Hubble’s infrared vision pierced the dusty heart of our Milky Way galaxy, 27 000 light-years away in the constellation of Sagittarius, and reveals more than half a million stars at its core. Those stars are part of the Milky Way’s nuclear star cluster, the most massive and densest stellar cluster in our galaxy. The blue stars in the image are foreground stars, which are closer to Earth than the nuclear star cluster, whilst the red stars are either behind much more intervening dust, or are embedded in dust themselves.

At the very hub of our galaxy, this dense nuclear star cluster surrounds the Milky Way’s central supermassive black hole, known as Sagittarius A*, which is about four million times the mass of the Sun.