Number 78 (Story #3), May 4, 1992 by Phillip F. Schewe and Ben Stein THE EARLIEST INFORMATION FROM THE BIG BANG may ultimately come not from the cosmic microwave radiation (carefully mapped by COBE) but from gravitational perturbations in the early universe. Although not yet detected directly, gravitational waves are an important ingredient in Einstein's theory of general relativity and several international teams are working to observe them with instruments such as the proposed LIGO interferometer. Unlike electromagnetic waves, gravitational waves, according to Einstein's theory, travel through space without being scattered or absorbed by matter. If sufficiently sensitive detectors are ever built, scientists may be able to detect gravity waves from the early moments after the big bang. Whereas electromagnetic waves (upon which most of our knowledge of the universe is based) did not start travelling freely through the universe until 300,000 years after the big bang, gravitational waves are believed to have started travelling through space as early as 10**-42 seconds after the beginning of the universe. (Scientific American, March 1992.)