Hubble Space Telescope image of spiral galaxy NGC 4603, more than 100 million light years away in the constellation of Centaurus (the Centaur). Credit: ESA / Hubble & NASA, J. Maund
This image shows a close-up portrait of the magnificent spiral galaxy NGC 4603, located more than 100 million light-years away in the constellation of Centaurus (the Centaur). Bright bands of blue young stars form the arms of this galaxy, twisting lazily outward from its luminous core. The intricate reddish-brown filaments that run through the spiral arms are known as strips of dust and are dense dust clouds that obscure the galaxy’s diffuse starlight.
This galaxy is a known topic for Hubble. In the last years of the twentieth century, NGC 4063 was watched closely and closely for signs of a peculiar class of stars known as Cepheid variables. These stars have a brightness that is closely related to the period in which they darken and lighten, allowing astronomers to accurately measure how far they are from Earth. Distance measurements with Cepheid variables are the key to measuring the furthest distances in the Universe, and were one of the factors used by Georges Lemaître and Edwin Hubble to show that the Universe is expanding.