The quantum cosmology debate

I review the tunneling, Hartle-Hawking and Linde proposals for the wave function of the universe and comment on the recent work on quantum creation of open universes.Comment: Contribution to the debate on quantum cosmology at the COSMO-98 meeting. 9 pages, 6 figure

The vacuum energy crisis

The smallness of the vacuum energy density and its near coincidence with the average matter density of the universe are naturally explained by anthropic selection. An alternative explanation, based on the cyclic model of Steinhardt and Turok, does not address the coincidence problem and is therefore less convincing. This article appeared in ``Science'' (4 May 2006) as a ``perspective'' for Steinhardt and Turok's paper in the same issue (astro-ph/0605173).Comment: 4 pages, no figures; invited "perspective" article in "Science" (4 May 2006