NASA/JPL-Caltech/ESA/Spitzer/P. Oesch/S. De Barros/I.Labbe
This deep-field view of the sky (centre) taken by NASA's Hubble and Spitzer space telescopes is dominated by galaxies -- including some very faint, very distant ones -- circled in red. The bottom right inset shows the light collected from one of those galaxies during a long-duration observation.