NGC 1365 is enormous. It is one of the largest galaxies known to astronomers—over 200,000 light-years across. This, plus the sharply defined bar of old stars across its structure is why it is also known as the Great Barred Spiral Galaxy. Astronomers believe that the Milky Way, which is only half as big, may look very similar to this galaxy. The bright centre of the galaxy is thought to be caused by huge amounts of superhot gas ejected from the ring of material circling a central black hole. Young luminous hot stars, born in the interstellar clouds, give the arms their blue color. The bar and spiral pattern rotates, with one full turn taking about 350 million years. NGC 1365 is about 61 million light-years away in the constellation Fornax (the Furnace).
Image Credit: ESO