars evolve under shared conditions.
This image is part of a study exploring globular clusters in the inner Milky Way to better understand their formation and evolution.