  This presentation reports on first evidence for a
low-mass-density/positive-cosmological-constant universe that will expand
forever, based on observations of a set of 40 high-redshift supernovae. The
experimental strategy, data sets, and analysis techniques are described. More
extensive analyses of these results with some additional methods and data are
presented in the more recent LBNL report #41801 (Perlmutter et al., 1998;
accepted for publication in Ap.J.), astro-ph/9812133 .
  This Lawrence Berkeley National Laboratory reprint is a reduction of a poster
presentation from the Cosmology Display Session #85 on 9 January 1998 at the
American Astronomical Society meeting in Washington D.C. It is also available
on the World Wide Web at http://supernova.LBL.gov/ This work has also been
referenced in the literature by the pre-meeting abstract citation: Perlmutter
et al., B.A.A.S., volume 29, page 1351 (1997).
