Scientists at the Lawrence Livermore National Laboratory are claiming that they may have found echoes left over from ancient supernovae. From the article: "Just as a sound echo can occur when sound waves bounce off a distant surface and reflect back toward the listener, a light echo can be seen when light waves traveling through space are reflected back toward the viewer. The light echoes were discovered by comparing images of the Large Magellanic Cloud (LMC) taken years apart. By precisely subtracting the common elements in each image and analyzing what variable objects remain, the team looked for evidence of dark matter that might distort the light of stars in a transitory way, as part of a second-generation sky survey called SuperMACHO. SuperMACHO builds on the discoveries of the MACHO project, which started at Lawrence Livermore National Laboratory in 1989."