Credit: NASA/JPL-Caltech/H. Dole (IAS)

When one galaxy wont do the trick, perhaps 20,000 will do. In the blue image on the left, 24 micron images of over 20,000 faint, distant galaxies have been added together. None of these galaxies were detectable, alone, at longer wavelengths. The following green and red images show the resulting combined images at 70 microns and 160 microns, respectively, which result in a clear detection of the galaxies in the until-recently unresolved infrared background.