Quasars as probes of the distant and early universe

Quasars are starlike objects with a large red shift. The hypothesis used here is that quasars are the extremely bright nuclei of galaxies too distant to be detected. A new optical method for discovering quasars of large red shift was used. A search for galaxies with strong emission lines was conducted with a 60-cm Schmidt telescope with a prism over the entrance aperture. Then the spectral features were determined in detail in high dispersion spectra yielded by larger telescopes with a Vidicon spectrometer. The Lyman-alpha line is the strongest feature in the quasar spectra. It is generally accepted that red shifts are a good measure of relative distance. The distribution of quasar red shifts supplies many clues to the structure and character of the early universe. The largest quasar red shift known is 3.53. In the 1960's, Schmidt discovered that quasars are more numerous in space at a distance than in our vicinity. It was proposed that quasar red shifts might have a limit. The limit of 3.5 implies abrupt changes in the properties of the universe. One of the simplest solutions is that quasars formed suddenly about 15 billion yrs ago, which would have been a remarkable occurrence in the evolution of the universe. A look at the quasar's three dimensional distribution yields clues to the nature of quasars themselves