Spiral galaxy M74. Spitzer Space Telescope (SST) infrared image of the spiral galaxy M74. Blue areas represent hot stars and gas. The red areas are cool areas of dust, marking the spiral arms of the galaxy. Infrared observations allow astronomers to see past dust clouds and see stars that are not visible to optical telescopes. M74, which is about 80,000 light years across, is some 30 million light years from Earth, in the constellation of Pisces.