This densely populated group of stars is the globular cluster known as NGC 1841, which is found within the Large Magellanic Cloud (LMC), a satellite galaxy to the Milky Way galaxy that lies about 162 000 light-years away. Satellite galaxies are galaxies that are bound by gravity in orbits around a more massive host galaxy. We typically think of our galaxy’s nearest galactic companion as being the Andromeda Galaxy, but it would be more accurate to say that Andromeda is the nearest galaxy that is not in orbit around the Milky Way galaxy. In fact, our galaxy is orbited by tens of known satellite galaxies that are far closer than Andromeda, the largest and brightest of which is the LMC, which is easily visible to the naked eye from the southern hemisphere (although this is decreasingly the case thanks to light pollution).
More information and download options: esahubble.org/videos/potw2409a/
Credit:
ESA/Hubble & NASA, A. Sarajedini, F. Niederhofer, N. Bartmann
Music: Stellardrone - Ascent