Along with these stars are large clouds of gas and dust that, when dense enough, are the nurseries where new stars are born.
When all the gas is either depleted or lost into space, the arms gradually fade away and the spiral shape begins to weaken.
At the end of this process, what remains is a lenticular galaxy, a bright disc full of old, red stars surrounded by what little gas and dust the galaxy has managed to cling on to. This image shows the shape of NGC 524 in detail, formed by the remaining gas surrounding the galaxy’s central bulge.
Observations of this galaxy have revealed that it maintains some spiral-like motion, explaining its intricate structure.
Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt